Papers in press

Changes and Evolution of Corn Co-Products for Beef Cattle

Berger, L., Singh, V. — Fri, 20 Nov 2009 12:39:09 PST

The number and nutrient composition of corn based co-products will expand as ethanol producers seek to optimize the efficiency of ethanol production and the value of the co-products they produce. For example, modified wet distillers grains plus solubles are produced by adding the condensed solubles to partially dried distillers grains so that the resulting product contains approximately 50% dry matter. Other innovative technologies have been developed to fractionate corn and(or) distillers dried grains with solubles (DDGS) for recovering additional co-products and improving nutritional composition of DDGS. Two (i.e., wet and dry) corn-fractionation technologies have been developed to remove the germ, pericarp fiber and(or) endosperm fiber before fermentation, resulting in a significant reduction in the amount of DDGS produced and a corresponding increase in its protein content. Other fractionation technologies include removal of oil by centrifugation after fermentation but prior to DDGS production or removal of oil by solvent extraction from DDGS. Technology to recover pericarp fiber by sieving and aspiration after DDGS production has also been developed. Germ, pericarp fiber, endosperm fiber, or oil can be used as feedstocks for producing other marketable co-products or can be used as ingredients in animal diets. One example of a new corn co-product available to the beef industry is bran cake. This product results from combining corn bran (i.e., pericarp fiber) and distillers solubles produced from a corn dry fractionation process. When bran cake replaced a mixture of high-moisture and dry rolled corn at up to 45% of a finishing diet, gains and feed efficiency were improved. In high-forage diets, the corn bran had approximately 85% the energy value of distillers grains. How rapidly these technologies are adopted will be driven by the economics advantages achieved over the traditional dry and wet milling processes.

Effect of polymorphisms in candidate genes on reproduction traits in Finnish pig populations

Sironen, A. I., Uimari, P., Serenius, T., Mote, B., Rothschild, M., Vilkki, J. — Fri, 20 Nov 2009 12:39:08 PST

Reproduction traits play an important role in economically viable piglet production and are closely related to the quality and length of the sow productive life. A high removal rate of young sows is undesirable not only because of associated financial penalties incurred but also due to ethical concerns. Candidate genes and gene pathways have been identified for fertility in model species and recent studies have provided evidence of polymorphisms within these genes being associated with reproduction traits in American Yorkshire/Large White and Landrace populations. In this study we evaluated the impact of single polymorphisms (n = 7) in seven candidate genes; IGFBP1, IGFBP2, IGFBP3, IGFBP5, CPTIA, COX2, and SLC22a5 on reproductive efficiency in Finnish Yorkshire (n = 280) and Landrace (n = 271) populations. In the Finnish Yorkshire population only four of the analyzed markers were polymorphic. Significant effects on farrowing time were detected from the Yorkshire data with polymorphisms within the CPT1A (a = 2.97 days for age at first farrowing), IGFBP3 (a = 0.54 days for farrowing interval > 1 parities), and IGFBP5 (a = 3.22, 1.27, and 0.85 days for age at first farrowing, farrowing interval in first, and later parities, respectively). For the Landrace population, six markers were polymorphic and significant effects were detected for traits affecting the litter size. The polymorphism within COX2 gene had an additive effect of 0.3 piglets for litter size in > 1 parities, and the IGFBP1 gene had an additive effect of 0.21, 0.26, and 0.11 piglets for litter size in first parity, > 1 parities, and still born in > 1 parities, respectively. The additive effect of the SNP within IGFBP2 was 0.16, 0.09, and 0.09 piglets for litter size in > 1 parities, still born in first and later parities, respectively, and finally IGFBP5 had an additive effect of 0.18, 0.07, and 0.07 piglets for litter size in first parity, still born in > 1 parities, and mortality between farrowing and weaning in first parity, respectively. These results support the suitability of candidate gene approach to identification of markers for improving reproductive performance of sows and provide potential markers for marker assisted selection.

Cationic and neutral amino acid transporter transcript abundances are differentially expressed in the equine intestinal tract

Fri, 20 Nov 2009 12:39:07 PST

To test the hypothesis that AA transporter transcripts are present in the large intestine and similarly expressed along the intestinal tract, messenger RNA (mRNA) abundance of candidate AA transporter genes, SLC7A9, SLC7A1, SLC7A8, and SLC43A1, encoding for AA transporters b^0,+AT, CAT-1, LAT-2, and LAT-3, respectively, was determined in small and large intestinal segments of the horse. Mucosa was collected from the equine small (jejunum and ileum) and large intestine (cecum, left ventral colon, and left dorsal colon), flash-frozen in liquid nitrogen, and stored at -80°C. Messenger RNA was isolated from tissue samples, followed by manufacture of complementary DNA. Relative quantitative reverse transcription polymerase chain reaction was conducted using the 2^-^C^_T method, with glyceraldehyde-3-phosphate dehydrogenase serving as the housekeeping gene. Compared to the jejunum, cationic and neutral AA transporter SLC7A9 mRNA abundance was similar in the ileum, cecum, and large intestinal segments. Compared to the jejunum, cationic AA transporter SLC7A1 mRNA abundance was similar in the ileum, and decreased in the cecum, left ventral colon, and left dorsal colon (P < 0.001). Neutral AA transporter SLC7A8 mRNA abundance decreased from the cranial to caudal end of the intestinal tract (P < 0.001). Neutral AA transporter SLC43A1 mRNA abundance was similar in the ileum and left dorsal colon and increased in the cecum (P < 0.01) and left ventral colon (P < 0.1) compared to the jejunum. Cationic and neutral AA transporter SLC7A9 mRNA abundance is similarly expressed in the large compared to small intestine, while cationic AA transporter SLC7A1 is of low abundance in the large intestine; neutral AA transporters SLC7A8 and SLC43A1 are differentially expressed with decreased abundance of SLC7A8 and increased abundance of SLC43A1 in the large intestine. Results indicate that the large intestine may contribute to both cationic and neutral AA uptake and absorption predominantly via transporters LAT-3 and b^0,+AT.

Effects of varying bulk densities of steam-flaked corn and dietary roughage concentration on in vitro fermentation, performance, carcass quality, and acid-base balance measurements in finishing steers

Fri, 20 Nov 2009 12:39:07 PST

Effects of varying bulk densities of steam-flaked corn (SFC) and level of inclusion of roughage in feedlot diets were evaluated in 3 experiments. In Exp. 1, 128 beef steers were used in a 2 x 2 factorial arrangement to evaluate effects of bulk density of SFC (335 or 386 g/L) and roughage concentration (6 or 10% ground alfalfa hay; DM basis) on performance and carcass characteristics. No interactions were observed between bulk density and roughage concentration for performance data. From d 0 to end, cattle fed the 335 g/L SFC had greater overall G:F than those fed 386 g/L SFC, with tendencies for improved G:F with the lower flake weight evident at all 35-d intervals throughout the feeding period. Dry matter intake was less by cattle fed 6 vs. 10% roughage from d 0 to 35 and d 0 to 70, but not for the overall feeding period. Feeding 6 vs. 10% ground alfalfa as the roughage source tended to improve overall G:F. Treatment effects on carcass measurements were generally not significant. In Exp. 2 effects of bulk density of SFC (283, 335, or 386 g/L) and 6 or 10% ground alfalfa hay on IVDMD and in vitro pH were evaluated at 6, 12, 18, and 24 h of incubation. With a reduced-strength buffer in vitro fermentation system, pH increased with increasing bulk density at 6 and 12 h, and IVDMD decreased as bulk density increased. In contrast, in a normal-strength buffer system, there were no treatment differences for IVDMD. In Exp. 3, two diets that varied in bulk density of SFC and roughage concentration (335g/L SFC with 6% alfalfa hay vs. 386 g/L SFC with 10% alfalfa hay) were compared for effects on pattern of feed intake and acid-base balance in Holstein steers (12/treatment). No differences between treatments were noted for blood gases or urine pH; however, day effects were detected for blood pH, partial pressure of CO₂, and urine pH, which generally decreased with increasing time on feed. The 2 treatments had little effect on pattern of feed intake within sampling days, with the exception that the 386 g/L SFC-10% alfalfa hay diet increased percentage of total DMI consumed at 1 and 6 h after feeding on d 14. Within the ranges of bulk density and roughage level studied, 335 g/L SFC with 6% alfalfa hay yielded optimal animal performance with limited effects on in vitro fermentation and acid-base balance.

Fiber-related digestive processes in three different breeds of pigs

von Heimendahl, E., Breves, G., Abel, Hj. — Fri, 20 Nov 2009 12:39:06 PST

The hypothesis examined in this experiment was that, because of intensive selection for greater daily gains and efficient utilization of concentrated low-fiber diets, modern pig breeds differ from old local breeds in their physiological ability to respond to soluble dietary fiber. Thus, the old local breeds, Schwaebisch Haellisches Schwein (SH) and Bunte Bentheimer (BB), and a modern crossbred pig (CB) were used in metabolism trials to study fiber-related digestion, including microbial hindgut fermentation, by applying a colon simulation technique (Cositec) and measuring intestinal glucose transport in Ussing chambers. A basal diet or basal plus 20% dried sugar beet pulp (SBP) as a soluble fiber source was fed to 6 pigs/breed in a 2 x 3 factorial arrangement of treatments. Four pigs of each breed per treatment were used for intestinal anatomical measurements at the end of the metabolism trials. The pigs had an initial average BW of 33.9 ± 3.7 kg. The basal diet was formulated to meet 80% of energy and 100% of nutrient requirements for pigs with 700 g ADG. Feeding the SBP diet reduced total intestinal tract but it increased colon length, elevated water-holding capacity of the digesta, and increased fecal bulk (P < 0.01). The digestibility of OM, CP, and ether extract decreased, while that of NDF and ADF increased by SBP (P = 0.001). Pigs receiving SBP excreted less urinary N and retained more N (P = 0.001). The fecal proportions of undigested dietary and water soluble N increased and those of bacterial and endogenous debris N reduced (P < 0.05) in SBP-fed pigs. The SH pigs had lighter empty cecum weight, shorter colons, and lower NDF digestibility than BB and CB pigs (P < 0.05). Fecal N excretion did not differ among breeds, but SH pigs excreted more urinary N (P = 0.001) than the other breeds. In Cositec, OM, NDF and ADF disappearance rates from cecal chyme of SBP-fed pigs increased (P < 0.05) irrespective of pig breed. Cecal chyme of SBP-fed BB pigs produced more VFA with a smaller proportion of propionate and a wider acetate to propionate ratio than chyme of SBP-fed SH and CB pigs. The intestinal epithelial glucose transport was greater for ileal than for jejunal tissues (P < 0.001) but was not influenced by diet and pig breed. In conclusion, the modern and intensely selected pig breed can utilize SBP fiber as efficiently as the old pig breeds under the present experimental conditions.

Candidate genes analysis for reproductive traits in two lines of rabbit divergently selected for uterine capacity

Fri, 20 Nov 2009 12:39:06 PST

The objective of this work was to analyze 3 functional candidate genes for reproduction in two lines of rabbits divergently selected by uterine capacity. Both lines were selected for 10 generations, and then the selection was relaxed until the 17th generation which was compounded by 61 and 63 does of the High (H) and Low (L) lines, respectively. We sequenced the SCGB1A1 gene, which encodes the main protein secreted by the rabbit in the uterus and seems to play an important role in implantation. We found 6 SNPs in the promoter region co-segregating in 2 haplotypes in both lines with similar frequency. We also analyzed the IGF1 mRNA because of its effects on embryo development, but we did not find any polymorphism between individuals of the two lines. The third gene analyzed was the TIMP1, which encodes a protein involved in many biological processes related to reproduction. We determined the sequence of its promoter region and found one SNP (g.1423A>G) segregating with different frequency in both lines (0.60 for allele A in the H line and 0.82 for allele G in the L line). The association study performed in an F₂ population (N=598) generated by the cross of both lines of rabbits revealed that the AA genotype had 0.88 embryos more than the GG genotype at 72 h of gestation. The difference increased to 2.23 embryos at implantation, but no difference was found between genotypes at birth. These results suggest that the TIMP1 could be a candidate gene for embryo implantation and embryo survival.

Relationships between racing times of Standardbreds and v4 and v200

Lindner, A. E. — Fri, 20 Nov 2009 12:39:05 PST

The objective of the study was to examine the validity of v₄ (velocity run under the defined conditions inducing 4 mmol/L blood lactate concentration [LA]) and v₂₀₀ (velocity run under the defined conditions inducing a heart rate of 200 beats/min) to differentiate performance level among Standardbred racehorses. For this purpose, 19 Standardbred trotting racehorses with differing racing time records in 2 training yards were submitted to a standardized exercise test (SET) to determine their v₄ and v₂₀₀ (6 horses of one yard only). The test consisted of 4 or more consecutive intervals depending on when the blood [LA] of a horse increased above 4 mmol/L. Speed and time trotted in each interval as well as time between consecutive intervals was the same for horses of a training yard. The blood [LA] measured after each interval was plotted exponentially against running speed to derive v₄ from the blood lactate-running speed (BLRS) relationship and the mean heart rate during the intervals was plotted linearly against running speed to derive v₂₀₀ from the heart rate-running speed (HRRS) relationship. The correlation coefficient between v₄ and the racing time record was 0.77 and 0.75 for horses in racing yard A and B, respectively. There was no correlation between v₂₀₀ and the racing time record. Therefore, v₄ is a valid indicator of performance level of Standardbred trotting racehorses; however, v₂₀₀ may be not or to a lesser extent.

Effect of dietary crude protein source on hormone and follicle characteristics in beef heifers

Martin, J. L., Larson, D. M., Stroh, H. L., Cupp, A. S., Funston, R. N. — Fri, 20 Nov 2009 12:39:05 PST

Ground, raw soybeans (SB) or dried distillers grain plus solubles (DDGS) were utilized in heifer development diets to determine the effect of dietary fat and protein source on hormone and follicle characteristics and ADG. The experiment was conducted over 2 yr with 100 June-born heifers (199 ± 2 kg initial BW, n = 50 per yr). The experimental periods were 157 and 207 d in yr 1 and 2, respectively. Heifers were provided a dietary supplement (DM basis) of 1.23 kg SB and 0.40 kg corn or 1.65 kg DDGS between weaning and breeding. Estrus was synchronized with 2 injections of prostaglandin (PGF₂) 14 d apart. Dominant follicles were measured and aspirated via transvaginal ultrasonography 60 h after the second PGF₂ injection. Heifers were exposed to bulls beginning 14 d after aspiration for 45 d. Heifer ADG was greater (P = 0.02) for DDGS heifers in yr 1, but was similar (P = 0.47) in yr 2. However, there was no difference (P = 0.35) in final BW in either year. There was no difference (P ≥ 0.67) in follicle size, follicle hormone concentrations, or pregnancy rate (88%) between yr 1 and 2. Serum estrogen at 48 or 60 h after PGF₂ injection were similar (P ≥ 0.91); however, LH at 60 h in yr 2 tended to be greater (P = 0.07) for DDGS heifers. The percentage of heifers experiencing an LH surge 48 and 60 h after PGF₂ injection was not affected (P ≥ 0.40) by treatment. Calf production was not affected (P ≥ 0.20) by developmental diet. In summary, DDGS and SB have similar effects on hormone and follicle characteristics at the inclusion rates used in these studies.

Adaptability of pregnant Merino ewes to Nevada's cold desert climate

Fri, 20 Nov 2009 12:39:05 PST

Grazing ability is difficult to record in animals under free ranging conditions without sophisticated methods. Alternatively, grazing ability may be indirectly inferred from changes in body weight and production characteristics during the grazing period. The present study investigated the effect of grazing on resource-limited rangelands on body weight, wool characteristics and offspring weaning weights in 905 5/8, 7/8, and fullblood Merino ewes of 2 to 7 years of age during a grazing period of approximately 2.5 months (between January and March). A total of 469 ewes gave birth to a single lamb, 248 to a twin and 188 did not give birth. Body weights were measured and wool samples taken before and after the ewes were allowed to graze freely on the rangelands; absolute change in body weight and change in body weight as a percentage of initial body weight were estimated. On average, grazing on resource-poor rangelands resulted in body weight loss, a reduction in fiber diameter and it’s coefficient of variation and increased staple length. Animals with finer wool at the start of the grazing period lost both phenotypically (r = -0.07, P < 0.05) and genetically (r = -0.23, P < 0.05) less body weight during the grazing period and had a higher probability to carry a lamb (or two) to term (P < 0.05). Animals that lost less body weight produced more greasy fleece (r = 0.09, P < 0.01). Body weight change did not significantly influence offspring weaning weights. Change in body weight was moderately heritable at an h² of 0.29; fiber diameter was highly heritable at an h² of 0.51. Animals with the lowest inclusion of Merino genetics lost more body weight (P < 0.01) during the grazing period and had a more uniform fiber diameter (P < 0.05) but shorter staples (P < 0.05) and less fleece (P< 0.0001) than animals with a higher level of Merino genetics. Our results indicate that animals with finer wool appeared to be better adapted to the cold Nevada desert. Thus, selection for finer wool may positively influence adaptability to resource-limited cold climate conditions; alternatively, body weight change may be selected for directly. Since nutritional deficiencies during pregnancy can have adverse consequences for the offspring, indirect selection for grazing ability would foremost result in healthier ewes that can produce lambs and wool without compromising their welfare.

Maternal selenium supplementation and timing of nutrient restriction in pregnant sheep: Impacts on maternal endocrine status and placental characteristics

Fri, 20 Nov 2009 12:39:04 PST

To determine the effects of maternal Se intake and plane of nutrition during mid and/or late gestation on hormone and metabolite levels in the dam and placental characteristics, pregnant ewe lambs (n = 64) were assigned to 1 of 8 treatments arranged in a 2 x 2 x 2 factorial array: Se level [initiated at breeding; adequate (ASe; 3.05 µg/kg BW) or high (HSe; 70.4 µg/kg BW)] and nutritional level [100% (control; C) or 60% (restricted; R) of NRC recommendations] fed at different times of gestation [d 50 to 90 (Mid) or d 91 to 130 (Late)]. The C ewes had a greater (P = 0.01) percentage change in BW from d 50 than R ewes during both mid and late gestation. Whereas blood urea N was not affected by either Se or nutritional level, R ewes had a greater (P = 0.01) level of circulating on d 66, 78, 106, 120, and 130 of gestation compared with the C ewes. Both Se and timing of nutritional level impacted circulating progesterone; however, only nutritional level impacted thyroxine and triiodothyronine concentrations in the dam. Nutrient restriction during late gestation decreased (P ≤ 0.01) fetal BW and fetal fluid weight compared with the controls (3.75 vs. 4.13 ± 0.10 kg and 1.61 vs. 2.11 ± 0.11 kg). Although neither Se nor nutritional level affected (P ≥ 0.1) placental, caruncular, or cotyledonary weights, cotyledonary cellular proliferation was decreased (P < 0.05) in HSe compared with ASe ewes. In addition, either Se or nutritional level affected vascular endothelial growth factor (VEGFA), VEGFA-receptor 1, VEGFA-receptor 2, and nitric oxide synthase mRNA abundance in the cotyledonary tissue. In the caruncular tissue, either Se or nutritional level affected VEGFA-receptor 1, placental growth factor, and nitric oxide synthase mRNA abundance. Selenium supplementation and duration or timing of nutrient restriction appears to influence the endocrine and metabolic status of the ewe, which may influence nutrient transport and placental function.

Effects of flunixin meglumine on pregnancy establishment in beef cattle

Geary, T. W., Ansotegui, R. P., MacNeil, M. D., Roberts, A. J., Waterman, R. C. — Fri, 20 Nov 2009 12:39:04 PST

The objective of this research was to determine effects of a single injection of the prostaglandin synthesis inhibitor flunixin meglumine (FM; 1.1 mg/kg BW, i.m.) approximately 13 d (range 10 to 15 d) after AI on pregnancy establishment. Three experiments were conducted using estrus-synchronized heifers and cows. Technicians and AI sires were equally represented across treatments within locations and experiments. Bulls were introduced on the day of FM treatment. Pregnancy to AI was diagnosed 28 to 50 d after AI using ultrasonography. In Exp. 1, beef heifers (n = 1,221) were divided within 5 locations to receive FM or no further treatment (control). At insemination, heifers were divided into 2 similar pastures or pens and approximately 13 d later, 1 group of heifers within each location was processed through an animal handling facility to administer FM treatment. There was no location by treatment interaction (P = 0.62) on AI pregnancy rates, so data were pooled. Pregnancy rates to AI were reduced (P = 0.02) among heifers receiving FM-treatment procedure (66%) compared to control heifers (72%). In Exp. 2, suckled beef cows (n = 719) were assigned within 2 locations to receive FM or no further treatment (control) approximately 13 d after AI. At insemination, control and FM cows were divided into separate pastures and only FM cows were handled after AI for FM-treatment procedure. There was no location by treatment interaction (P = 0.75) so data were pooled. Pregnancy rates to AI did not differ (P = 0.80) between FM (57%) and control cows (59%). In Exp 3, beef heifers (n = 247) and suckled beef cows (n = 335) from one location received either no injection (control) or injection of FM approximately 13 d after AI when all cows and heifers were processed through a working facility. Pregnancy rates to AI were not different (P = 0.37) between FM (45%) and control (42%) cows or between FM (56%) and control (55%) heifers. We conclude FM administration at 1.1 mg/kg BW approximately 13 d after AI did not improve pregnancy establishment in beef cows and heifers and that the effects of handling heifers at this time may decrease pregnancy establishment.

Determination of carcass and body fat compositions of grazing crossbred bulls using body measurements

Fernandes, H. J., Tedeschi, L. O., Paulino, M. F., Paiva, L. M. — Fri, 20 Nov 2009 12:39:03 PST

The objectives of this study were to analyze body measurements of 40 crossbred bulls, grazing low quality forage with different supplementation strategies, to estimate inter-relationships among those measurements and carcass and body compositions and to develop systems of equations to predict body fat using body and carcass measurements. Eight animals were harvested at the beginning of the experiment and the remaining animals were harvested at 90 or 220 d. The biometric measures (BM) were obtained the day before the harvest and included hooks width, pins width, pelvic girdle length, rump depth, rump height, abdomen width, body length, height at withers, rib depth, girth, and body diagonal length. Other measurements included full, shrunk, and empty BW, internal physical and chemical fats, body volume, body area, carcass weight, 9 to 11^th rib section weight and composition, fat thickness, subcutaneous fat, intermuscular fat, carcass chemical fat, and empty body physical and chemical fats. The relationships between BM and body components were evaluated and equations to predict body area, body volume, subcutaneous fat, and carcass and body physical and chemical fat were developed. Biological interpretations of the parameter estimates of equations were similar to those found in the literature such as a ratio of 1 kg of subcutaneous fat to 1.6 kg of intermuscular fat and a deposit of 72 to 76% of body fat in the carcass. The first system used to predict carcass and empty body physical and chemical fat was devised using in vivo information whereas the second system used BW and the 9 to 11^th rib fat weight. Our results indicated the combination of BW, carcass traits, and BM was precise and accurate in estimating carcass and body fat composition of backgrounding bulls. The second system had better adequacy statistics (r² > 0.92, concordance correlation coefficient (CCC) > 0.957, and root mean square error (RMSE) < 14.4% of the average observed value) compared to the first system. The first system had acceptable adequacy statistics (r² > 0.767, CCC > 0.866, and RMSE varying from 15.8 to 22.3% of the average observed value). For both systems, the simultaneous F-test of the linear regression of observed on model-predicted values indicated intercepts were equal to zero and slopes were equal to one (P > 0.246). We concluded that BM can improve the accuracy and precision of the predictions of body composition of grazing animals.

Effect of Pen mates on Growth, Backfat Depth and Longissimus Muscle Area of Swine

Hsu, W. L., Johnson, R. K., Van Vleck, L. D. — Fri, 20 Nov 2009 12:39:03 PST

Records on final weight (kg), backfat depth (cm) and longissimus muscle area (cm²) of pigs of a University of Nebraska, Large White/Landrace, composite population were analyzed to estimate effects of pen mates. Measurements were at approximately 180 d of age for 3,524 pigs in 351 pens (9 - 11 pigs per pen) farrowed from 1999 - 2005. Area of each pen was 8.13 m². The full model (M1) included fixed effects of contemporary group, sex, line and covariates of age and inbreeding coefficient; and random direct additive genetic (a), genetic pen mate (pg) and permanent environmental (pe), pen, litter, and residual effects (e). A derivative-free algorithm was used to obtain REML estimates of variance components for final weight adjusted to 180 d of age with the full model and seven reduced models and with four reduced models for the carcass traits. For final weight likelihood ratio tests showed that M1 did not fit the data better than Model 2 (pe omitted from Model 1) or Model 3 (pen omitted from Model 1). Model 2 was not significantly better than Model 3 which shows that variance due to pen effects and permanent environmental effects cannot be separated. Large sampling variances of estimates of the pen component of variance for models with pen mate effects also indicate inability to separate pen effects from effects of pen mates. When pen mate genetic effects were not in the model, estimates of components of variance and fit of the data were the same for Model 4 (included both permanent environmental and pen effects) and Model 6 (included pen effects) and Model 7 (included permanent environmental effects) which shows including both pen and permanent environmental effects was no better than including one or the other. Models 4, 6 and 7 were significantly better than Model 8 which did not include pen mate effects and pen effects which implies pen effects are important. The estimate of pen variance with M2 was about (number of pen mates minus one) times the estimate of variance of pen mate permanent environmental with M3. Patterns of estimates of variance components with M2, M5, M6 and M8 for backfat depth and longissimus muscle area were similar to those for final weight. Estimates of direct genetic variance and phenotypic variance were similar for all models. Estimates of heritability for direct genetic effects were about 0.40 for final weight, 0.45 for backfat depth and 0.27 for longissimus muscle area. Estimates of heritability for pen mate genetic effects were 0.001 for the three traits for models including either pen or permanent environmental effects. Under management conditions for this experiment, the conclusion is that the model for genetic evaluation should include litter effects and either pen effects or pen mate permanent environmental effects and possibly genetic pen mate effects, in general agreement with results of studies of different populations at other locations.

A calcitonin receptor (CALCR) single nucleotide polymorphism is associated with growth performance and bone integrity in response to dietary phosphorus deficiency

Fri, 20 Nov 2009 12:39:02 PST

While concerns over the environmental impact of excess P in the excreta from pig production and governmental regulations have driven research towards reducing dietary supplementation of P to swine diets for over a decade, recent dramatic increases in feed costs have further motivated researchers to identify means to further reduce dietary P supplementation. We have demonstrated that genetic background impacts P utilization in young pigs and have identified genetic polymorphisms in several target genes related to mineral utilization. In this study, we examined the impact of a single nucleotide polymorphism (SNP) in the calcitonin receptor gene (CALCR) on P utilization in growing pigs. In Experiment 1, 36 gilts representing the 3 genotypes identified by this CALCR SNP (11, 12, and 22) were fed either a P adequate (PA) or a marginally P deficient (approximately 20% less available P; PD) diet for 14 wk. As expected, P deficiency reduced plasma P concentration, bone strength, and mineral content (P < 0.05). However, the dietary P deficiency was mild enough to not affect the growth performance of these pigs. A genotype x dietary P interaction (P < 0.05) was observed in measures of bone integrity and mineral content, with the greatest reduction in bone strength and mineral content due to dietary P deficiency being associated with the allele 1. In Experiment 2, 168 pigs from a control line and low residual feed intake (RFI) line were genotyped for the CALCR SNP and fed a P adequate diet. As expected, pigs from the low RFI line consumed less feed but also gained less when compared to the control line (P < 0.05). Although ADFI did not differ between genotypes, pigs having the 11 genotype gained less weight (P < 0.05) than pigs having either the 12 or 22 genotypes. Pigs of the 11 and 12 genotypes had bones that tolerated greater load when compared to animals having the 22 genotype (P < 0.05). A similar trend was observed in bone modulus and ash % (P < 0.10). These data are supportive of the association of this CALCR SNP with bone integrity and its response to dietary P restriction. While the allele 1 is associated with greater bone integrity and mineral content during adequate P nutrition, it is also associated with the greatest loss in bone integrity and mineral content in response to dietary P restriction. Understanding the underlying genetic mechanisms that regulate P utilization may lead to novel strategies to produce more "environmentally-friendly" pigs.

Yeast cell-wall products containing {beta}-glucan plus ascorbic acid affect neonatal Bos-taurus calf leukocytes and growth after a transport stressor

Eicher, S. D., Wesley, I. V., Sharma, V. K., Johnson, T. R. — Fri, 20 Nov 2009 12:39:02 PST

The objectives were to ascertain if a yeast cell-wall derivative that is 1.8% β-glucan in combination with ascorbyl-2-polyphosphate can improve innate immunity and mediate transportation stress in neonatal calves, and compare the 1.8% β-glucan yeast cell-wall derivative with a more purified yeast cell-wall derivative (70% β-glucan). Treatments were: (1) an unsupplemented control (CNT); (2) 113 g of a 1.8% (approximately 2%) β-glucan derivative of yeast cell-walls plus a 250 mg of L-ascorbic acid phosphate (BG2); or (3) 150 mg of a purified β-glucan fraction from yeast cell-walls, approximately 70% β-glucan, plus L-ascorbic acid phosphate (BG70). Calves (n = 39) were transported for 4 h, placed in outdoor hutches, and randomly assigned to treatments. Treatments (mixed with a milk replacer) were individually fed twice daily for 28 d. Calves were offered calf starter, free-choice, throughout the study. Weekly starter intake and BW were measured, and fecal samples were collected for Salmonella typhimurium and Echerichia coli O157:H7 PCR analysis. Blood was collected immediately before transport (d 0) and on d 3, 7, 10, 14, 21, and 28 after transport. Starter intake and DMI were less (P < 0.05) at d 28 for BG2 and BG70 compared with CNT. Hematocrit percentages increased (P = 0.002) throughout the experiment. White blood cell counts (treatment x time interaction, P = 0.066) were less for the BG70 calves compared with the BG2 (P = 0.01) and CNT (P = 0.04) calves on d 28. Granulocyte counts changed (P = 0.04) throughout the experiment. A trend (P = 0.077) for a treatment x time interaction was detected for peripheral blood mononuclear cell counts (PBMC). Counts of PBMC were greater (P = 0.006) for BG2 compared with CNT calves on d 3. Calves given BG70 supplement had fewer PBMC than BG2 calves on d 21 (P = 0.03) and on d 28 (P = 0.05). Fibrinogen concentrations were affected only by time (P = 0.002). Time effects were detected for phagocytosis (P = 0.005), oxidative burst (P < 0.001), and expression of cluster of differentiation (CD)18 (P = 0.001) and high CD18 (P = 0.006). Phagocytosis was less (P = 0.05) for BG70 than for CNT. Percentage of calves positive for E. coli O157:h7 were greatest (P ≤ 0.05) for BG2 on d 7 compared with other treatments. Both BG2 and BG70 supplements increased feed intake but only BG2 increased E. coli shedding on d 7, and BG2 and BG70 varied in modulation of immune functions indicating differences in yeast extract function.

The effect of diet composition on tryptophan requirement of young piglets

Jansman, A. J. M., van Diepen, J. Th. M., Melchior, D. — Fri, 20 Nov 2009 12:39:01 PST

The aim of the study was to evaluate the requirement for Trp in relation to diet composition in piglets in the period after weaning (BW range of 9 to 24 kg). Two Trp deficient (relative to the Dutch (CVB, 1996) and NRC (NRC, 1998) requirement values for piglets of 10 to 20 kg BW) basal diets were formulated; one based on corn and soybean meal and a second one based on wheat, barley, soybean meal, peas and whey powder (10.0 g/kg apparent ileal digestible (AID) Lys; 1.4 g/kg AID Trp; 1.5 g/kg standardised ileal digestible (SID) Trp). Both basal diets were supplemented with 0.3, 0.6 and 0.9 g L-Trp per kg diet to obtain diets with 1.7, 2.0 and 2.3 g AID Trp per kg (1.8, 2.1 and 2.4 g SID Trp per kg), respectively. Each of the 8 treatments was evaluated in 8 replicates (pens with eight male or female piglets). Average daily feed intake, ADG, and G:F were measured as response criteria. Over the 28-d experimental period, ADG and G:F were greater for the treatments on the wheat/barley diet compared to those on the corn/soybean meal and were increased by the level of Trp in the diet (P < 0.05). Average daily feed intake was only increased by the level of Trp supplementation (P < 0.05). Increasing the Trp level increased ADFI for the corn/soybean meal diet up to 2.3 g AID Trp per kg (2.4 g SID Trp per kg) and up to 2.0 g AID Trp per kg (2.1 g SID Trp per kg) in the wheat/barley diet (P < 0.05). For both diets types supplementation of free L-Trp increased the G:F up to 1.7 g AID Trp per kg (1.8 g SID Trp per kg). Non-linear regression analysis of the response curves for ADFI using an exponential model for estimating a requirement value for Trp (defined as the Trp level resulting in 95% of the maximum response) revealed a requirement estimate of 2.3 g AID Trp per kg for the corn/soybean meal based diet and 2.1 g AID Trp per kg for the wheat/barley based diet, equivalent to 2.4 and 2.2 g SID Trp per kg diet, respectively. For ADG, a requirement estimate of 2.1 g AID Trp per kg for both types of diets was derived, equivalent to 2.2 g SID Trp per kg diet. The Trp requirement for young piglets seems to be greater than indicated by some commonly used recommendations and does not seem largely dependent on diet ingredient composition.

Cinnamaldehyde in feedlot cattle diets: intake, growth performance, carcass characteristics, and blood metabolites

Yang, W. Z., Ametaj, B. N., Benchaar, C., He, M. L., Beauchemin, K. A. — Fri, 20 Nov 2009 12:39:01 PST

Cinnamaldehyde (CIN), a natural chemical compound found in the bark of cinnamon trees, can alter rumen fermentation by inhibiting selected ruminal microbes, and consequently, may improve growth performance and feed efficiency of the animals. The objective of this study was to evaluate the effects of supplementing the diet of feedlot cattle with CIN on intake, growth performance, carcass characteristics, and blood metabolites. Seventy yearling steers (BW = 390 ± 25.2 kg) were assigned to a randomized complete block design with 5 treatments: control (no additive), monensin (MO; 330 mg•steer^-1•d^-1), 400, 800, or 1600 mg of CIN•steer^-1•d^-1. At the start of the experiment, steers were blocked according to BW and assigned to 14 blocks of 5 cattle, with cattle within block assigned to treatments. The diets consisted of 9% barley silage, 86% dry-rolled barley grain, and 5% supplement (DM basis). Dry matter intake responded quadratically to level of CIN supplementation with 13% more feed consumed for steers fed CIN (mean of 3 CIN levels) compared with those fed control during the first 28 days of the experiment, and with a tendency of 4% increase over the entire experiment. The ADG (kg/d) tended to respond quadratically to level of CIN supplementation during the first 28 days, but was not affected over the entire experiment (112 d). Feed efficiency (gain/intake) linearly declined during the first 28 days with level of CIN supplementation and was quadratically affected between d 29 to 56 and d 85 to 112 by CIN dose. Supplementation of MO did not affect DMI or growth performance at any time during the experiment. Serum NEFA concentrations were reduced by 35, 29, 30, and 22%, respectively, on d 56, 84, 112, and overall with CIN supplementation. Concentrations of serum amyloid A were reduced on d 28 by 56, 60 or 56% for medium CIN, high CIN, or MO, respectively, compared with control. Plasma concentrations of lipopolysaccharide binding protein were linearly decreased with increasing CIN supplementation on d 28. Results indicate that supplementing a feedlot finishing diet with a low dose of CIN ameliorated feed intake during the initial month, but had minimal effects on ADG, feed efficiency, and carcass traits over the entire experiment. Including CIN in the diet of feedlot cattle, particularly early in the feeding period, may help promote intake and reduce the effects of stress.

Behavior and peripheral amine concentrations in relation to ractopamine feeding, sex and social rank of finishing pigs

Poletto, R., Meisel, R. L., Richert, B. T., Cheng, H. W., Marchant-Forde, J. N. — Fri, 20 Nov 2009 12:39:00 PST

Aggression can impair productivity and well-being. The association between aggression in finishing pigs and the feed additive ractopamine (RAC), a β-adrenoreceptor agonist, is unknown and warrants further investigation. Our goal was to examine behavioral activity, including aggression, in the home pen and concentrations of peripheral amines in barrows and gilts, taking into account diet (RAC) and social rank. Sixty-four finishing pigs, housed in pens of 4 by sex, were fed either control (CTL) or RAC-added (5 mg/kg for 2 wk plus 10 mg/kg for another 2 wk) diet. The top dominant and bottom subordinate pigs in each pen were determined at mixing, 2 wk pre-trial. Behavior of all pigs was continuously recorded during the pre-trial week (baseline) and for the following 4 wk. These behavioral data were used to evaluate home pen aggression, including the number of agonistic interactions (AINX) and constituent aggressive actions, during a 3-h period (0800-1100) once per week and their change in relation to baseline. Time-budget behaviors and postures were analyzed over 8 x 24-h periods (2 d/wk) using 10-min instantaneous scan sampling that focused only on the dominant and subordinate pigs in each pen. These 2 pigs were also subjected to blood collection once per week during the trial to determine concentrations of dopamine (DA), norepinephrine (NE), epinephrine (EPI), and serotonin (5-HT) using HPLC. Gilts performed more bites and total actions per AINX than barrows, and RAC-fed gilts increased bites and pursuits while others decreased when compared to baseline values (P < 0.05). Gilts fed RAC increased the total number actions per AINX, while the occurrence of AINX decreased for all subgroups (P < 0.01). Overall, RAC-fed pigs were more behaviorally active, spending more time alert, bar-biting and sham-chewing compared to CTL pigs (P < 0.05). The dominant RAC-fed pigs tended to have highest NE concentrations among the tested subgroups (P = 0.08). Dominant barrows had higher EPI concentrations than subordinate barrows (P < 0.05). The RAC-fed gilts tended to have lower 5-HT concentrations than CTL gilts (P = 0.08), while concentrations were similar in barrows (P > 0.10). Greater activity and the increase in oral-related behaviors observed in RAC-fed pigs may be mediated by the increase in arousal caused by RAC. Intensified aggression in gilts, especially when fed RAC, may be linked to lower central 5-HT and greater noradrenergic activity, and further research on brain neurotransmitters in gilts is needed.

The effect of rumen degradable and rumen un-degradable intake protein on feedlot performance and carcass merit in heavy-yearling steers

Wagner, J. J., Engle, T. E., Bryant, T. C. — Fri, 06 Nov 2009 08:41:37 PST

Four hundred and thirty-two crossbred yearling steers (395 kg ± 6.35) were utilized in a randomized block experiment to study the effects of rumen degradable intake protein (DIP) and rumen un-degradable intake protein (UIP) concentration on feedlot performance and carcass merit. Six dietary treatments utilized for this study included: a 10.5% CP diet with 5.1% UIP and 5.4% DIP (DIP5); an 11.5% CP diet with 5.1% UIP and 6.4% DIP (DIP6); a 12.5% CP diet with 5.1% UIP and 7.4% DIP (DIP7); a 13.5% CP diet with 5.1% UIP and 8.4% DIP (DIP8); a 14.5% CP diet with 5.1% UIP and 9.4% DIP (DIP9); and a 14.5% CP diet with 6.1% UIP and 8.4% DIP with the additional UIP provided by corn gluten meal (CGM). There was a linear increase in final BW and ADG and a trend for a linear increase in DMI associated with increasing DIP concentration within the 5.1% UIP treatments. Feed efficiency and net energy recovered from the diet were not influenced by dietary DIP concentration. As diet DIP concentration increased, carcass fat depth and average yield grade (YG) increased linearly and the percentage YG 1 and 2 carcasses decreased linearly. Diet UIP treatment had no effect on final BW, ADG, DMI, G:F, and calculated net energy recovery. For the 14.5% CP diets, marbling score tended to be reduced for steers fed 6.1% UIP as compared with 5.1% UIP. Remaining carcass traits were not impacted by dietary UIP. The results of this study show that the DIP requirement in the finishing diet for heavy yearling steers fed steam-flaked corn is greater than 7.4% of diet DM but likely not more than 8.4% of diet DM when diet UIP is approximately 5.1% of diet DM. Increasing UIP above 5.1% of diet DM did not improve feedlot performance or HCW. Expressed on a CP basis, it appears as if the requirement for CP for heavy yearling steers fed steam-flaked corn based finishing diets is 13.5% of DM with approximately 62% of CP from DIP.

Expression of progesterone receptor related to the polymorphism in the PGR gene in the rabbit reproductive tract

Fri, 06 Nov 2009 08:41:36 PST

The association of the 2464G>A SNP found in the promoter region of the rabbit progesterone receptor gene with progesterone receptor expression was evaluated by Western blot analysis. This SNP was associated with 2 lines divergently selected for uterine capacity, the High line selected to increase uterine capacity and the Low line selected to decrease it. Two progesterone isoforms were obtained using a commercial monoclonal antibody: the PR-B isoform previously described in rabbits, and the PR-A isoform, not previously described in rabbits. The GG genotype, the genotype more frequent in the High line, showed lower PR-B and PR-A expression than the AA genotype in the oviduct (GG/AA_PR-B = 0.81 and GG/AA_PR-A = 0.73) and uterus (around 0.70 in both isoforms). The GA genotype showed similar PR-A expression in both tissues and also similar PR-B expression in the oviduct to the GG genotype. Conversely, the GG genotype showed lower PR-B expression than the GA genotype in the uterus (GG/GA_PR-B =0.79). Similar expression of both PR isoforms was found in the uterus at d 2 and 3 of gestation; meanwhile, an increase of both isoforms was observed in the oviduct. Similar PR-A expression was observed in the ampulla and isthmus; meanwhile, the PR-B expression in the isthmus was double that in the ampulla.

Utilization and Application of Wet Potato Processing Co-Products for Finishing Cattle

Nelson, M. L. — Fri, 06 Nov 2009 08:41:35 PST

Wet co-products fed to beef cattle include processing co-products of the fruit, vegetable, juice, and brewing industries. Considerations for their utilization in beef cattle diets include quantity available, feeding value, quality of animal products produced, economics (e.g., transportation of water), storage and preservation, consumer perception, nuisance concerns, contaminants, and interactions with other diet ingredients. Potato (Solanum tuberosum) co-products from processing for frozen food products may be quantitatively most important because the 11.3 million t of potatoes (fresh weight) processed in the United States and Canada in 2008 resulted in an estimated 4.3 million t (as is basis) of co-product. Chemical composition and feeding value of potato co-products depends on the co-product type. The names of co-products vary among potato processors and some processors combine the different co-products into one product commonly called slurry. The four main potato co-products are: 1) potato peels; 2) screen solids (small potatoes and pieces); 3) fried product (fries, hash browns, batter, crumbles); and 4) material from the water recovery systems (oxidation ditch, belt solids, filter cake). The co-products, except the fried products, ensile rapidly, reaching pH 5 in 7 d or less. Dry matter content varies from 10 to 30% and varies, on a DM basis, in CP (5 to 27%), starch (3 to 56%), NDF (4 to 41%), and ether extract (3 to 37%) content among potato co-products. Type of co-product and frying greatly affect the energy value (0.6 to 1.6 Mcal NEg/kg DM). Composition, quality, and shelf life of beef was not affected by potato co-product feeding in contrast to perceptions of some purveyors and chefs. Potato co-products are quantitatively important energy sources in beef cattle diets, which, in turn, solve a potentially massive disposal problem for the food processing industry.

The potential ability of swine nutrition to influence environmental factors positively

Petersen, S.T. — Fri, 06 Nov 2009 08:41:34 PST

Environmental issues are a growing concern within agriculture. Several of them can be categorized under the following headings: manure storage and handling, air quality, manure nutrient concentration, and soil nutrient levels. Recently introduced, EcoCare feed (Land O’Lakes Purina Feed LLC, Shoreview, MN) is a dedicated and affordable feeding program addressing manure management, ammonia emissions, and nutrient excretion, while optimizing pig performance. Components in EcoCare feed reduce manure solids and viscosity, resulting in improved physical uniformity of the manure that is easier to agitate in manure storage pits and manipulate through manure-handling equipment. Internal research trials have indicated a reduction of 14% in solids and 22% in viscosity over a 45-d collection period; these physical changes may have positive implications on manure pit pump-out and facility sanitation. EcoCare feed also has the potential to reduce ammonia emissions. This is achieved primarily by using crystalline amino acid inclusion, specific Bacillus bacteria, and saponin-derived compounds. Emissions measured in a manure pit simulation trial performed at LongView Animal Nutrition Center (Gray Summit, MO) demonstrated that pigs consuming EcoCare feed excreted manure that had ammonia volatilization reduced by 18% over a 45-d period when compared with control pigs. Over time, EcoCare feed may result in reduced production of ammonia by up to 40% in commercial situations. Nutrient manipulation of feed can help greatly in the reduction of nutrient waste. Reducing N loss can be achieved by incorporating supplemental crystalline amino acids in the diet and by using specific feed additives that can lower the volatilization of N-containing ammonia from manure pits. The excretion of P can be reduced by using phytase in the diet, thereby improving P digestibility and reducing the requirement of dietary inorganic P. These types of manipulation can be achieved without limiting swine growth performance. In fact, EcoCare feed has been shown to improve feed conversion ratio by up to 4% over other standard feeds in field conditions. EcoCare is a registered trademark of Land O’Lakes Purina Feed LLC.

A Review of Population Data Utilization in Beef Cattle Research

Jones, R., Langemeier, M. — Fri, 06 Nov 2009 08:41:33 PST

Controlled experimentation has been the most common source of research data in most biological sciences. However, many research questions lend themselves to the use of population data, or combinations of population data and data resulting from controlled experimentation. Studies of important economic outcomes, such as efficiency, profits, and costs, lend themselves particularly well to this type of analysis. Analytical methods that have been most commonly applied to population data in studies related to livestock production and management include statistical regression, and mathematical programming. In social sciences, such as applied economics, it has become common to utilize more than one method in the same study to provide answers to the various questions at hand. Of course, care must be taken to ensure that the methods of analysis are appropriately applied; however, a wide variety of beef industry research questions are being addressed using population data. Issues related to data sources, aggregation levels, and consistency of collection often surface when using population data. These issues are addressed by careful consideration of the questions being addressed and the costs of data collection. Previous research across a variety of cattle production and marketing issues provides a broad foundation upon which to build future research. There is tremendous opportunity for increased use of population data, and increased collaboration across disciplines to address issues of importance to the cattle industry.

Effect of feed restriction and supplemental dietary fat on gut peptide and hypothalamic neuropeptide mRNA concentrations in growing wethers

Relling, A. E., Pate, J. L., Reynolds, C. K., Loerch, S. C. — Fri, 06 Nov 2009 08:41:32 PST

The objectives of the present study were: 1) to evaluate the effect of supplemental fat and ME intake (MEI) on plasma concentrations of glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), glucose-dependent insulinotropic polypeptide (GIP), ghrelin and oxyntomodulin (OXM); and 2) to determine the association of these peptides with DMI and the hypothalamic concentration of messenger (m) RNA for the neuropeptides:neuropeptide Y (NPY), agouti-related peptide (AgRP), and proopiomelanocortin (POMC). Using a completely randomized block design with a 2 x 2 factorial arrangement of treatments, 32 pens with 2 wethers each were restricted-fed (2.45 Mcal•lamb^-1•d^-1) or offered feed ad libitum (n = 16) diets with or without 6% supplemental fat (n = 16) for a period of 30 d. Dry matter intake was measured daily. On d 8, 15, 22, and 29, BW was measured before feeding and 6 h after feeding blood samples were collected for plasma measurement of insulin, GLP-1, CCK, ghrelin, GIP, OXM, glucose and NEFA concentrations. On d 29, blood was collected 30 min before feeding for the same hormone and metabolite analyses. At the end of the experiment, wethers were slaughtered and the hypothalami were collected to measure concentration of NPY, AgRP, and POMC mRNA. Offering feed ad libitum (resulting in greater MEI) , increased plasma insulin and NEFA concentration (P = 0.02 and 0.02, respectively) and decreased hypothalamic mRNA expression of NPY and AgRP (P = 0.07 and 0.02, respectively) compared with the restricted-fed wethers. There was a trend for the addition of dietary fat to decrease DMI (P = 0.12). Addition of dietary fat decreased insulin and glucose concentration (P < 0.05 and 0.01, respectively) and tended to increase hypothalamic mRNA concentration for NPY and AgRP (P = 0.07 and 0.11, respectively). Plasma GLP-1 and CCK concentration increased in wethers offered feed ad libitum compared with those restricted-fed, but the response was greater when wethers were offered feed ad libitum and had supplemental fat in the diet (fat x intake interaction, P = 0.04). Pre-feeding plasma ghrelin concentration was higher in the restricted-fed wethers compared with those offered feed ad libitum, but the concentration was similar 6 h after feeding (Intake x Time interaction, P < 0.01). Supplemental dietary fat did not affect (P = 0.22) plasma ghrelin concentration. We conclude that insulin, ghrelin, CCK and GLP-1 may regulate DMI in sheep by regulating the hypothalamic gene expression of NPY, AgRP, and POMC.

Assessment of goat fat depots using ultrasound technology and multiple multivariate prediction models

Peres, A. M., Dias, L. G., Joy, M., Teixeira, A. — Fri, 06 Nov 2009 08:41:31 PST

Assessment of fat depots for several goat body parts is an expensive and time-consuming task, requiring a trained technician. Therefore, the establishment of models to predict fat depots based on data requiring simpler and easier procedures, such as ultrasound measurements, that could be carried out in vivo, would be a major advantage. An interesting alternative to the use of multiple linear regression models is the use of partial least squares or artificial neural network models, because they allow the establishment of one model to simultaneously predict different fat depots of interest. In this work, the applicability of these models to simultaneously predict 7 goat fat depots (subcutaneous fat, intermuscular fat, total carcass fat, omental fat, kidney and pelvic fat, mesenteric fat, and total body fat) was investigated. Although satisfactory correlation and prediction results were obtained using the multiple partial least squares model (cross-verification and validation R² and standard prediction error values between 0.66 and 0.98 and 247 and 2,168, respectively), the best global correlation and prediction performances were achieved with the multiple radial basis function artificial neural network (verification and validation R² and standard prediction error values between 0.82 and 0.96 and 304 and 1,707, respectively). These 2 multiple models allowed correlating and predicting simultaneously the 7 goat fat depots based on the goat BW and on only 2 ultrasonic measures (lumbar subcutaneous fat between fifth and sixth vertebrae and the fat depth at third sternebra). Moreover, both multiple models showed better results compared with those obtained with multiple linear regression models proposed in previous work.

Differential expression of liver proteins in Chianina and Holstein young bulls

Miarelli, M., Signorelli, F. — Fri, 06 Nov 2009 08:41:31 PST

The purpose of this work was to produce and compare liver proteomic maps of cattle breeds that have been selected for different purposes: dairy (Holstein) and beef (Chianina). Liver was chosen because it displays functions of synthesis, homeostasis, excretion, and defense. Two dimensional electrophoresis (2-DE) analysis was performed on bovine livers collected from 4 individuals of each breed to evaluate differential protein expression. We found 9 spots differing in photodensity by ≥ 2-fold between the 2 breeds. Spots were analysed through combined MALDI-MS and LC-MS/MS. A search against protein sequences in the NCBI databases indicated that the differentially-expressed proteins correspond to liver-specific enzymes, with a major role in the metabolism of fatty acids, carbohydrates, amino acids, and the urea cycle.

Relationships of behavioral and physiological symptoms of pre-slaughter stress to beef LM tenderness

Fri, 06 Nov 2009 08:41:30 PST

Relationships between behavioral and physiological symptoms of pre-slaughter stress and LM Warner-Bratzler shear force (WBSF) were investigated using Bos taurus steers (n = 79) and heifers (n = 77). Measurements of heart rate, respiration rate, rectal temperature, and concentrations of serum cortisol and plasma epinephrine were used as indicators of stress associated with physical handling and chute restraint, while concentrations of cortisol, glucose, lactate, and creatine kinase in blood samples obtained at exsanguination were measured to reflect physiological reactions of animals to transportation stress. Increased plasma epinephrine concentration, indicative of acute handling stress, was associated with elevated heart rate (r = 0.42, P < 0.001) and rectal temperature (r = 0.34, P < 0.001) during restraint, increased plasma lactate (r = 0.22, P = 0.006) and serum creatine kinase (r = 0.28, P < 0.001) concentrations at slaughter, and greater LM WBSF (r = 0.22, P = 0.006). Plasma lactate concentration at slaughter, which reflected an adrenergic stress response to transportation, was associated with lower final LM pH (r = -0.30, P < 0.001) and higher LM WBSF (r = 0.26, P = 0.002). Categorical analyses of chute and post-transportation behavior scores (calm vs. restless vs. nervous) showed that cattle exhibiting adverse behavioral reactions to handling and chute restraint had increased (P < 0.05) values for plasma epinephrine concentration, heart rate, and rectal temperature during chute restraint, elevated (P < 0.05) plasma lactate concentration at slaughter, and increased (P < 0.05) LM WBSF. In addition, cattle showing behavioral symptoms of stress following transportation had higher (P < 0.05) plasma glucose and lactate concentrations at slaughter and produced LM steaks that were 0.34 kg tougher (P < 0.05) when compared with calm cattle. No carcasses were identified as dark cutters, and LM pH did not differ (P > 0.05) among behavior categories. Grouping cattle according to differences in plasma lactate concentration categorized them according to mean differences in LM WBSF. Moreover, steaks from cattle with the highest plasma lactate concentrations at slaughter (91^st to 100^th percentile) had a delayed response to aging that persisted until 14 d postmortem. Stress-induced differences in LM tenderness observed in this study were independent of differences in muscle pH.

Metabolic maturity at birth and neonate lamb survival: Association among maternal factors, litter size, lamb birth weight, and plasma metabolic and endocrine factors on survival and behavior

Miller, D. R., Blache, D., Jackson, R. B., Downie, E. F., Roche, J. R. — Fri, 06 Nov 2009 08:41:30 PST

This paper reports an investigation into metabolic and endocrine maturity in the neonate lamb, and the relationships between litter size, birth weight, and maternal metabolic and endocrine parameters on behavior at birth and survival over the first 72 h of life. Data were from multiparous, fine-wool Merino ewes (n = 150: equal numbers of single-lamb and twin-lamb bearing status) lambed on pasture following late gestational glucocorticoid treatments. Stepwise multiple regression analysis was used to investigate relationships between lamb survival, behavior, endocrinology, and physiology. Improved lamb viability at 72 h after birth was related to lower chill indices at birth, singleton litter status, greater pre-suckling rectal temperature, increasing ewe pre-lambing plasma ghrelin concentration, female sex, heavier birth weight, and lower lamb pre-suckling plasma glucose concentrations. Greater rectal temperatures were associated with heavier birth weight and gestation lengths shorter than 146 d, but no relationship with neonatal behavioral progression was evident. Pre-suckling glucose concentrations were greater in singletons and lambs born to ewes of high BCS at d 95 of gestation, and lambs of heavier birth weight, but were also associated with lower rectal temperatures. This might reflect a delay in glucose utilisation during the adjustment from a fetal metabolic rate to a level appropriate for cold external environments. Singleton lambs exhibited lower pre-suckling plasma NEFA concentrations, and were almost 8 times more likely to survive to 72 h than a twin-born lamb. Birth weight was lesser in lambs born to ewes with high plasma glucose and leptin concentrations prior to lambing, and was positively related to ewe BW at d 95 of gestation and to length of gestation. Greater pre-suckling plasma ghrelin and leptin concentrations were measured for shorter gestation lengths. Neonate pre-suckling ghrelin concentrations above 650 pg/mL tended (P = 0.077) to be associated with improved lamb survival to 72 h. This was consistent with a curvilinear decline in neonate survival rates to 72 h after birth as time latency to suckle increased. No relationship was observed between lamb plasma glucose concentrations and behavioral expression after lambing. Lambs exhibiting greater metabolic and endocrine maturity at birth had improved survival in a cold environment to 72 h after birth. The role of ghrelin in ovine fetal development warrants further investigation.

Genetic parameters for pre-weaning and early growth traits in Berkshire pigs when creep feeding is used

Tomiyama, M., Kanetani, T., Tatsukawa, Y., Mori, H., Oikawa, T. — Fri, 06 Nov 2009 08:41:29 PST

The objective of this study was to find optimal traits for inclusion in selection criteria by estimating genetic parameters for direct genetic, maternal genetic and common environmental effects for growth traits before 60 d of age and the number of teats under an open breeding population, and to evaluate genetic relationships for traits at 60 d of age. Records of 2,344 male and 2,204 female purebred Berkshire pigs were analyzed. For body weight at 14 days of age (W14) and for weaning weight (WW), the heritabilities of direct genetic effect were higher than those of maternal genetic effect. This result is contrary to previous results showing a gradual decrease of maternal genetic effect and an increase of direct genetic effect up to weaning. The positive genetic correlations between direct and maternal genetic effects for W14 and WW are clearly contrary to other reports. This phenomenon seems to be caused by creep feeding started just after the birth of the piglets and maintained throughout the pre-weaning period in this Berkshire population.

Genetic evaluation of Angus cattle for carcass marbling using ultrasound and genomic indicators

MacNeil, M. D., Nkrumah, J. D., Woodward, B.W., Northcutt, S. L. — Fri, 06 Nov 2009 08:41:29 PST

Objectives were to estimate genetic parameters needed to elucidate the relationships of a molecular breeding value for marbling (MBV), intramuscular fat of yearling bulls measured with ultrasound (IMF) and marbling score of harvested steers (MRB), and to assess the utility of MBV and IMF in prediction of breeding value for MRB. Records for MRB (n = 38,296) and IMF (n = 6,594) were from the American Angus Association data base used for national cattle evaluation. There were 1006 records of MBV used in this study. (Co)variance components were estimated with ASREML fitting an animal model with fixed contemporary groups for MRB and IMF similar to those used in the Angus national genetic evaluation. The overall mean was the only fixed effect included in the model for MBV. Heritability estimates for carcass measures were 0.48±0.03, 0.31±0.03, and 0.98±0.05 for MRB, IMF, and MBV, respectively. Genetic correlations of IMF and MBV with MRB were 0.56±0.09 and 0.38±0.10, respectively. The genetic correlation between IMF and MBV was 0.80±0.22. These results indicate the MBV evaluated may yield approximately 20% greater genetic advance when used as an indicator trait for genetic prediction of MRB than IMF. However, neither of these indicators alone provides sufficient information to produce highly accurate prediction of breeding value for the economically relevant trait MRB. Given the goal of highly accurate prediction of true breeding value for MRB, results of this work point to the need to continue 1) progeny testing and 2) increasing the genetic correlation between the MBV and MRB.

Prediction of prion protein genotype and association of this genotype with lamb performance traits of Suffolk sheep

Sawalha, R. M., Villanueva, B., Brotherstone, S., Rogers, P. L., Lewis, R. M. — Fri, 06 Nov 2009 08:41:28 PST

The association of the prion protein (PrP) gene with susceptibility to scrapie has formed the basis of selection programs aimed at eradicating the disease from sheep populations. Animals are genotyped for the PrP gene and those with the less susceptible genotypes are selected. The objectives of this study were to determine the effectiveness of predicting PrP genotypes using information from relatives and to investigate the association of the PrP genotype with lamb performance traits in Suffolk sheep. Data were obtained from a scrapie affected flock maintained in Scotland. There were 643 animals genotyped at codon 171 of the PrP gene with 2 alleles, R and Q. The genotypes of these animals were utilized to predict the genotypes of 5,173 non-genotyped animals in the same flock using segregation analysis. The genotype of non-genotyped animals was predicted from the probabilities for each possible genotype; further, an overall index for each animal was calculated to reflect the accuracy of prediction. Association analyses of the PrP gene (using both animals with known and inferred genotypes) with weight at birth, at weaning (56 d), and at 150 d, and for backfat and muscle depths at 150 d of age were carried out. A linear mixed model with random direct and maternal additive genetic effects, maternal permanent and temporary environmental effects, and year of birth was tested and the most appropriate model was used for each trait. The expected number of Q alleles carried (from 0 to 2) by each animal was calculated and used in the model as a linear and quadratic covariate to test for associations with possible additive and dominance PrP gene effects, respectively. Results showed that the genotypes of relatively few animals (235) were inferred with certainty (compared with the 5,173 non-genotyped animals). About 25% of the 5,173 predicted genotypes were inferred with a genotype probability index of 50% and over. There was no significant association of PrP gene with any of the performance traits studied (there were no significant additive or dominance effects). Such was the case whether data on animals with known, or both known and predicted genotypes, were considered. It can be concluded that selection for PrP resistant alleles in Suffolk sheep is unlikely to directly affect performance.

Chronic improvement of amino acid nutrition stimulates initiation of global mRNA translation in tissues of sheep without affecting protein elongation

Connors, M. T., Poppi, D. P., Cant, J. P. — Fri, 06 Nov 2009 08:41:28 PST

Initiation of mRNA translation and elongation of the polypeptide chain are two regulated processes responsible for the short-term postprandial acceleration of protein synthesis in animal tissues. It is known that a chronic increase in the absorptive supply of amino acids stimulates protein synthesis in ruminant animals but effects on translation initiation and elongation are unknown. To determine whether initiation or elongation phases of global mRNA translation are affected by chronic elevation of amino acid supply, 24 ewe lambs of 25.9 ± 2.5 kg BW were randomly allocated to 4 treatment groups of 6 lambs each. All lambs received a basal diet of barley and hay at 1.2 times maintenance ME intake. Treatments were an i.v. saline infusion as a control, i.v. infusion of 6 essential amino acids (EAA; Arg, Lys, His, Thr, Met, Cys) for 10 d, i.v. infusion of the same EAA excluding Met and Cys (EAA-SAA) for 10 d, and an oral drench of fishmeal twice daily for 17 d. Fishmeal supplementation supplied an extra 719 mg N•kg^-0.75•d^-1 and N retention was increased 519 mg•kg^-0.75•d^-1 over the control. The EAA treatment supplied an extra 343 mg N•kg^-0.75•d^-1 directly into the blood and N balance was increased by 268 mg•kg^-0.75•d^-1. Deletion of Met plus Cys from EAA had no effect on N balance. The results indicate that Met plus Cys did not limit body protein gain on either the basal diet alone or the basal diet plus six amino acids. Protein fractional synthesis rates in liver, duodenum, skin, rumen, semimembranosus, and LM were measured by a flooding dose procedure using L-[ring-2,6-³H]-Phe. Ribosome transit times were estimated from the ratio of nascent to total protein-bound radioactivities. Fishmeal and EAA treatments had no effect on RNA, DNA, or protein contents of tissues but FSR, translational efficiency, and concentrations of active ribosomes were consistently elevated. Ribosome transit time was not affected by long-term amino acid supply. We conclude that the chronic stimulation of protein synthesis by long-term i.v. infusion of EAA or supplementation with an undegradable protein source is brought about by an improvement in the rate of initiation of mRNA translation with no change in the rate of polypeptide chain elongation.

Effect of bovine respiratory disease and overall pathogenic disease incidence on carcass traits

Garcia, M. D., Thallman, R. M., Wheeler, T. L., Shackelford, S. D., Casas, E. — Fri, 06 Nov 2009 08:41:27 PST

The objective this study was to evaluate the effects of incidence of bovine respiratory disease (BRD) and overall incidence of pathogenic diseases (IPD) on carcass traits. Two independent populations were used; the first population included crossbred steers (GPE7; n = 642) derived from sires of 7 Bos taurus breeds: Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental. The second population included crossbred steers (GPE8; n = 621) derived from tropically adapted Bos taurus breeds and Bos indicus influenced breeds: Beefmaster, Brangus, Bonsmara, and Romosinuano, as well as Hereford and Angus. Treatment records for BRD, infectious keratoconjunctivitis, and infectious pododermatitis were available for these populations. Incidence of BRD was treated as an independent effect. Incidences of the 3 microbial pathogenic diseases were pooled into a single trait to represent an overall pathogenic disease incidence. Traits evaluated were HCW, KPH, LM area, marbling score, fat thickness, dressing percentage, yield grade, retail, fat, and bone yields, and meat tenderness. Both, BRD and IPD were associated with differences in yield grade in GPE7 and GPE8. Animals treated for BRD had lower yield grades (P = 0.003 and P = 0.02, in GPE7 and GPE8, respectively) than untreated animals. Animals treated for IPD had lower yield grades (P = 0.0006 and P = 0.004, in GPE7 and GPE8, respectively) than untreated animals. Incidence of BRD and IPD were associated with a reduction in fat thickness in GPE7 and GPE8. Animals treated for BRD had lower adjusted fat measurements (P = 0.0007 and P = 0.01, in GPE7 and GPE8) than untreated animals. Animals treated for IPD also had lower adjusted fat measurements (P = 0.0003 and P = 0.002, in GPE7 and GPE8) than untreated animals. Animals treated for BRD or IPD in the GPE7 population also had lower estimated KPH measurements than unaffected animals. Animals affected with BRD in GPE8 had higher shear force measurements than unaffected animals. Animals affected with IPD in GPE8 had higher HCW and fat yield measurements, but lower bone yield and retail product yield measurements than unaffected animals. The relationship between disease and carcass traits should be given consideration by future studies that aim to develop selection strategies based on specific traits.

Metabolic and hematological profiles in mature horses supplemented with different selenium sources and doses

Calamari, L., Abeni, F., Bertin, G. — Fri, 06 Nov 2009 08:41:27 PST

This study was conducted to determine the effects of dietary Se source and dose on metabolic and hematological profiles, and their relationships with oxidative status in horses. Twenty-five mature horses were blocked by BW and randomly allocated to 1 of 5 dietary treatments: negative control (CTRL: 0.085 mg Se/kg DM), 3 different dietary concentrations of organic Se provided by Se yeast (SY02, SY03, and SY04 containing 0.2, 0.3, and 0.4 mg total Se/kg DM, respectively), and 1 positive control provided by sodium selenite (SS03 containing 0.3 mg total Se/kg DM). Horses were fed the same basal diet (6 kg of grass hay and 3 kg of concentrate per horse daily) and received their respective treatments for a continuous period of 112 d. Jugular venous blood samples were collected before the morning feed on d 0, 28, 56, 84, and 112. Whole blood was analyzed for hematological profile, and plasma was analyzed for metabolites of energy, protein, and mineral metabolism, enzymatic activities and metabolites related to liver and muscle damage, and markers of inflammatory and oxidative status. Plasma metabolites related to energy, protein, and mineral metabolism, acute phase proteins, and enzyme activities related to hepatocellular, hepatobiliary, and muscle damage were not affected by Se source or dose. There were no differences among treatments in either reactive oxygen metabolites or thiol group concentrations in plasma. However, a linear decrease (P < 0. 01) in plasma total antioxidants was observed with increasing Se yeast supplementation. Furthermore, total antioxidant concentrations were lower in SY03 than SS03 horses (P < 0.05), and were lower in SY03 and SY04 than CTRL horses (P < 0.05). These results could be interpreted as an improvement in the preventive antioxidant systems of horses fed Se yeast. Total white blood cell count was not affected by treatment. There was a tendency for horses receiving greater concentrations of Se yeast to have greater lymphocyte counts (P = 0.09), with greater lymphocyte counts in blood of SY03 vs. SS03 horses (P < 0.05). Despite the lack of effect of Se source and dose on markers of inflammatory and liver status, the hematological profile seems to indicate an immunomodulatory action, as shown by mild changes in the white blood cell populations in response to Se yeast inclusion.

Molecular cloning and characterization of porcine calcinuerin-{alpha} subunit espression in skeletal muscle

Fri, 06 Nov 2009 08:41:27 PST

The calmodulin/Ca²⁺-dependent serine/threonine phophatase, calcineurin (CaN), has been implicated in controlling muscle fiber phenotype. However, little information is available concerning the expression of CaN in porcine skeletal muscle. Therefore, the porcine CaN (CaN-A) was cloned by reverse transcriptase PCR and its expression characterized in selected porcine skeletal muscles. We successfully cloned porcine CaN gene using semitendinosus muscle (GenBank accession number AF193515). Sequence analysis showed both the full length and a 30-bp deletion splice variant in coding region of the gene reported in other species. The deduced amino acid sequence showed 99.4% homology with the rat CaN-A isoform gene. Real time PCR analysis showed CaN is present in all tissues. However, using primers targeting the region containing the 30-bp deletion, the full length sequence is only found in skeletal muscle and brain tissues. Using a CaN-A monoclonal antibody, we localized CaN-A in porcine longissimus and soleus muscles and the red and white portions of the semitendinosus muscle. The CaN-A protein was abundant in fast fibers and primarily localized in the cytoplasm, whereas slow fibers expressed low levels of CaN-A. Further studies are required to understand the functions of CaN-A isoform in skeletal muscle.

Effect of selenium supplementation and plane of nutrition on mares and their foals: Selenium concentrations and glutathione peroxidase

Karren, B. J., Thorson, J. F., Cavinder, C. A., Hammer, C. J., Coverdale, J. A. — Fri, 06 Nov 2009 08:41:36 PST

To investigate maternal plane of nutrition and role of Se yeast on muscle Se concentration, plasma glutathione peroxidase (Gsh-Px) activity, and colostrum Se concentration in mares and their foals, 28 Quarter Horse mares (465 to 612 kg BW, and 6 to 19 yr of age) were used in a study utilizing a randomized complete block design. Mares were blocked by expected foaling date and randomly assigned to dietary treatment within block. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture plus grain mix (fed at 0.75% BW on an as-fed basis) and 2 concentrations of Se yeast supplementation (0 or 0.3 mg/kg DMI), resulting in 4 treatments: pasture (P), pasture + grain mix (PG), pasture + grain mix + Se (PGS), or pasture + Se (PS). Mares fed diets P and PS received approximately 100% of the calculated 2007 NRC DE requirements, while PG and PGS received 120%. Selenium supplementation began 110 d prior to estimated foaling date and treatments were terminated at parturition. Blood and muscle (biopsy) samples were collected on d 0 and then every 14 or 28 d, respectively, thereafter until parturition. Additionally, BW, BCS, and rump fat (RF) were recorded every 14 d. At parturition, colostrum, foal plasma, and muscle samples were collected and sampling continued every 14 d for plasma and 28 d for muscle until d 56. Mare BW, BCS, and RF were affected by plane of nutrition (P ≤ 0.02) but not by Se supplementation. Mares fed grain mix had greater (P < 0.05) BW, BCS, and RF measurements throughout the experiment. Mare plasma, muscle, and colostrum Se concentrations were greater (P < 0.01) in mares fed Se. Mares fed grain mix had greater plasma Se (P = 0.02) than mares on pasture alone. Mare and foal plasma Gsh-Px concentrations were not affected by treatment. Foal plasma and muscle Se concentrations were greater when dams were fed supplemental grain mix (P = 0.04 and 0.02, respectively) and supplemental Se (P < 0.001). Results indicated that maternal plane of nutrition and Se supplementation affect mare and foal plasma, muscle, and colostrum Se concentrations but not Gsh-Px activity.

Effect of selenium supplementation and plane of nutrition on mares and their foals: Foaling data

Fri, 06 Nov 2009 08:41:35 PST

To investigate maternal plane of nutrition and role of Se yeast on foaling variables and passive transfer of immunoglobulin G (IgG), 28 Quarter Horse mares were used in a study utilizing a randomized complete block design. Mares were blocked by expected foaling date and assigned randomly within block to dietary treatments. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture plus grain mix (fed at 0.75% BW on an as-fed basis) and 2 concentrations of Se yeast (0 or 0.3 mg/kg DMI). This resulted in 4 treatments: pasture (P), pasture + Se (PS), pasture + grain mix (PG), and pasture + grain mix + Se (PGS). Assuming DMI at 2% BW, the P and PS mares received approximately 100% of calculated 2007 NRC DE requirements, while PG and PGS received 120%. Selenium supplementation began 110 d prior to the estimated foaling date and all dietary treatments were terminated at parturition. At parturition, foaling variables were recorded. Additionally, placental weight was recorded and 2 samples from each placenta were collected for analysis of DNA, RNA, and protein. Colostrum was obtained for fat, protein, milk urea nitrogen (MUN), somatic cell count (SCC), and IgG analyses. Foal blood samples were collected at 0, 6, 12, 18, and 24 h after parturition for IgG analysis. There was no effect of Se or plane of nutrition on foaling variables; however, foal BW as a percentage of mare BW tended (P = 0.10) to be reduced in foals from mares on grain mix (PG and PGS; 7.6%) compared to mares not fed grain mix (P and PS; 8.0%). There was also no effect of Se or plane of nutrition on placental cell number (mg DNA/g), potential cellular activity (RNA/DNA), expulsion time, or weight. However, mares fed supplemental Se (PS and PGS) had decreased (P = 0.02) placental cell size (24.1 mg protein/mg DNA) compared to mares not fed supplemental Se (P and PG; 32.5 mg protein/mg DNA). There was also no effect of Se or plane of nutrition on colostral fat, protein, MUN, or SCC. However, mares fed grain mix (PG and PGS) had lower (P = 0.03) colostral IgG (76.5 g/L) compared to mares not fed grain mix (P and PS; 126.6 g/L). Foals from mares fed grain (PG and PGS) tended (P = 0.06) to have lower overall serum IgG (13.6 g/L) compared to foals from mares not fed grain (P and PS; 15.3 g/L). These data indicate that maternal diet during the last third of gestation affects placental efficiency and colostral IgG.

The relevance of purebred information for predicting genetic merit of survival at birth of crossbred piglets

Cecchinato, A., de los Campos, G., Gianola, D., Gallo, L., Carnier, P. — Fri, 06 Nov 2009 08:41:26 PST

The objective of this study was to infer (co)variance components for piglet survival at birth in purebred (P) and crossbred (C) pigs. Data were from 13,643 (1,213 litters) C and 30,919 (3,162 litters) P pigs, produced by mating the same 168 P boars to 460 Large White-derived crossbred females and 1,413 P sows, respectively. The outcome variable was piglet survival at birth as a binary trait. A Bayesian bivariate threshold model was implemented via Gibbs sampling. Flat priors were assigned to the effects of sex, parity of the dam, litter size and year-month of birth. Gaussian priors were assigned to litter, dam and sire effects. Marginal posterior means (SD) of the sire and dam variances for liability of piglet survival in P were 0.018 (0.008) and 0.077 (0.020), respectively. For C, sire and dam variance estimates were 0.030 (0.018) and 0.120 (0.034), respectively. The posterior means (SD) of the heritability of liability of survival in P and C and of the genetic correlation between these traits were 0.049 (0.023), 0.091 (0.054), and 0.248 (0.336), respectively. The highest 95% confidence region (-0.406, 0.821) for the genetic correlation between P and C liabilities of piglet survival included zero. Results suggest that the expected genetic progress for piglet survival in C when selection is based on P information may be nil.

Feed intake of sheep as affected by live weight, breed, sex and feed composition

Lewis, R. M., Emmans, G. C. — Fri, 06 Nov 2009 08:41:26 PST

The hypotheses tested were that genetic size-scaling for mature BW (A, kg) would reduce variation in intake between kinds of sheep, and that quadratic polynomials on u = BW/A with zero intercept would provide good descriptions of the relationship between scaled intake (SI, g/A^0.73 d) and degree of maturity in BW (u) across feeds of differing quality. Both sexes of Suffolk sheep from two experimental lines (n 225), and from three breed types (Suffolk, Scottish Blackface and their cross; n 149), were recorded weekly for ad libitum feed intake and BW; recording of intake was from weaning through, in some cases, near maturity. Six diets of different quality were fed ad libitum. The relationship between intake and BW on a given feed varied considerably between kinds of sheep. Much, but not all, of that variation was removed by genetic size-scaling. In males, the maximum value of SI was higher than in females (P < 0.07), and was greater in Suffolk than in Scottish Blackface, with the cross intermediate (P = 0.025); there was no difference between the two Suffolk lines used (P = 0.106). The quadratic polynomial model, through the origin, was compared with a split-line (spline) regression for describing how SI varied with u. For the spline model, the intercept was not different from zero in any case (P > 0.05). The values of u at which SI achieved its maximum value (u* and SI*) were calculated. Both models fit the data well; the quadratic was preferred because it predicted that SI* would be achieved within the range of the long run data, as was observed. On a high quality food, for the spline regression, u* varied little around 0.434 (SD 0.020) for the ten different kinds of sheep used. For the quadratic, the mean value of 0.643 (SD 0.066) was more variable, but there were no consistent effects of kind of sheep. The values of u* and SI* estimated using the quadratic model varied among the six feeds: 0.643 and 78.5 on high quality; 0.760 and 79.6 on medium protein content; 0.859 and 73.3 on low protein content; 0.756 and 112 on a low energy content feed; 0.937 and 107 on Ryegrass; and, 1 (forced, as the fitted value of 1.11 was infeasible) and 135 on Lucerne. The value of u* tended to increase as feed digestibility decreased. We conclude that genetic size-scaling of intake is useful, and that a quadratic polynomial with zero intercept provides a good description of the relationship between SI and u for different kinds of sheep on feeds of different quality. Up to u 0.45, intake was directly proportional to BW.

Covariance functions for weights from birth to maturity in Nellore cows

Boligon, A. A., Mercadante, M. E. Z., Forni, S., Lobo, R. B., Albuquerque, L. G. — Fri, 06 Nov 2009 08:41:25 PST

The objective of this study was to estimate (co)variance functions using random regression models on Legendre polynomials for the analysis of repeated measures of weight from birth to adult age. A total of 82,064 records from 8,145 females were analyzed. Different models were compared. The models included additive direct and maternal effects, and animal and maternal permanent environmental effects as random terms. Contemporary group and dam age at calving (linear and quadratic effect) were included as fixed effects, and orthogonal Legendre polynomials of animal age (cubic regression) were considered as random covariables. Eight models with polynomials of third- to sixth-order were used to describe additive direct and maternal effects, and animal and maternal permanent environmental effects. Residual effects were modeled using either one (i.e., assuming homogeneity of variances across all ages) or five age classes. The model with five classes was the best to describe the trajectory of residuals along the growth curve. The model including fourth- and sixth-order polynomials for additive direct and animal permanent environmental effects, respectively, and third-order polynomials for maternal genetic and maternal permanent environmental effects were the best. Estimates of (co)variance obtained with the multi-trait and random regression models were similar. Direct heritability estimates obtained with the random regression models followed a trend similar to that obtained with the multi-trait model. The largest estimates of maternal heritability were those of weights taken close to 240 d of age. In general, estimates of correlation between weights from birth to 8 yr of age decreased with increasing distance between ages.

Impacts of amino acid nutrition on pregnancy outcome in pigs: mechanisms and implications for swine production

Fri, 23 Oct 2009 10:02:47 PDT

Pigs suffer up to 50% embryonic and fetal loss during gestation and exhibit the most severe naturally occurring intrauterine growth retardation among livestock species. Placental insufficiency is a major factor contributing to suboptimal reproductive performance and low birth weights of pigs. Enhancement of placental growth and function through nutritional management offers an effective solution to improving embryonic and fetal survival and growth. We discovered an unusual abundance of the arginine family of AA in porcine allantoic fluid (a reservoir of nutrients) during early gestation when placental growth is most rapid. Arginine is metabolized to ornithine, proline, and nitric oxide, and these compounds possess a plethora of physiological functions. Importantly, nitric oxide is a vasodilator and angiogenic factor, whereas both ornithine and proline are substrates for placental synthesis of polyamines that are key regulators of protein synthesis and angiogenesis. Additionally, arginine, leucine, glutamine, and proline activate the mammalian target of rapamycin cell signaling pathway to enhance protein synthesis and cell proliferation in placentae. To translate basic research on AA biochemistry and nutrition into application, dietary supplementation with 0.83% L-arginine to gilts on d 14 to 28 or d 30 to 114 of gestation increased the number and litter birth weight of live-born piglets. Also, supplementing the gestation diet with 0.4% L-arginine plus 0.6% L-glutamine enhanced efficiency of nutrient utilization, reduced variation in piglet birth weight, and increased litter birth weight. By regulating syntheses of nitric oxide, polyamines and proteins, functional AA stimulate placental growth and the transfer of nutrients from mother to embryo/fetus to promote conceptus survival, growth and development.

Potential of low temperature anaerobic digestion to address current environmental concerns on swine production

Masse, D. I., Masse, L., Xia, Y., Gilbert, Y. — Fri, 23 Oct 2009 10:02:46 PDT

Environmental issues associated with swine production are becoming a major concern within the general public, and thus an important challenge for the swine industry. There is now a renewed interest in environmental biotechnologies that can minimize the impact of swine production and add value to livestock by-products. An anaerobic biotechnology called Psychrophilic Anaerobic Digestion in Sequencing Batch Reactors (PAD in SBR) has been developed at Agriculture and Agri-Food Canada. This highly stable biotechnology recovers usable energy, stabilizes and deodorizes manure, and increases the availability of plant nutrients. Experimental results indicated that PAD of swine manure slurry at 15°C to 25°C in intermittently-fed SBR reduces the pollution potential of manure by removing up to 90% of the soluble chemical oxygen demand (SCOD). The process performs well under intermittent feeding, once to three times a week, and without external mixing. Bioreactor feeding activities can thus be easily integrated to the routine manure removal procedures in the barn, with minimum interference on other farm operations and using existing manure handling equipment. Process stability was not affected by the presence of antibiotics in manure. The PAD process was efficient in eliminating populations of zoonotic pathogens and parasites present in raw livestock manure slurries. Psychrophilic anaerobic digestion in SBR could also be used for swine mortality disposal. The addition of swine carcasses, at loading rates representing up to 8 times the normal mortality rates on commercial farms, did not affect the stability of SBR. There was no operational problem related to the formation of foam and scum. The biotechnology was successfully operated at semi-industrial and full commercial scales. Biogas production rate exceeded 0.20 l of CH₄ per gram of total chemical oxygen demand (TCOD) fed to the SBR. The biogas was of high quality with a methane concentration ranging from 70% to 80%. The recovery of green energy, the production of a value added odorless fertilizer, the elimination of manure pathogens, and the proper disposal of swine mortalities will substantially reduce the carbon and environmental footprints on products of swine origin.

Effect of electron beam irradiation and storage on the quality attributes of sausages with different fat contents

Kwon, J. H., Nam, K. C., Lee, E. J., H, Kang, J., Ahn, D. U. — Fri, 23 Oct 2009 10:02:46 PDT

Sausages with different fat contents (16%, 29%) were purchased from local stores, vacuum-packaged in oxygen-impermeable bags, and irradiated at 0 or 5 kGy using a linear accelerator. The changes in quality attributes of irradiated sausages were determined during storage at 4 °C. The 2-thiobarbituric acid reactive substances (TBARS) value of sausages was not affected by fat content, but increased after irradiation (5 kGy). Storage for 60 days increased the TBARS of nonirradiated sausages (P < 0.05), but had no effect on irradiated ones. The numbers of volatile compounds and the amounts of total volatiles increased by irradiation in both high-fat (29% fat) and low-fat (16% fat) sausages. Dimethyl sulfide was detected only in irradiated sausages regardless of fat content (P < 0.05), but disappeared after 60 days of storage. Pentane and 1-heptene were detected only in irradiated samples after 60 days of storage. Low-fat sausages had higher L*-value, but had lower a*- and b*-values than high fat sausages. Irradiation and storage had little effects on both the exterior and interior color (L*-, a*-, and b*-values) of sausages. Fat content had no effect on the sensory parameters of sausages regardless irradiation and storage. However, irradiated sausages had significantly stronger off-odor and off-taste than non-irradiated ones regardless of fat contents (P < 0.05). This indicated that fat content in sausages had minimal effects on the quality of irradiated sausages during storage.

Use of chitosans to modulate ruminal fermentation of a 50:50 forage-to-concentrate diet in sheep

Goiri, I., Oregui, L. M., Garcia-Rodriguez, A. — Fri, 23 Oct 2009 10:02:45 PDT

The objective of this study was to investigate the effects of chitosan on ruminal and cecal fermentation, and apparent digestibility in sheep. In a first trial, four ruminally fistulated sheep fed an alfalfa hay and concentrate diet formulated to meet 1.2 times their maintenance energy requirements were assigned to two treatments (no-additive control: CTR; 136 mg/kg BW of chitosan: CHI) in a 2 x 2 19-d crossover design. Samples of ruminal fluid and feces were taken for VFA and ammonia-N (NH₃-N) concentrations. At the end of each period of the crossover, ruminal fluid was used as inoculum for batch cultures (24 and 96 h), and the effects on rate and extent of gas production and fermentation parameters for starch, cellulose, and the same diet fed to the animals were calculated. In a second trial, four sheep fed the alfalfa hay and concentrate diet were assigned to two treatments (CTR and CHI) as for the first trial, this time in a 2 x 2 14-d crossover design. Apparent digestibility was studied. In the first trial, in terms of ruminal fermentation, CHI did not affect total VFA concentration or acetate proportion, but increased propionate proportion and propionate-to-acetate ratio (C3:C2), and decreased branch-chained VFA (BCVFA) proportion and NH₃-N concentration. In feces, CHI decreased total VFA concentration and acetate and butyrate proportions, and increased propionate, valerate, and BCVFA proportions and C3:C2 ratio. In batch cultures, when starch was used as substrate, CHI decreased acetate proportion and methane production, and increased propionate and valerate proportions and C3:C2 ratio. When cellulose was used as substrate, CHI decreased in vitro organic matter digestibility, total VFA concentration, propionate proportion, C3:C2 ratio, methane production, NH₃-N concentration, and gas production rate, and increased butyrate and BCVFA proportions and pH. When the alfalfa hay and concentrate diet was used as substrate, CHI decreased butyrate and BCVFA proportions, methane and asymptotic gas production, and gas production rate. In the second trial, CHI decreased NDF apparent digestibility. In conclusion, CHI shifted ruminal fermentation toward energetically more efficient routes, without reducing OM apparent digestibility.

Engaging science in a climate of values: tools for animal scientists tasked with addressing ethical problems

Croney, C. C., Anthony, R. — Fri, 23 Oct 2009 10:02:45 PDT

In the United States, escalating concerns about current farm animal science and production methods have resulted not just in increased food animal protectionpolicies, but also, in animal welfare legislation. Animal scientists and industry leaders are apprehensive that such policies may primarily be driven by emotion and lack of scientific understanding, and thus, may have unforeseenconsequences. However, decisions about animal care and particularly, animal welfare cannot be made solely on the basis of science because the potential impacts on producers, animals, concerned citizens, and implications for the environment and food prices must also be considered. Balancing the interests and values of all stakeholders in regard to animal welfare problems has presenteda considerable challenge. Ethical accounting processes, such as the Ethical Matrix and Campbell’s ethics assessment process offer models to combine socio-ethical concerns with relevant factual information, thereby facilitating decision-making that is both ethically responsible and offers viable solutions. A case study is used to illustrate application of Campbell’s ethics assessment process, which includes identification of the ethical problems, the embedded values, the relevant facts and moral tests that can be applied. Awareness of these emerging ways of doing ethics that offer real solutions to conflicts of interests and not merely ‘one size fits all’ answers should be an asset to animal and poultry scientists.

Epigenetics and fetal adaptation to perinatal events: Diversity through fidelity

Fri, 23 Oct 2009 10:02:45 PDT

Perinatal insults, including fetal under-nutrition and hypoxia, are associated with an increased susceptibility to a number of adult onset metabolic disorders. These include cardiovascular disease, insulin resistance and obesity. However, the mechanisms driving the long-term phenotypic consequences are only recently being elucidated. A primary mechanism accounting for perinatal adaptation is the epigenetic modification of chromatin. In this context, epigenetic modifications to chromatin are thought to arise in response to a perinatal insult in an effort to modulate gene expression and maximize fetal survival. In this symposium report, we discuss epigenetics as a mechanism by which perinatal adaptations can be made by the developing fetus. We examine the benefits of using multiple in vivo models to understand the interrelation of signals that come together and result in perinatal adaptation. Epigenetic effects on IGF-1 arising from a perinatal insult are discussed, as are the difficulties and challenges associated with this complex field. In conclusion, epigenetics provides a means of modulating gene transcription; thus allowing fetal adaptation to a broad variety of conditions.

Effects of ruminal protein degradability and frequency of supplementation on nitrogen retention, apparent digestibility, and nutrient flux across visceral tissues in lambs fed low-quality forage

Atkinson, R. L., Toone, C. D., Robinson, T. J., Harmon, D. L., Ludden, P. A. — Fri, 23 Oct 2009 10:02:44 PDT

Two experiments were conducted to determine the effect of ruminal protein degradability and supplementation frequency on intake, apparent digestibility, N retention, and nutrient flux across visceral tissues of lambs fed a low-quality forage diet. In both experiments, wethers were fed a basal diet of mature crested wheatgrass hay (4.2% CP) for ad libitum consumption plus 1 of 4 supplements: 1) a high ruminally degradable protein (RDP) supplement provided daily (RDP-D), 2) the high RDP supplement provided on alternate d (RDP-A), 3) a high ruminally undegradable supplement (RUP) provided on alternate d (RUP-A), or 4) a 50:50 mixture of the RDP and RUP supplements provided on alternate d (MIX-A). In Exp. 1, 12 lambs (29.9 ± 2.7 kg initial BW) were used. Forage OM, NDF, and ADF intake were not affected by treatment. Total tract digestibilities (OM, NDF, ADF, and N) were unaffected by treatment. Neither protein degradability nor supplementation frequency had an effect on N retention. In Exp. 2, 15 lambs (34 ± 4 kg initial BW) fitted with indwelling catheters were used. Release of ammonia N by the portal-drained viscera (PDV) was reduced (P = 0.004) in alternate day supplemented lambs compared with RDP-D. Consequently, hepatic uptake of ammonia N was least (P = 0.003) in all alternate-day lambs. Alpha-amino nitrogen (AAN) release by the PDV and hepatic uptake of AAN were not affected by treatment or supplementation frequency. Additionally, hepatic output and PDV uptake of urea N were not affected by treatment. Hepatic N uptake (ammonia N + AAN) accounted for urea synthesized by the liver in all treatments; however, hepatic urea synthesis was approximately 4.5 fold less for RUP-A lambs. This suggests that the provision of amino acids as RUP may provide a delay in ureagenesis, thus altering the timing of N recycling.

Effects of ruminal protein degradability and frequency of supplementation on site and extent of digestion and ruminal fermentation characteristics in lambs fed low-quality forage

Atkinson, R. L., Toone, C. D., Ludden, P. A. — Fri, 23 Oct 2009 10:02:44 PDT

Four ruminally and duodenally cannulated Suffolk wether lambs (34.5 ± 2.0 kg initial BW) were used in a 4 x 4 Latin square designed experiment to examine the effects of ruminal protein degradability and supplementation frequency on site and extent of digestion in lambs consuming a low-quality forage diet. Wethers were fed a basal diet of mature crested wheatgrass hay (4.2% CP) for ad libitum consumption plus 1 of 4 supplements: 1) a high ruminally degradable protein (RDP) supplement provided daily (RDP-D), 2) the high RDP supplement provided on alternate d (RDP-A), 3) a high ruminally undegradable protein (RUP) supplement provided on alternate d (RUP-A), or 4) a 50:50 mixture of the RDP and RUP supplements, provided on alternate d (MIX-A). Forage OM, N, NDF, or ADF intakes were not affected by treatment. True ruminal OM digestibility was greater (P < 0.001) for MIX-A lambs compared with other treatments. True ruminal N digestibility was lower (P < 0.01) in RUP-A lambs compared with other treatments. Ruminal digestibilities of NDF and ADF were greater (P ≤ 0.01) for MIX-A lambs compared to other treatments. There was a treatment x hour interaction (P < 0.001) with a delay in peak concentrations within the RDP-A lambs. However, lambs supplemented with RUP had lower (P < 0.001) ruminal ammonia concentrations compared to RDP-D lambs, with RUP-A lambs exhibiting the lowest concentrations and least variation over time. Ruminal urease activity was not affected by treatment. Microbial N flow was not affected by treatment; however, there was an increase (P = 0.004) in microbial efficiency for RDP-D lambs. Alternate day protein supplementation with a mixture of RDP and RUP may improve digestibility in lambs consuming low-quality forage, which may be related to decreased fluctuation in ruminal ammonia concentrations as a result of greater endogenous N recycling.

Effects of Twin Pregnancy and Dry Period Feeding Strategy on Milk Production, Energy Balance, and Metabolic Profiles in Dairy Cows

Silva-del-Rio, N., Fricke, P. M., Grummer, R. R. — Fri, 23 Oct 2009 10:02:44 PDT

The present study evaluated the interaction of pregnancy type (PT) [single (S) vs. twin (T)] and dry period feeding management (D) [close-up (CU) diet (NEL = 1.54 Mcal/kg DM) throughout the entire dry period (8W) vs. far-off (FO) diet (NEL = 1.32 Mcal/kg DM) from 60 to 21 d prior to expected calving date (ECD) followed by CU diet until calving (3W)]. Treatments were arranged in a 2x2 factorial with a randomized block design with primiparous (n = 8) and multiparous (n = 39) Holstein cows. We hypothesized that increasing the duration of feeding a close-up diet would improve metabolic status and lactation performance for cows with T, but not for cows with S. All cows were fed similarly in late lactation (90 to 60 d before ECD; diet NE_L= 1.58 Mcal/kg DM) and in early lactation (calving to 105 DIM; diet NE_L= 1.71 Mcal/kg DM). Prepartum, DMI as % of BW did not differ with D but tended to be greater for cows with S than with T. Cows with T tended to have greater BW than cows with S, but conceptus-free BW was less for cows with T than for cows with S. No differences were detected in prepartum BCS or BCS change with PT or D. Energy balance (EB) was greater for cows with S than with T, and for cows fed 8W vs. 3W. Cows with T had greater NEFA and a tendency for greater liver triglyceride (TG) and plasma β-hydroxybutyrate (BHBA) than cows with S. Prepartum, cows fed 3W had greater liver TG and plasma NEFA, but lower plasma BHBA than cows fed 8W. Plasma glucose and liver glycogen were less for cows with T but were not affected by D. Postpartum, there was no effect of PT or D on mean DMI as % of BW, BW, and BCS, but there was an interaction of PT x D for mean BCS. Cows that calved T were in a more positive EB than cows that calved S. Milk production was 5.2 kg/d greater for cows fed 8W; however, they were in lower EB than cows that received 3W. Postpartum, cows that calved T had lower concentrations of plasma NEFA and liver TG but greater concentrations of plasma glucose than cows that calved S. Plasma BHBA and NEFA tended to be greater for cows that received 8W than 3W. Neither PT nor D affected plasma glucose and liver glycogen. There was a tendency for an interaction of PT x D for plasma NEFA and liver TG. In contrast to our hypothesis, response to D was independent of pregnancy type. Based on milk production data from the present experiment, 8W is a more desirable feeding strategy than 3W.

Technical note: Comparison of salivary and serum cortisol concentrations after ACTH challenge in ewes

Yates, D. T., Ross, T. T., Hallford, D. M., Yates, L. J., Wesley, R. L. — Fri, 23 Oct 2009 10:02:43 PDT

An ACTH challenge was conducted to determine if salivary cortisol concentration reflects serum cortisol concentration in ewes. Twelve yearling ewes (64.0 ± 1.2 kg) were administered ACTH (100 IU, i.v.) or saline. Serum and salivary samples were collected at 30-min intervals for 2 h before ACTH administration, at 15-min intervals for 2 h after treatment, and at 30-min intervals for an additional 3 h, and cortisol concentration was determined (RIA). Although ewes responded to both ACTH and saline, cortisol concentration was greater (P < 0.001) in ACTH-treated ewes from 15 to 120 min and tended to be greater (P = 0.054) at 150 min after challenge in serum. In saliva, cortisol concentration was greater (P < 0.001) in ACTH-treated ewes from 30 to 120 min and tended to be greater (P = 0.092) at 15 min after challenge. No difference was observed between ACTH-treated ewes and controls for time to peak serum cortisol concentration (P = 0.126) and time to peak salivary cortisol concentration (P = 0.109), or between saliva and serum for time to peak cortisol concentration (P = 0.220) and return to baseline cortisol concentration (P = 0.341). Both serum (P = 0.009) and salivary (P = 0.050) cortisol areas under the curve between 0 and 150 min were greater for ACTH-treated ewes than controls, and serum (P = 0.002) and salivary (P < 0.001) cortisol return to baseline concentration was longer for ACTH-treated ewes. The correlation coefficient between serum and salivary cortisol concentrations was 0.88 (P < 0.001). These data indicate that salivary cortisol concentration is closely related to serum cortisol concentration and that the former may represent a suitable noninvasive alternative to blood collection for measurement of cortisol in sheep.

Effect of dam and sire genotypes on productive and carcass traits of rabbits

Fri, 23 Oct 2009 10:02:43 PDT

The aim of the experiment was to study the effect of dam and sire genotypes on the production and slaughter performance of growing rabbits. The experiment was carried out at the Kaposvár University. Pannon White (P) and Maternal line (M) does were inseminated with the sperm of P, M, Large body line (L), Terminal line of Hycole hybrid (H), or Colored line (C) bucks. The mature body size of the M, P and C genotypes was medium. The mature body size of the L and H genotypes was large. Only P and L rabbits were selected for carcass traits based on Computer tomograph (CT) scanning data. The rabbits (n = 320) were weaned at the age of 5 wk and housed in a closed climate controlled rabbitry in wire cages. Rabbits were fed ad libitum a commercial pellet. Rabbits were slaughtered at 78 d of age. Daily weight gain (5.7%, P < 0.001) and gain-to-feed ratio (G:F) (6.2%, P < 0.001) of the P does’ progeny were better than those of the M does’ progeny. The weight of the chilled carcass and body parts was greater for the progeny of the P does (P<0.001). The ratio of the hind part compared to the reference carcass was higher in the P group (P<0.001); however, the ratio of the fore part was higher in the M group (P<0.05). Examining the effect of sires’ genotype, the body weight and daily weight gain were higher in groups H and L, whereas the progeny of M and C sires were inferior (P<0.05). Body weights at 11 wk of age were: H: 2,918 g, L: 2,793 g, P: 2,678 g, C: 2,636 g, and M: 2,585 g (P < 0.001). Similar differences were found for daily feed intake (P<0.05). G:F differed significantly between groups H and C. The weights of the chilled carcass and of the body parts were the highest for the progeny of the H sires, and the smallest in the M group. The differences between the groups’ dressing out percentages were not significant. The ratio of the fore part was higher in groups L, H, and C, but the ratio of the middle part was not different. The ratio of hind part related to the reference carcass was largest in progeny of P and lowest in L and C groups (P<0.05). It was concluded that the production of growing rabbits was affected by the adult weight of their sires, but the carcass traits were influenced by their own adult weight and by the CT based selection.

Evidence for parent-of-origin effects on genetic variability of beef traits

Neugebauer, N., Rader, I., Schild, H. J., Zimmer, D., Reinsch, N. — Fri, 23 Oct 2009 10:02:43 PDT

Imprinted genes are involved in many aspects of development in mammals, plants and perhaps birds and may play a role in growth and carcass composition of slaughter animals. In the presence of genomic imprinting the expression and, consequently, the effect on the phenotype of maternal and paternal alleles is different. For genetic evaluation genomic imprinting can be accounted for by incorporating two additive genetic effects per animal, the first corresponds to a paternal and the second to a maternal expression pattern of imprinted genes. This model holds whatever the mode of imprinting may be: paternal or maternal, full or partial, or any combination thereof. A set of slaughter data from 65,233 German Simmental fattening bulls was analysed with respect to the relative importance of the genetic imprinting variance. Besides of slaughter weight, net daily gain and killing out percentage there were 22 other traits describing the carcass composition. The latter traits were evaluated by automatic video-imaging (VIA) devices and comprised weights of valuable cuts as well as fat- and meatiness grade. The number of ancestors in the pedigree was 356,880. Genomic imprinting significantly contributed to the genetic variance of ten traits, with estimated proportions between 8% and 25% of the total additive genetic variance. For six of these traits the maternal contribution to the imprinting variance was larger than the paternal while for all other traits the reverse was true. Fat grade only showed a paternal contribution to the imprinting variance. Estimates of animal model heritabilities of VIA-recorded carcass traits ranged between 20% and 30%.

A multilevel nonlinear mixed-effects approach to model growth in pigs

Strathe, A. B., Danfaer, A., Sorensen, H., Kebreab, E. — Fri, 23 Oct 2009 10:02:42 PDT

Growth functions have been used to predict market weight of pigs and maximize return over feed costs. This study was undertaken to compare 4 growth functions and methods of analyzing data, particularly 1 that considers nonlinear repeated measures. Data were collected from an experiment with 40 pigs maintained from birth to maturity and their weight measured weekly or biweekly up to 1,007 d. Gompertz, Logistic, Bridges and Lopez functions were fitted to the data and compared using information criteria. For each function, a multilevel nonlinear mixed effects model was employed because it allowed for estimation of all growth profiles simultaneously and different sources of variation (i.e., gender, pig and litter effects) were incorporated directly into the parameters. Furthermore, variance in-homogeneity and within-pig correlation were introduced to the functions. Inclusion of a variance of power function and a continuous autoregressive process of first order rendered a substantially improved fit to data for all 4 growth functions. The Lopez function provided the best fit to the data set and was used for characterizing mean growth curves for the 3 genders (barrows, boars and gilts). It was estimated that the maximum growth rate occurs at 117, 134 and 96 kg BW for barrows, boars and gilts, respectively. Hence, the gilts reached their maximum growth rate at earlier stage in life compared to boars. Mature size of pigs varied systematically with gender and it was estimated to be 466, 537 and 382 kg BW for the barrows, boars and gilts, respectively. These estimates are significantly affected by the duration of the experimental period and it is recommended that future studies looking at estimating the mature size in animals are conducted long enough so that the BW visually stabilizes. Furthermore, studies should consider adding continuous autoregressive process when analyzing nonlinear mixed models with repeated measures.

Low feed intake of lactating primiparous sows is associated with high insulin resistance during the peri partum period and is not modified through supplementation with dietary tryptophan

Mosnier, E., Le Floc'h, N., Etienne, M., Ramaekers, P., Seve, B., Pere, M.-C. — Fri, 23 Oct 2009 10:02:42 PDT

The aim of this experiment was to investigate whether insulin resistance is related to the dietary concentration of Trp and the ADFI of primiparous sows having similar body conditions. Twenty four primiparous sows were catheterized on d 97 of pregnancy. Blood samples were drawn during 3 tests: after the ingestion of 1.5 kg of feed (meal test), after the intravenous infusion of 0.5 g of glucose/kg BW (glucose tolerance test), and during an euglycemic hyperinsulinemic clamp with an infusion rate of 100 ng insulin·kg BW^-1·min^-1. Both tests were performed at 4 stages, i.e. at approximately d 103 and 110 of pregnancy and at d 3 and 10 of lactation. Sows were fed a diet containing 0.16 or 0.26% of total Trp (suboptimal vs. slight excessive Trp supply according to recommendations for lactating sows) from d 104 of pregnancy after the first clamp until weaning. The dietary treatment did not result in differences in ADFI, BW and backfat changes, and growth of piglets during lactation. Plasma Trp concentration was greater for the sows allocated to the slight excessive Trp diet than for the sows allocated to the suboptimal Trp diet (P < 0.05). Plasma glucose, NEFA, and urea profiles during the meal tests were not affected by the dietary treatment. At d 3 of lactation, the insulin concentration at 105 (P = 0.03) and 120 min (P = 0.04) after meal intake was lower for the sows allocated to the slight excessive Trp diet than for the sows allocated to the suboptimal Trp diet. On d 10 of lactation, the glucose half life (P = 0.03) and the time needed to reach 25% of the area under the insulin curve (P = 0.04) during the tolerance test were lower for the sows allocated to the slight excessive Trp diet than for the sows allocated to the suboptimal Trp diet. The glucose infusion rate during euglycemic hyperinsulinemic clamps was similar in the 2 Trp groups of sows. Irrespective of the dietary treatment, the ADFI of the sows was negatively related to the glucose half life during the glucose tolerance test and positively related to the glucose infusion rate during the clamp (P < 0.05). This relationship observed with the tests performed during early lactation was already found with the tests performed during late pregnancy (P < 0.02). Present findings indicate that a dietary Trp supply of 0.26% does not increase feed intake in lactating primiparous sows which questions on the interest in Trp supplementation during the peri partum period. Irrespective of the dietary treatment, the reasons why sows with similar rearing conditions develop different rates of insulin resistance during pregnancy remains to be elucidated.

Pain mitigation following band castration of beef calves and its effects on performance, behavior, E. coli, and salivary cortisol

Fri, 23 Oct 2009 10:02:41 PDT

Eighty-nine steer and bull calves (210 ± 20 d of age) were randomly assigned to a 2 x 2 factorial arrangement of treatments to study the effect of sham or band castration (Cast) with or without pain medication (Med) on performance, behavior, cortisol, and E. coli shedding. Steers (serving as controls; C) were previously castrated at 34 ± 10 d of age whereas bulls (B) remained intact until band application on d 20 of the experiment. One-half of the calves in each group received either pain medication (M; xylazine epidural and i.v. flunixin meglumine) or saline (NM) solutions at 0.5 h prior to castration. Feed intake, ADG and feeding behavior were measured over a 3-wk period prior to (used as covariates), and a 6-wk period after castration. Fecal and saliva samples were collected from 32 calves for E. coli enumeration at -7 (covariate), 2, 5, and 7 d, and for cortisol concentration at -0.5 (covariate), 0, 0.5, 1, 2, 4, 24, 48, 168 and 336 h relative to castration, respectively. Lying behavior was measured in the home pen and step length at exit from the chute. There were no significant Cast x Med interactions on growth rate or feed intake. Overall ADG was lower in B compared to C (P < 0.001) but feed intake was lower during wk 4 only (P = 0.01). On average, M had lower intake (P = 0.02) and eating rate (P = 0.04) than NM calves. The BM had lower fecal E. coli counts than CM (P = 0.05) and BNM calves (P = 0.08). Salivary cortisol was lower in BM compared to the rest of treatments at 1 and 2 h after banding (P ≤ 0.05). Castration reduced time spent lying (P = 0.06) and step length (P = 0.01) until d 28 after banding, whereas M reduced lying and step length on day of banding only (P ≤ 0.06). Significant Cast x Med interactions were observed for frequency of visits to feeders, and meal size, length and frequency (P < 0.05) independent of the time after castration. This was due to greater values in the CNM group compared to the rest, except for reduced meal frequency, indicating that both pain medication and castration affected feeding behavior. The medication protocol used in the present study eliminated the acute cortisol surge, which may be linked to reduced fecal E. coli counts observed during wk 1 after banding. However, feed intake, growth, and behavior suggested that pain was greatest during wk 3 and 4 after band application which highlights the need for chronic pain mitigation strategies.

Effect of dietary protein and lysine fluctuations in the absence and presence of ractopamine on performance and carcass quality of late-finishing pigs

Edmonds, M. S., Baker, D. H. — Fri, 23 Oct 2009 10:02:41 PDT

Two trials with finishing pigs were conducted to evaluate the effects of fluctuating dietary CP levels and ractopamine on performance and carcass traits. In Trial 1, 408 finishing pigs (mixed sex) were assigned to 1 of 4 protein regimens. Average initial and final weights were 89 and 123 kg, respectively. Pigs on treatments 1 to 4 were fed 16, 11, 16 and 13% CP from wk 0 to 2, respectively. During wk 2 to 5, the pigs on regimens 1 to 4 were then fed 15, 18.33, 18 and 20% CP, respectively, with regimens 3 and 4 also containing supplemental ractopamine (9.9 mg/kg) during wk 2 to 5. Overall (wk 0 to 5), gain, gain:feed, loin depth, percentage lean and dressing percent were improved (P < 0.05) in pigs on regimens 3 and 4 vs. those on regimens 1 and 2. No statistically significant overall (wk 0 to 5) protein sequence regimen differences occurred between the standard regimens (1 and 3) and the low-high CP regimens (2 and 4). Trial 2 involved 172 finishing pigs (mixed sex) in 2 protein regimens. Average initial and final weights were 91 and 136 kg, respectively. The diets consisted of: 1) control (16% CP from d 0 to 14, 18% CP + 4.95 mg ractopamine/kg from d 14 to 24, and 18% CP + 9.9 mg ractopamine/kg from d 24 to 35; 2) a low-high CP regimen (12.5% CP from d 0 to 14, 20.33% CP + 4.95 mg ractopamine/kg from d 14 to 24, and 20.33% CP + 9.9 mg ractopamine/kg from d 24 to 35. During d 0 to 14, pigs fed the low CP diet (12.5% CP) had reduced (P < 0.05) gain and gain:feed compared to those fed the control diet (16% CP). In contrast, during d 14 to 35, pigs on the low-high regimen had improved (P < 0.08) gain and gain:feed compared to pigs on the control regimen. Despite the wide dietary CP fluctuations for pigs in Trial 2, performance, and carcass traits were similar for both regimens over the 35-d test period. These data indicate that pigs fed deficient CP and lysine levels for 14 d followed by high CP and lysine levels during a subsequent 21-d period can recover and achieve growth performance and carcass merit equal to that achieved with a conventional protein feeding regimen.

Influence of dietary protein content and source on fecal quality, electrolyte concentrations, and osmolarity, and digestibility in dogs differing in body size

Fri, 23 Oct 2009 10:02:41 PDT

When fed the same diet, large breed dogs tend to produce feces of poorer quality compared with small breed dogs. Moreover, German shepherds, although having a BW similar to Giant Schnauzers, are particularly prone to digestive intolerance, producing feces of poor consistency and high moisture. Digestive tolerance reflects the reaction of the animal to the diet, and it can be assessed by determining fecal quality (consistency, moisture, volume, odor, and color). This study was conducted to assess the effect of protein source and content on fecal quality, and to determine whether greater digestibility and lower fecal osmolarity and electrolyte concentrations are associated with improved fecal quality in dogs differing in body size and digestive tolerance. Twenty-seven healthy female dogs were divided into 4 groups according to BW and digestive tolerance: small, medium, large tolerant, and large sensitive. Five diets, varying in protein source (wheat gluten, poultry meal, and a 50:50 mixture of both sources) and concentration (22, 29, and 39% CP on DM basis for low, medium, and high, respectively) were tested. The present study was divided in 2 phases: 2 diets were studied in a cross-over design in Phase I, and 3 diets in a Latin square design in Phase II. Diets were fed for 14 d followed by a 12-d transition period. Fecal score (1 = dry and hard feces, and 5 = liquid diarrhea), moisture, electrolytes (Na and K), and osmolarity, and digestibility of DM, energy, fat, CP, and ash were determined. Fecal score and moisture (P < 0.001) were lower and overall digestibility (P < 0.001 for DM, CP, fat, ash, and energy) was greater for wheat gluten than poultry meal diets. Large dogs had the highest fecal score and moisture (P < 0.001), together with the greatest overall digestibility (P < 0.001 for DM, P = 0.054 for CP, P = 0.005 for ash, and P = 0.003 for energy). Osmolarity was lower for wheat gluten-based diets (P < 0.001), and was not affected by dog size. Fecal electrolyte concentration varied mainly with dog group (P = 0.005 for Na, and P < 0.001 for K), being greater in large sensitive compared with small dogs. Wheat gluten was proven to be a suitable protein source for modulating fecal quality in dogs, particularly in sensitive breeds. Poorer fecal quality in large sensitive dogs can be related to greater digestibility and greater fecal electrolyte concentrations, but not to fecal osmolarity.

Dose response to cinnamaldehyde supplementation in beef growing heifers: ruminal and intestinal digestion

Yang, W. Z., Ametaj, B. N., Benchaar, C., Beauchemin, K. A. — Fri, 23 Oct 2009 10:02:40 PDT

The objective of this study was to determine if cinnamaldehyde (CIN) could be used to improve feed intake, digestion and immune status in growing beef heifers fed high-concentrate diets. The experiment was designed as a 4 x 4 Latin square using 4 ruminally and duodenally cannulated beef heifers with 4 treatments: control (no CIN added); 400 mg/d CIN (low); 800 mg/d CIN (medium); and 1600 mg/d CIN (high), and four 21-d periods. Feed intake, rumen pH and fermentation characteristics, site and extent of digestion, microbial N synthesis, blood metabolites and acute phase protein response were measured. The diets consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). Intakes (kg/d) of DM, OM, NDF, starch, and N were quadratically (P = 0.04) changed with increasing CIN supplementation. The amount of OM fermented in the rumen quadratically (P = 0.02) decreased with increasing CIN. Digestibilities (% of intake) of OM, NDF and N in the rumen were not affected by supplementing with low and medium CIN, but they were reduced by 8% (P = 0.10), 31% (P = 0.05) and 17% (P = 0.05), respectively, with high CIN. Similarly, digestibilities of OM, and NDF in the total tract also tended to be reduced by 7% (P = 0.10), and 20% (P = 0.10), respectively, with high CIN because supplementation of CIN had minimal effects on intestinal digestibility. Flows (g/d) of microbial N and other nutrients to the duodenum were not affected by CIN supplementation, even though the amount of ruminal fermented OM varied with level of CIN supplementation. Rumen pH, total VFA concentration and molar proportions of individual VFA were not affected by CIN. Although concentrations of NEFA (P = 0.06) and triglyceride (P = 0.01) were quadratically changed with increasing CIN supplementation, blood concentrations of glucose and urea N, white blood cell counts, serum amyloid A and lipopolysaccharide in plasma were not affected by CIN. Plasma haptoglobin numerically (P = 0.11) decreased with the medium dose of CIN fed compared to control. The results indicate that supplementation of a high-concentrate diet with a low dose of CIN resulted in small increases in nutrient availability in the rumen due to increased feed intake and higher ruminal digestion of OM. However, feed intake and ruminal digestion of feeds was adversely affected when a high dose of CIN was used.

A mechanistic model for predicting intake of forage diets by ruminants

Hackmann, T. J., Spain, J. N. — Fri, 23 Oct 2009 10:02:40 PDT

Accurate voluntary feed intake (VFI) prediction is critical to the productivity and profitability of ruminant livestock production systems. Simple empirical models have been used to predict VFI for decades but are inflexible, restrictive, and poorly accommodate many feeding conditions, such as those of developing countries. We have developed a mechanistic model to predict VFI over a range of forage diets (low- and high-quality grasses and legumes) by wild and domestic ruminants of varying physiological states (growth, lactation, gestation, non-productive). Based on chemical reactor theory, the model represents the reticulorumen, large intestine, and blood plasma as continuous stirred-tank reactors and the small intestine as a plug flow reactor. Predicted VFI is that which (i) fulfills an empirical relationship between chemostatic and distention feedbacks observed in the literature and (ii) leads to steady-state conditions. Agreement between observed and actual VFI was high (generally R²> 0.9, root mean square prediction error < 1.4 kg/d, CV < 25%). Root mean square prediction error for our model was only 67% of that of the Beef NRC (2000) model, the leading empirical prediction system for cattle. These results together demonstrate that our model can predict ruminant VFI more broadly and accurately than prior methods and, by consequence, serve as a crucial tool to ruminant livestock production systems.

Redox regulation in skeletal muscle during contractile activity and aging

Palomero, J., Jackson, M. J. — Fri, 09 Oct 2009 07:35:02 PDT

Skeletal muscle has the ability to adapt and remodel following functional, mechanical and metabolic stresses by activation of different adaptation mechanisms which induce gene expression, biochemical changes and structural remodeling. Skeletal muscle cells continuously generate reactive oxygen and nitrogen species (RONS), which can act as mediators in cellular signaling pathways that regulate the adaptation mechanisms. There is strong evidence that indicates that RONS are generated in skeletal muscle cells during contractile activity and this induces the activation of transcription factors which modulate gene expression of antioxidant and protective proteins. Thus, it has been proposed that RONS act as signals that modulate the adaptation mechanisms in skeletal muscle and other cells. Structural and functional changes occur in skeletal muscle during aging and are characterized by a reduction of muscle mass and force (sarcopenia). The causes are known, however, there is considerable support for an involvement of RONS in the process of aging and sarcopenia. Several studies indicate that adaptive responses of skeletal muscle that are activated and regulated by RONS are disrupted during aging. This reduction of skeletal muscle adaptation to contractile activity during aging might be responsible for the loss of muscle mass and function and the progressive deterioration of this organ. In summary, there is sufficient evidence that indicates that cellular redox regulation in skeletal muscle is crucial in the physiology and pathology of skeletal muscle. However, new methodologies and experimental models are required for understanding the complex biology of RONS in the cell. This will provide future interventions that mitigate pathologies and aging of skeletal muscle.

Technical Note: Efficient protocol for isolation of total RNA from lyophilised fat and muscle pig samples

Pena, R. N., Canovas, A., Estany, J. — Fri, 09 Oct 2009 07:35:01 PDT

Isolation of total RNA from frozen muscle and fat samples typically results in low yields due to the presence of connective tissue between muscle fibres, which impairs complete tissue homogenisation, and the excess of fat and low cellularity of adipose tissue. Meat quality studies involve determination of fatty acid composition and content from muscle and subcutaneous fat samples, a process which may produce an excess of lyophilised tissue samples. The purpose of this work was to investigate the stability of total RNA in lyophilised tissue samples generated during the routine detection of fatty acid content of pig muscle and fat tissues, stored either at room temperature or at -20ºC. The protocol described here results in high yields of total RNA from freeze-dried samples stored at -20ºC, which facilitates the homogenisation step. The isolated RNA is suitable for common gene expression techniques such as final point and quantitative reverse transcription-PCR.

Evaluation of the Prediction of Alternative Measures of Pork Carcass Composition by Three Optical Probes

Schinckel, A. P., Wagner, J. R., Forrest, J. C., Einstein, M. E. — Fri, 09 Oct 2009 07:35:01 PDT

The accuracy of three optical probes (HGP4, Hennessey Grading Probe, PG-100 and PG-200) to predict the carcass percentage of five alternative measures of carcass composition: fat tissue-free lean (FFLM), lipid-free soft tissue (LFSTIS), lipid-free lean (LFL), total fat tissue (TOFAT) and soft tissue lipid (STLIP) was evaluated on 203 barrows and gilts of seven genetic populations. The optical probes backfat depths were more greatly correlated (P < 0.001, 0.963 to 0.983) than the LM depths (r = 0.695 to 0.734). The optical probe backfat depths were related to lean percentage (r = -0.82 to -0.88), TOFAT% (r = 0.84 to 0.88) and STLIP% (r = 0.86 to 0.87). Optical probe LM depths were weakly related (P < 0.05; r = 0.23 to 0.34) to measures of carcass lean percentage and TOFAT% (r = -0.16 to -0.26). Fat-free lean percentage was predicted with residual standard deviations (RSD) of 3.7% for equations including last rib midline backfat thickness, 2.4 to 2.7% for equations including optical probe backfat and LM depth, and 2.3% for ribbed carcass measurements. The RSD’s for the optical probe equations ranged from 2.1 to 2.4% for LFSTIS% and 2.0 to 2.3% for LFLEAN%. The RSD’s for the optical probe equations ranged from 2.9 to 3.3% for TOFAT% and 2.5 to 2.8% for STISLIP%. Quadratic and cross-product variables of optical probe fat depth, LM depth and carcass weight were significant (P < 0.05) and reduced the RSD’s of the equations. Optical probe backfat and LM measurements can be used to predict alternative measures of carcass composition. The predicted relationships in FFL% to backfat depth were nearly identical for each optical probe.

Estimates of inbreeding depression for serum insulin-like growth factor I concentrations, body weights, and body weight gains in Angus beef cattle divergently selected for serum insulin-like growth factor I concentration

Davis, M. E., Simmen, R. C. M. — Fri, 09 Oct 2009 07:35:00 PDT

Data for the current study were obtained from a divergent selection experiment in which the selection criterion was the average serum IGF-I concentration of 3 postweaning blood samples collected from purebred Angus calves. Multiple trait derivative-free REML procedures were used to obtain estimates of inbreeding depression for IGF-I concentration and for BW and BW gains measured from birth to the conclusion of a 140-d postweaning performance test. Included in the analysis were 3,243 animals in the A^-1 matrix, 2,182 of which had valid records for IGF-I concentration. Over the course of the entire selection experiment, inbreeding of the calf averaged 3.3% (SD = 3.1%) and inbreeding of the dam averaged 1.8% (SD = 2.7%). Mean inbreeding levels at the end of the study were 6.82 + 0.38% and 4.20 + 0.36% for calves and dams, respectively. Annual rates of increase in inbreeding of calves and dams were 0.36 + 0.01 (P < 0.0001) and 0.25 + 0.01%/yr (P < 0.0001), respectively. Insulin-like growth factor I concentration at d 28 (IGF28), 42 (IGF42), and 56 (IGF56) of the 140-d postweaning test and mean IGF-I concentration decreased by 0.62 + 0.88, 1.86 + 0.96, 1.92 + 0.89, and 1.48 + 0.76 ng/mL per 1% increase in inbreeding of calf. Only the regression coefficient for IGF56 differed significantly from zero, although the regression coefficients for IGF42 and mean IGF-I approached significance (P < 0.10). Increases in inbreeding levels of the dams also tended to result in reduced IGF-I concentrations, although the regression coefficients were not significantly different from zero. Inbreeding of calf had highly significant negative effects on all BW and BW gain traits examined, except for birth weight, with regression coefficients ranging from -0.74 + 0.20 kg/% increase in calf inbreeding for postweaning BW gain to -1.68 + 0.33 kg/% increase in calf inbreeding for off-test BW. Inbreeding of dam had a significant negative effect on birth weight of progeny and tended to have a negative effect on postweaning BW gain (P < 0.10). Preweaning gain of the progeny and BW other than birth weight were not influenced by increases in dam inbreeding. Results indicate that reductions in serum IGF-I concentration due to inbreeding may contribute to the decline in BW and BW gains that is typically associated with increases in inbreeding within populations.

Trait selection and welfare of genetically engineered animals in agriculture

Greger, M. — Fri, 09 Oct 2009 07:35:00 PDT

The release of the Final Guidance from the U.S. Food and Drug Administration on the commercialization of genetically engineered animals has sparked renewed discussion over the ethical, consumer, and regulatory implications of transgenesis in animal agriculture. Animal welfare critiques have focused on unexpected phenotypic effects in animals used in transgenic research, rather than on the health and welfare implications of the intended productivity enhancement. Unless breeding goals are redefined to reflect social concerns, the occurrence and magnitude of undesirable side effects may increase and consumer confidence in the nascent technology undermined.

Characterization of the nutritional value of air-classified protein and starch fractions of field pea and zero-tannin faba bean in grower pigs

Gunawardena, C. K., Zijlstra, R. T., Beltranena, E. — Fri, 09 Oct 2009 07:34:59 PDT

Most pulse (non-oilseed legume) seed flours can be rapidly and economically fractionated by air classification into protein and starch concentrates. The nutritional value of air-classified field pea and faba bean concentrates requires characterization to assess the feeding opportunity for pigs. Thus, the objectives were to characterize the apparent total tract digestibility (ATTD) of DM, OM, energy, starch, CP, fat, and ash, apparent ileal digestibility (AID) of CP and starch, standardized ileal digestibility (SID) of AA, and the SID AA, DE, and NE content of air-classified zero-tannin faba bean and field pea protein and starch concentrates in grower pigs. Pulse protein and starch concentrates were compared to soy protein concentrate and corn starch, respectively, as corresponding standards. The corn starch diet served as an N-free diet to correct for basal endogenous AA losses. In a Youden-square design, 8 ileal-cannulated barrows (24.9 kg ± 2.3 BW) were fed 6 diets over 7 periods at 3 times the maintenance DE requirement. Periods encompassed a 5-d diet acclimation, 3-d feces collection, and 3-d ileal digesta collection. The ATTD of GE was 2% greater (P < 0.05) for faba bean than soy and intermediate for field pea protein (95.6, 93.7, and 94.9%, respectively). The ATTD of GE was 3.6% greater (P < 0.05) for corn and field pea than faba bean starch (96.2, 95.1, and 92.3%, respectively). The DE content of faba bean was 5.0% greater (P < 0.05) than field pea or soy protein (4.47, 4.23, and 4.26 Mcal/kg, respectively). The DE content of faba bean and field pea was 1.7% greater (P < 0.05) than corn starch (3.72, 3.77, and 3.68 Mcal/kg, respectively). The NE content was 5% greater (P < 0.05) for faba bean than field pea and soy protein (3.08, 2.94, and 2.92 Mcal/kg, respectively). The NE content for field pea starch was 2.0% greater (P < 0.05) than for corn starch and faba bean starch (2.68, 2.63, and 2.61 Mcal/kg, respectively). Protein concentrates had a 14 and 11% greater (P < 0.05) DE and NE content than starch concentrates, respectively. The SID of Lys was 6.0% greater (P < 0.05) for faba bean and field pea protein than soy protein (95.5, 92.6, and 88.7%, respectively). The SID of Lys was 6.0% greater (P < 0.05) for faba bean than field pea starch. Nutrient digestibility and digestible nutrient profiles indicate that air-classified fractions of zero-tannin faba bean and field pea constitute concentrated sources of AA and energy for pigs with high nutritional demands.

Pedigree analysis of seven small French sheep populations and implications for the management of rare breeds

Danchin-Burge, C., Palhiere, I., Francois, D., Bibe, B., Leroy, G., Verrier, E. — Fri, 09 Oct 2009 07:34:59 PDT

Pedigree information has been analyzed in 7 small populations of sheep raised in France (Bleu du Maine, Charmoise, Cotentin, on-farm Romanov, Romanov ex situ in vivo, Roussin de la Hague, Solognote), to estimate their genetic variability. The pedigree information for each breed, estimated by the number of equivalent generations traced, ranged from rather poor (4.6) to very good (10.5) when compared with other studies. On the basis of probabilities of gene origin, the effective number of ancestors ranged from 17 (on-farm Romanov breed ) to 59 (Bleu du Maine breed). On the basis of the rate of inbreeding, the realized effective size was found to range from 65 (Romanov breed ex situ) to 231 (Bleu du Maine breed). The average kinship coefficients between rams from which semen doses are available in the National cryobank and the active ram and ewe populations were also computed. Results found in each breed were analyzed by taking into consideration the breeds’ demographic evolution, their management practices, and the use of cryopreservation as a way to preserve genetic variability. It appeared quite clear that, in populations where AI with frozen semen is seldom used, factors that mainly impact the genetic variability are the female/male ratio, which should be as low as possible, and the number of female offspring left by male, which should be as balanced as possible. Finally, our work showed that all populations under study have fairly good genetic variability in comparison with other species, despite their scarce numbers.

Effect of dietary organic and inorganic micromineral source and level on sow body, liver, colostrum, mature milk, and progeny mineral compositions over six parities

Peters, J. C., Mahan, D. C., Wiseman, T. G., Fastinger, N. D. — Fri, 09 Oct 2009 07:34:58 PDT

A sow study evaluated the effects of 2 dietary micromineral sources (organic or inorganic) and 3 dietary mineral levels [NRC, industry (IND), and IND + Ca:P] with selected sows killed at parities 1, 2, 4, and 6. Threes sows per treatment group were killed at weaning (total = 68) and their body and liver, 72 colostrum and milk samples (17 d), 69 full-term stillborn pigs and their livers, and 32 pigs at weaning were analyzed for minerals. The sow's tissue and milk samples were analyzed as a 2 x 3 x 4 factorial in a completely randomized design (CRD) with 3 replicates per treatment. Full-term stillborn pig mineral compositions were determined at parities 1, 3, and 5 and evaluated as a 2 x 3 x 3 factorial in a CRD with 3 replicates per treatment. Weanling pigs from parity 6 sows were analyzed as a 2 x 3 factorial in a CRD. Sow and pig mineral compositions are reported on an equivalent empty BW and kg liver weight basis. The results indicated that sow body macromineral contents were not affected by dietary micromineral source or level or when the diets contained added Ca and P. Sow body Se increased when dietary organic microminerals increased from the NRC to the IND level, resulting in a source x level interaction (P < 0.01), but there was no increase in those sows fed inorganic microminerals. There were increases in Cu (P < 0.05) and Se as levels increased from NRC to the IND, and increases (P < 0.05) in Cu and Zn when the IND + Ca:P diet was fed compared to feeding the IND diet. Increases (P < 0.01) in sow liver Cu, Se, and Zn occurred as microminerals increased from the NRC to the IND level. As parity advanced, there were cubic increases (P < 0.01) in sow body Cu, Fe, and Se, but a quadratic increase in Zn (P < 0.05). There was no clear effect of sow dietary treatments on full-term stillborn pig or liver micromineral contents, except Se (P < 0.01). There was a greater pig body Se content when sows were fed organic microminerals at the greater level, resulting in a source x level interaction (P < 0.01). Colostrum minerals were generally not affected by diet variables, except Se. Colostrum Se was greater when sows were fed the organic micromineral source than the inorganic source at the greater level, resulting in a source x level interaction (P < 0.05). Milk Cu (P < 0.01) and Zn (P < 0.01) increased as dietary level increased. Milk Se increased when organic Se was fed (P < 0.05) and the micromineral level increased (P < 0.01). Weaned pig body Fe (P < 0.01) and Se (P < 0.01) were greater when organic microminerals were fed to the sow, while Mn (P < 0.01) and Zn (P < 0.05) increased when the IND level was fed. These results indicate that the dietary micromineral source and level had a minimal effect on sow body and liver mineral contents or in colostrum and pigs at birth, except Se which was greater when the organic form was fed.

Redox regulation of cysteine-dependent enzymes

Guttmann, R. P. — Fri, 09 Oct 2009 07:34:56 PDT

It is well-established that maintenance of the intracellular redox (i.e., reduction-oxidation) state is critical for cell survival and that prolonged or abnormal perturbations towards oxidation result in cell dysfunction. This is exemplified by the widespread observation of oxidative stress in many pathological conditions, as well as the positive effects of anti-oxidants in treating certain conditions or extending life-span itself. In addition to the effects of oxidation on the lipid bi-layer and modification of DNA in the nucleus, proteins are also modulated by redox state. One of the primary targets of oxidation within a protein is the amino acid cysteine, whose thiol side chain is highly sensitive to all types of oxidizing agents. While this sensitivity is used to prevent oxidation within the cell as potent defense mechanisms, such as glutathione, the use of cysteine in the active site of enzymes leaves them open to oxidant-mediated damage. Whether the damage is due to a pathological condition or to post-mortem mediated loss of redox homeostasis, cysteine-dependent enzymes are targets of all forms of reactive oxygen, nitrogen and sulfur species. A greater understanding the redox-mediated control of cysteine-dependent enzymes opens the door to the selective use of anti-oxidants to prevent or reverse the cellular damage their inhibition causes.

Applying technology with newer feed ingredients in feedlot diets: Do the old paradigms apply?

DiLorenzo, N., Galyean, M. L. — Fri, 09 Oct 2009 07:34:55 PDT

Use of coproducts like corn and sorghum distillers grain (DG) and corn gluten feed (CGF) in beef cattle finishing diets has increased significantly in recent years, but research to evaluate the efficacy of traditional feeding practices and feed additives when coproducts are fed has not kept pace. Grain processing methods that increase starch availability seem equally effective in traditional diets and diets with wet CGF; however, in wet DG diets, some studies have shown decreased efficacy of grain processing, whereas others have shown no evidence of an interaction. Limited data are available on the physical and nutritional value of the fiber in wet DG and CGF; however, CGF at levels ≥ 25% of the dietary DM seems to have some degree of ‘roughage value,’ whereas fiber in wet DG seems to have less potential to replace traditional roughage sources. There is little evidence that efficacy of ionophores and antibiotics is changed with diets based on wet CGF or that they interact with addition of wet DG to finishing diets. In vitro data from our laboratory suggest no loss of monensin efficacy in substrates with 15% (DM basis) corn DG in terms of changes in VFA and gas production. Moreover, efficacy of ionophores was not affected in our data by diet substrates with increasing concentrations of S, and in vitro H₂S production in substrates containing wet DG seems predictable from substrate S concentrations. Nonetheless, limited in vivo data indicate lower ruminal acetate:propionate ratios with diets high in wet DG, which may minimize the potential for ionophores to alter propionate. Likewise, in vivo results indicate that feeding wet DG may decrease ruminal pH; thus, to maximize DMI and minimize digestive upsets, optimal concentrations of roughage need to be evaluated in diets containing wet DG. Research is needed on other potential technology interactions with coproducts of biofuel production like glycerol and condensed distillers solubles. The effects of yeast products and live microbial cultures in diets with coproduct feeds have generally not been determined. Because of the high fiber concentration in CGF and DG, effects of exogenous enzyme preparations on ruminal fermentation and fiber digestion of diets containing these coproducts should be evaluated.

Impacts of maternal nutrition on conceptus growth and offspring performance: Implications for beef cattle production

Funston, R. N., Larson, D. M., Vonnahme, K. A. — Fri, 09 Oct 2009 07:34:55 PDT

Developmental programming is the concept that a maternal stimulus or insult at a critical period in fetal development has long-term effects on the offspring. Historically, considerable efforts have been made to understand how nutrition influences health and productivity during the postnatal period. Whereas maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition affects the offspring’s health and productivity. Conceptus growth is sensitive to direct and indirect effects of maternal dietary intake. Even from the earliest stages of embryonic life when nutrient requirements for conceptus growth are negligible, alterations in tissue composition can occur, influencing future growth of the compromised organ system. Not only is neonatal health compromised, but subsequent health may be programmed because offspring from undernourished dams have exhibited poor growth and productivity and developed significant diseases later in life. While the literature is now evolving with increasing evidence of how maternal nutrient restriction impairs several prenatal physiological variables, few studies have evaluated post-natal growth and development in livestock species, and fewer have evaluated it in beef cattle. In addition, very few studies have evaluated restriction of specific components of the diet during pregnancy (such as protein) on offspring growth and performance. This review focuses on how maternal nutrition impacts conceptus growth and postnatal responses in beef cattle.

Applications of population data analysis in on-farm dairy trials

Engstrom, M., Sanchez, W., Stone, W., St-Pierre, N. R. — Fri, 09 Oct 2009 07:34:54 PDT

With appropriate management controls and statistical designs, on-farm trials are an increasingly valuable research tool. On-farm trials can speed up technology adoption, particularly with those studies requiring large numbers of animals. Useful designs include longitudinal (‘pen vs. pen’) trials, in which pen comprises the experimental unit, and crossover or switchback designs, in which treatments are imposed on a schedule over one or more experimental groups. A ‘paired-herd’ design has been used, in which herds are the experimental units in a crossover trial. Others have published similar studies including a multi-site crossover design that utilized 35 dairy farms to compare milk responses to a protein source, using individual cow records to evaluate differences in milk production. Recently statistical process control (SPC) techniques have been used to evaluate management changes using repeated measures on the farm. Although a drawback to SPC may be the lack of traditional statistics to test differences (i.e., the lack of a control group), standard run rules are used to demonstrate with statistical certainty that a process or variable has changed, or to characterize a seasonal change. With SPC, the inference is limited to the herd or group of animals being monitored. Meta-analysis techniques are powerful tools used to combine results from many similar trials where the response of interest is either small (i.e., continuous variables) or of low frequency (i.e., discrete variables). Meta-analysis can be used to segment a database so as to validate and compare trial methods or to investigate publication bias. Additional design concerns for reproduction studies include the need for adequate numbers of observations and planning for the lag time between an experimental treatment and response measurement (e.g., confirmation of pregnancy).

An animal breeding approach to the estimation of genetic and environmental trends from field populations

Garrick, D. J. — Fri, 09 Oct 2009 07:34:54 PDT

Observed or phenotypic trends in animal performance can be readily quantified from information collected from research or field populations. Phenotypic performance is determined by the collective impact of: systematic effects that vary by trait but may include: herd, year, sex, and age; additive genetic effects; and a remainder that is referred to as the lack-of-fit or unexplained residual. It is of interest to partition observed performance into these respective components to determine the extent to which genetic and(or) environmental trends are responsible for any observed phenotypic trends. An animal breeding approach to separate these components from field data involves the use of a linear model that includes fixed effects for systematic terms and random effects for genetic and residual contributions. The fitted random effects are predicted using a shrinkage estimator known as best linear unbiased prediction (BLUP) that relies only on a translation invariant subset of the field data that does not involve the unknown fixed effects. Fixed effects can then be estimated by adjusting observations for estimates of the random effects. Reliable estimation of trends using this approach requires that relevant fixed effects are recorded, cohorts representing different fixed effects classes are genetically related or connected, and that any records used as the basis for selection in the population are included in the dataset.

Influence of the inclusion of cooked cereals and pea starch in diets based on soy or pea protein concentrate on nutrient digestibility and performance of young pigs

Parera, N., Lazaro, R. P., Serrano, M. P., Valencia, D. G., Mateos, G. G. — Fri, 09 Oct 2009 07:34:53 PDT

An experiment was conducted to compare different dietary vegetable sources of starch and protein on the coefficient of apparent total tract digestibility (CATTD) of energy and nutrients and performance of piglets from 29 to 60 d of age. The experiment was completely randomized with 6 treatments arranged factorially with 3 sources of starch (cooked-flaked corn, cooked-flaked rice, and pea starch) and 2 sources of protein [soy protein concentrate (SPC) and pea protein concentrate (PPC)]. The pea starch and the PPC used were obtained by dehulling and grinding pea seeds to a mean particle size of 30 µm. Each treatment was replicated 6 times (6 pigs per pen). For the entire experiment, piglets fed cooked rice had higher ADG than piglets fed pea starch with piglets fed cooked corn being intermediate (471, 403, and 430 g/d, respectively; P < 0.05). Protein source did not have any effect on piglet performance. The CATTD of DM, OM, and GE were greater (P < 0.05) for diets based on cooked rice than diets based on cooked corn with diets based on pea starch being intermediate. Crude protein digestibility was not affected by source of starch but was greater for the diets based on SPC than for diets based on PPC (0.836 vs. 0.821; P < 0.01). Protein source did not affect the digestibility of any of the other dietary components. It is concluded that cooked rice is an energy source of choice in diets for young pigs. The inclusion of PPC in the diet reduced protein digestibility but had no effects on energy digestibility or piglet performance. Therefore, the finely ground starch and protein fractions of peas can be used in substitution of cooked corn or soy protein concentrate, respectively, in diets for young pigs.

Assessment of DGAT1 and LEP gene polymorphisms in three Nelore (Bos indicus) lines selected for growth and their relationship with growth and carcass traits

Fri, 09 Oct 2009 07:34:53 PDT

The aim of this study was to analyze LEP and DGAT1 gene polymorphisms in 3 Nelore lines selected for growth and to evaluate their effects on growth and carcass traits. Traits analyzed were birth, weaning, and yearling weight, rump height, Longissimus muscle area, backfat thickness, and rump fat thickness obtained by ultrasound. Two SNPs in the LEP gene [LEP 1620(A/G) and LEP 305(T/C)] and the K232A mutation in the DGAT1 gene were analyzed. The sample consisted of 357 Nelore heifers from 2 lines selected for yearling weight and a control line, established in 1980, at the Estação Experimental de Zootecnia de Sertãozinho. Three genotypes were obtained for each marker. Differences in allele frequencies among the 3 lines were only observed for the DGAT1 K232A polymorphism, with the frequency of the A allele being higher in the control line than in the selected lines. The DGAT1 K2132A mutation was associated only with rump height, while LEP 1620(A/G) was associated with weaning weight and LEP 305(T/C) with birth weight and backfat thickness. However, more studies, with larger data sets, are necessary before these makers can be used for marker assisted selection.

Metabolic acidosis in sheep alters expression of renal and skeletal muscle amino acid enzymes and transporters

Fri, 09 Oct 2009 07:34:52 PDT

To determine the effect of metabolic acidosis on expression of L-glutamine (Gln), L-glutamate (Glu), and L-aspartate (Asp) metabolizing enzymes and transporters, the relative content of mRNA, protein, or mRNA and protein, of 6 enzymes and 5 transporters was determined by real-time RT-PCR and immunoblot analyses in homogenates of kidney, skeletal muscle, and liver of growing lambs fed a common diet supplemented with either canola meal (Control; n = 5) or HCl-treated canola meal (Acidosis; n = 5). Acidosis sheep had a 790% greater (P = 0.050) expression of renal Na⁺-coupled neutral amino acid transporter 3 mRNA and a decreased expression of renal glutamine synthetase mRNA (56% reduction, P = 0.037) and protein (43% reduction, P = 0.015) than Control sheep. No change in renal cytosolic phosphoenolpyruvate carboxykinase (protein and mRNA), glutaminase (mRNA), or Glu dehydrogenase (protein) was found. In skeletal muscle, Acidosis sheep had 101% more (P = 0.026) aspartate transaminase protein than did Control sheep, whereas no change in the content of three Na⁺-coupled neutral amino acid transporters (mRNA), or two high-affinity Glu transporter proteins was found. In liver, no change in the content of any assessed enzyme or transporter was found. Collectively, these findings suggest that tissue-level responses of sheep to metabolic acidosis are different than for nonruminants. More specifically, these results indicate the potential capacity for metabolism of Asp and Glu by skeletal muscle, and Gln absorption by kidneys, but no change in hepatic expression of Gln metabolism, elaborates previous metabolic studies by revealing molecular-level responses to metabolic acidosis in sheep. The reader is cautioned that the metabolic acidosis model employed in this study differs from the high plasma lactate-induced metabolic acidosis commonly observed in ruminants fed a highly fermentable grain diet.

Genomic prediction of simulated multi-breed and purebred performance using observed 50k SNP genotypes

Kizilkaya, K., Fernando, R. L., Garrick, D. J. — Fri, 09 Oct 2009 07:34:52 PDT

Genomic prediction involves characterization of chromosome fragments in a training population to predict merit. Confidence in the predictions relies on their evaluation in a validation population. Many commercial animals are multibreed (MB) or crossbred but seedstock populations tend to be purebred (PB). Training in MB allows selection of PB for crossbred performance. Training in PB to predict MB performance quantifies the potential for across-breed genomic prediction. Efficiency of genomic selection was evaluated for a trait with heritability 0.5 simulated using actual SNP genotypes. The PB population had 1,086 Angus animals and the MB population had 924 individuals from 8 sire breeds. Phenotypic values were simulated for scenarios including 50, 100, 250, or 500 additive QTL randomly selected from 50k SNP panels. Panels containing various numbers of SNP, including or excluding the QTL were used in the analysis. A Bayesian model averaging method was used to simultaneously estimate the effects of all markers on the panels in MB (or PB) training populations. Estimated effects were utilized to predict genomic merit of animals in PB (or MB) validation populations. Correlations between predicted and simulated genomic merit in the validation population was used to reflect predictive ability. Panels that included QTL were able to account for 50% or more of the within-breed genetic variance when the trait was influenced by 50 QTL. The predictive power eroded as the number of QTL increased. Panels that comprised the QTL and no other markers were able to account for 50% or more genetic variance even with 500 QTL. Panels that included genomic markers as well as QTL had less predictive power as the number of markers on the panel was increased. Panels that excluded the QTL and relied on markers in linkage disequilibrium (LD) to predict QTL effects performed more poorly than marker panels with QTL. Real life situations with 50k panels that excluded the QTL could account for no more than 20% genetic variation for 50 QTL and less than 10% for 500 QTL. The difference between panels that included and excluded QTL indicates that the predictive ability of existing panels is limited by their LD. Training in PB to predict MB tended to be more predictive than training in MB to predict PB due to higher average levels of LD in PB than in MB populations. Improved across breed prediction of genomic merit will require panels with more than 50k markers.

Effects of ractopamine-HCl are not confined to mammalian tissue: Evidence for direct effects of ractopamine-HCl supplementation on fermentation by ruminal microorganisms

Walker, C. E., Drouillard, J. S. — Fri, 09 Oct 2009 07:34:52 PDT

Four experiments were conducted to investigate the effects of ractopamine-HCl (RAC) on ruminal fermentation and proteolysis. In Exp. 1, in vitro gas and VFA production were measured in flasks incubated with 0, 0.226, 2.26, 22.6, and 226.0 mg RAC/L buffered ruminal fluid. Ractopamine-HCl had a quadratic effect on in vitro gas production (P < 0.05; 177, 181, 185, 190, and 170 mL for 0, 0.226, 2.26, 22.6, and 226.0 mg, respectively). Total VFA production was not significantly changed with RAC (P > 0.50). In Exp. 2, IVDMD was measured with tubes incubated with 0, 0.226, 2.26, or 22.6 mg RAC/L buffered ruminal fluid with 4 substrate combinations: corn, corn plus soybean meal, corn plus urea, and corn plus soybean meal plus urea. Dry matter disappearance was measured after 2, 4, 6, 8, or 12 h of fermentation. There was an interaction between RAC and substrate (P < 0.01), with more degradable forms of nitrogen eliciting greater IVDMD from RAC. Significant main effects also were detected for RAC, substrate, and hour (P < 0.001). In Exp. 3, AA and ammonia (NH₃) were measured in tubes treated with 0 or 2.26 mg RAC/L buffered ruminal fluid. Tubes were incubated for 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 210, or 240 min. There were decreases in NH₃and AA concentrations with RAC (P < 0.001). Experiment 4 utilized 16 ruminally fistulated Holstein steers in a 2 x 2 x 2 factorial experiment. Factors consisted of grain processing method (steam-flaked or dry-rolled corn; SFC or DRC); level of dried distillers grain (DG) with solubles (0 or 25% DG, dry basis); and level of RAC (0 or 200 mg/d). Ruminal NH₃ concentrations were lower when RAC was fed in combination with DRC but not when fed in conjunction with SFC (Grain processing x RAC, P < 0.01). Addition of RAC, SFC, and DG all resulted in lower ruminal NH₃ concentrations (P < 0.01). Amino acid concentrations were decreased when RAC was added to diets with DG but were unchanged in diets without added DG (DG x RAC, P < 0.05). Changes in ruminal NH₃ and AA concentration with RAC supplementation are dependent on grain processing and the addition of DG to finishing diets. Results from these studies suggest that RAC affects fermentation by ruminal microflora. Effects of the interactions between RAC and protein source, grain processing, and DG on proteolysis could have important implications when formulating diets for cattle supplemented with RAC.

Technical Note: An R package for fitting generalized linear mixed models in animal breeding

Vazquez, A. I., Bates, D. M., Rosa, G. J. M., Gianola, D., Weigel, K. A. — Fri, 09 Oct 2009 07:34:51 PDT

Mixed models have been used extensively in quantitative genetics for the study of continuous and discrete traits. A standard quantitative genetic model poses that the effects of levels of some random factor (e.g., sire) are correlated accordingly with their relationships. For this reason, routines for mixed models available in standard packages cannot be used for genetic analysis. The pedigreemm package of R was developed as an extension of the lme4 package, and allows fitting mixed models with correlated random effects for Gaussian, binary and count responses. Following Harville and Callanan (1989), a correlation between levels of the grouping factor (e.g., sire) is induced by post-multiplying the incidence matrix of the levels of this random factor by the Cholesky factor of the corresponding (co)variance matrix e.g., the numerator relationship matrix between sires. Estimation methods available in pedigreemm include approximations to maximum likelihood and restricted maximum likelihood. This note describes the classes of models that can be fitted using pedigreemm and presents examples that illustrate its use.

Proteins involved in iron metabolism in beef cattle are affected by copper deficiency in combination with high dietary manganese, but not by copper deficiency alone

Fri, 09 Oct 2009 07:34:51 PDT

A 493-d study was conducted to determine the impact of a severe, long-term Cu deficiency on Fe metabolism in beef cattle. Twenty-one Angus calves were born to cows receiving one of the following treatments: 1) adequate Cu (+Cu), 2) Cu deficient (-Cu), and 3) Cu deficient plus high Mn (-Cu+Mn). Copper deficiency was induced through the addition of 2 mg Mo/kg DM. Following weaning, calves remained on the same treatment as their dam through growing (basal diet analyzed 7 mg Cu/kg DM) and finishing (analyzed 4 mg Cu/kg DM) phases. Plasma Fe concentrations were positively correlated (P < 0.01; r = 0.49) with plasma Cu concentrations. Liver Fe concentrations were greater (P = 0.05) in -Cu vs. +Cu calves and further increased (P = 0.07) in -Cu+Mn vs. -Cu calves. There was a negative relationship (P < 0.01; r = -0.31) between liver Cu and Fe concentrations. This relationship is likely explained by lower (P < 0.01) plasma ceruloplasmin activity in -Cu. vs. +Cu calves. As determined by real-time RT-PCR, relative expression of hepatic hepcidin was significantly down-regulated (> 1.5 fold) in –Cu compared with +Cu calves (P < 0.03) and expression of hepatic ferroportin tended (P = 0.09) to be down-regulated in -Cu vs. +Cu. In the duodenum, ferritin was suggestively up-regulated in -Cu. vs. +Cu calves (P < 0.06). No significant change due to Cu-deficiency was detected at the transcriptional level for either isoform of divalent metal transporter 1 (DMT1 mRNA with or without an iron responsive element; dmt1IRE and dmt1-nonIRE) in liver or intestine. Duodenal expression of hephaestin and ferroportin protein was not affected by dietary treatment (P > 0.2). However, duodenal expression of DMT1 protein was lower (P = 0.04) in -Cu+Mn steers vs. -Cu steers. In summary, Cu deficiency alone did affect hepatic gene expression of hepcidin and ferroportin, but did not affect duodenal expression of proteins important in Fe metabolism. However, the addition of 500 mg Mn/kg DM to a diet low in Cu reduced duodenal expression of the Fe import protein DMT1.

Postweaning growth and carcass traits in crossbred cattle from Hereford, Angus, Brangus, Beefmaster, Bonsmara, and Romosinuano maternal grandsires

Casas, E., Thallman, R. M., Kuehn, L. A., Cundiff, L. V. — Fri, 09 Oct 2009 07:34:50 PDT

The objective of this study was to characterize breeds representing diverse biological types for postweaning growth and carcass composition traits in terminal crossbred cattle. Postweaning growth and carcass traits were analyzed on 464 steers and 439 heifers obtained by mating F₁ cows to Charolais and MARC III (1/4 Hereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) sires. The F₁ cows were obtained from mating Angus and MARC III dams to Hereford, Angus, Beefmaster, Brangus, Bonsmara, and Romosinuano sires. Traits evaluated were postweaning ADG, slaughter weight, HCW, dressing percentage, percentage of carcasses classified as USDA Choice, LM area, marbling score, USDA yield grade, fat thickness, retail product yield (percentage), and retail product weight. Maternal grandsire breed was significant (P < 0.05) for all traits. Animals with Angus grandsires grew faster, had the heaviest carcasses, with the highest percentage of carcasses classified as USDA Choice and the highest marbling scores, when compared to other grandsire breeds. Animals with Romosinuano and Bonsmara inheritance grew slower, had the lightest weights at slaughter, the lightest carcass weights, the lowest percentage of carcasses classified as USDA Choice, and the least amount of marbling and fat thickness. Animals with inheritance from these two breeds had a more desirable yield grade with the highest retail product yield. Maternal granddam breed was significant for marbling score, USDA yield grade, fat thickness and retail product yield. Sex class was significant (P < 0.05) for all traits except for retail product yield. Steers grew faster, were heavier, had heavier carcasses, and were leaner than heifers. Heifers had a higher dressing percentage, a higher percentage of carcasses classified as USDA Choice, a greater LM area, and a lower yield grade when compared to steers. Sire and grandsire breed effects can be optimized by selection and use of appropriate crossbreeding systems.

Effect of divergence in residual feed intake on feeding behavior, blood metabolic variables, and body composition traits in growing beef heifers

Kelly, A. K., McGee, M., Crews, D. H., Fahey, A. G., Wylie, A.R., Kenny, D. A. — Fri, 09 Oct 2009 07:34:49 PDT

This study examined the relationship of feed efficiency and performance with feeding behavior, blood metabolic variables, and various body composition measurements in growing beef heifers. Individual DMI and growth were measured in yearling Limousin x Holstein-Friesian heifers (n = 86; initial BW = 191.8 (SD = 37) kg) fed a TMR diet comprising 70:30 concentrate:corn silage on a DM basis (ME 2.65 Mcal/kg DM; DM 580 g/kg) for 82 d. Meal duration (min/d) and meal frequency (events/d) were calculated for each animal on a daily basis using the Insentec computerized feeding system. Physical measurements as well as ultrasonic fat and muscle depths were recorded on 3 equally spaced occasions during the experimental period. Blood samples were collected by jugular venipuncture on 4 equally spaced occasions and analyzed for plasma concentrations of IGF-I, insulin, leptin, and various metabolites. Phenotypic residual feed intake (RFI) was calculated for all animals as the residuals from a multiple regression model regressing DMI on ADG and mid-test BW^0.75. Overall, ADG, DMI, feed:gain (F:G), and RFI were 1.51 (SD = 0.13), 6.74 (SD = 0.99), 4.48 (SD = 0.65) and 0.00 (SD = 0.48) kg/d, respectively. Residual feed intake was positively correlated with DMI (r = 0.47) and F:G (r = 0.46) but not with ADG or MBW. Moderate positive correlations ranging from 0.27 to 0.67 were estimated between ultrasonic measures of lumbar fat and accretion over the test period and DMI, FCR, and RFI. The inclusion of gain in lumbar fat to the base RFI model increased R² (0.77 vs. 0.80) of the variation in DMI not explained by MBW and ADG. The Pearson rank correlation between RFI and carcass-adjusted RFI (RFI_c) was high (r = 0.93). From the plasma analytes measured, NEFA (r = -0.23) and BHB (r = 0.39) concentration were correlated (P < 0.05) with RFI. Plasma glucose (r = -0.20), leptin (r = 0.48), glucose:insulin (r = -0.23), NEFA (r = -0.36) and BHB (r = 0.25) were associated (P < 0.05) with F:G. However, systemic IGF-I and insulin were unrelated (P < 0.05) to any measure of feed efficiency. The feeding behavior traits of eating rate, feeding events, and non-feeding events were positively correlated (P < 0.05) with RFI and RFI_c.This multifactorial study provides new information on some of the biological processes responsible for variation in feed efficiency in beef cattle.

The effect of variation at the retinoic acid receptor-related orphan receptor C gene on intramuscular fat percent and marbling score in Australian cattle

Barendse, W., Bunch, R. J., Harrison, B. E. — Fri, 09 Oct 2009 07:34:48 PDT

Variation at the retinoic acid receptor-related orphan receptor C (RORC) gene was previously associated to marbling score in a large sample of Australian taurine feedlot cattle of Angus and Shorthorn breeds. The T allele at the single nucleotide polymorphism (SNP) RORC:g.3290T>G increased marbling score in Angus and Shorthorn cattle. We genotyped this SNP in an independent sample of 2,741 Australian cattle of Angus, Brahman, and Hereford breeds, and tested the association of this SNP with marbling score in all animals and with intramuscular fat (IMF) measurements in 2,104 animals. We found an allele frequency of the G allele of p_G = 0.57 in Angus, p_G = 0.09 in Hereford and p_G = 0.64 in Brahman. The regression of marbling score against number of copies of the G allele was significant (P = 0.033) in the combined sample after accounting for ancestry, breed and the contemporary group structure of the data. All breeds had the same favorable homozygote; the regression on alleles showed a trend in Angus and Brahman cattle (P < 0.1) but not in Hereford cattle (P = 0.912). The regression of IMF against number of copies of the G allele was significant (P = 0.018), after accounting for ancestry, breed and contemporary group structure. All breeds had the same favorable homozygote and the regression on alleles was significant (P = 0.024) in Angus breed. In all breeds tested in this study, the T allele increased both marbling score and IMF. This polymorphism explained 0.3% of the phenotypic variance for IMF in this sample.

The small intestinal epithelia of beef steers differentially express sugar transporter mRNA in response to abomasal vs ruminal infusion of starch hydrolysate

Fri, 09 Oct 2009 07:34:48 PDT

In mammals, the absorption of monosaccharides from small intestinal lumen involves at least 3 sugar transporters (ST): SGLT1 (gene SLC5A1) transports glucose and galactose, while GLUT5 (gene SLC2A5) transports fructose, across the apical membrane of entrocytes. In contrast, GLUT2 (gene SLC2A2) transports all of these sugars across both basolateral and apical membranes. To compare the distribution patterns and sensitivity to nutritional regulation of these 3 ST mRNA in beef cattle small intestinal tissue, 18 ruminally and abomasally catheterized Angus steers (BW 260 kg) were assigned to either water (control), ruminal cornstarch (partially hydrolyzed by -amylase; SH), or abomasal SH infusion treatments (n = 6) and fed an alfalfa-cube based diet at 1.3x NE_m requirement. The SH infusions amounted to 20% of ME intake. After 14- or 16-d of infusion, steers were killed, duodenal, jejunal, and ileal epithelia harvested, and total RNA extracted. The relative amount of ST mRNA in epithelia was determined using real-time RT-PCR quantification methods. Basal expression of GLUT2 and SGLT1 mRNA was greater (P < 0.09) by jejunal than by duodenal or ileal epithelia, whereas basal content of GLUT5 mRNA was greater (P ≤ 0.02) by jejunal and duodenal than by ileal epithelia. The content of GLUT5 mRNA in small intestinal epithelia was not affected (P ≥ 0.16) by either SH infusion treatment. In contrast, both GLUT2 and SGLT1 mRNA content in the ileal epithelium was increased (P ≤ 0.05) by 6.5- and 1.3-fold, respectively, after abomasal SH infusion. Duodenal SGLT1 mRNA content also was increased (P = 0.07) by 64% after ruminal SH infusion. These results demonstrate that the ileum of beef cattle small intestine adapts to an increased luminal supply of glucose by increasing SGLT1 and GLUT2 mRNA content, whereas increased ruminal SH supply results in duodenal upregulation of SGLT1 mRNA content. These adaptive responses of GLUT2 and SGLT1 mRNA to abomasal or ruminal SH infusion suggest that beef cattle can adapt to increase their carbohydrate assimilation through small intestinal epithelia, assuming that altered ST mRNA contents reflect the altered transport functional capacities.

Consequences of long-term inbreeding accumulation on preweaning traits in a closed nucleus Angus herd

Carrillo, J. A., Siewerdt, F. — Fri, 09 Oct 2009 07:34:47 PDT

The effect of individual and dam (maternal) inbreeding was quantified for preweaning traits in an Angus nucleus herd that has been closed to outside breeding for 70 years. The effectiveness of five models (linear, quadratic, exponential, Michaelis-Menten, and Rumford-Newton) was evaluated for describing the effect of inbreeding on growth traits, hock length (HL), and scrotal circumference (SC). Pedigree information and production records were retrieved for 10,938 animals and analyzed in an animal model that included the fixed effects of year of birth, age of the dam, gender, age at weaning (for traits measured at weaning). Average individual and maternal inbreeding in the herd were 0.068 and 0.066 respectively, for all animals; in the last calf crop these values were 0.120 for the calves and 0.121 for their dams. Inbreeding depression was observed for weight at birth (WB), weaning weight (WW), body weight adjusted to 205 d of age (W205), ADG, HL and SC. The effect of maternal inbreeding was smaller than for individual inbreeding for WB, WW, W205 and ADG. Nonlinear prediction was done more effectively by the exponential and Michaelis-Menten models. Quadratic polynomials were an inadequate descriptor of inbreeding effects. Genetic gain from selection at an intensity equivalent to 0.25 can be nullified by an inbreeding accumulation of 0.187 (WB), 0.056 (WW), 0.068 (W205), 0.065 (ADG), or 0.092 (SC). Inbreeding accumulation of 0.018 is required to nullify genetics gain for HL; this particular prediction is valid for non-inbred cows due to an observed interaction between individual and maternal inbreeding. At current inbreeding accumulation levels in this herd, seven generations of inbreeding accumulation will be necessary to nullify the genetic progress from one generation of selection in growth traits.

Estimation of breed and heterosis effects for growth and carcass traits in cattle using published crossbreeding studies

Williams, J. L., Aguilar, I., Rekaya, R., Bertrand, J. K. — Fri, 09 Oct 2009 07:34:58 PDT

Current genetic evaluations are performed separately for each breed. Multiple breed genetic evaluations, however, assume a common base among breeds enabling producers to compare cattle of different breed makeup. Breed and heterosis effects are needed in a multi-breed evaluation because databases maintained by breed associations include few crossbred animals which may not be enough to accurately estimate these effects. The objective of this study was to infer breed effects (BE), maternal effects (ME), direct heterosis effects, and maternal heterosis effects for growth and carcass traits using least square means estimates from crossbreeding studies published in the literature from 1976 to 1996. The dataset was formed by recording each least square mean along with the breed composition, maternal breed composition, and direct and maternal heterozygosity. Each trait was analyzed using a single trait fixed effect model which included study as a fixed effect and breed composition and heterozygosity as covariates. Breed solutions for each trait were expressed relative to the Angus breed. Direct BE for weaning weight ranged from -7.0 ± 0.67 kg (British Dairy) to 29.3 ± 0.74 kg (Simmental) and ME ranged from -11.7 ± 0.24 kg (Hereford) to 31.1 ± 2.22 kg (Gelbvieh). Direct BE for birth weight ranged from -0.5 ± 0.14 kg (British Dairy) to 10.1 ± 0.46 kg (Continental Beef) and ME ranged from -7.2 ± 0.13 kg (Brahman) to 6.0 ± 1.07 kg (Continental Beef). Direct BE ranged from -17.9 ± 1.64 kg (Brahman) to 21.6 ± 1.95 kg (Charolais), from -6.5 ± 1.29 kg (Brahman) to 55.8 ± 1.47 kg (Continental Beef), from -8.1 ± 0.48 cm²(Shorthorn) to 21.0 ± 0.48 cm² (Continental Beef), and from -1.1 ± 0.02 cm (Continental Beef) to 0 ± 0.00 cm (Angus) for post weaning gain, carcass weight, rib eye area, and fat thickness, respectively. The use of literature estimates to predict direct and maternal breed and heterosis effects may supplement their direct prediction in a multi-breed evaluation.

Evaluation of dried distiller's grains and roughage source in steam-flaked corn finishing diets

Fri, 09 Oct 2009 07:34:57 PDT

Two studies were conducted to evaluate effects of dried distiller’s grains with solubles (DDGS) and alfalfa hay or corn silage on feedlot performance, carcass characteristics, ruminal fermentation, and diet digestibility in cattle fed steam-flaked corn (SFC) diets. In trial 1, crossbred heifers (n = 358; BW = 353 ± 13 kg) were used in a finishing trial to evaluate interactions between corn-DDGS and roughage source [alfalfa hay (AH) or corn silage (CS)] in terms of impact on feedlot performance and carcass characteristics. Experimental diets (DM basis) consisted of SFC and 11% CS without DDGS (SFC-CS), SFC and 11% CS with 25% DDGS (DDGS-CS), SFC and 6% AH without DDGS (SFC-AH), and SFC with 25% DDGS and 6% AH (DDGS-AH). Heifers were fed for ad libitum intake once daily for 97 d. Results indicated no interaction between DDGS and roughage source with respect to animal performance. Feeding DDGS did not affect ADG (P = 0.19), DMI (P = 0.14), or feed conversion (P = 0.67). Heifers fed CS had greater DMI than those fed AH (P = 0.05), but ADG (P = 0.56) and G:F (P = 0.63) were not different. There were no differences among treatments with respect to HCW, dressing percentage, subcutaneous fat thickness, quality grades, or yield grades (P > 0.20). Cattle fed CS tended (P = 0.10) to have higher marbling scores than those fed AH. There was an interaction (P = 0.02) between roughage and DDGS with respect to incidence of liver abscess. The highest incidence was observed in cattle fed diets without DDGS when CS was fed, and the lowest was observed in cattle fed diets without DDGS when AH was used. In the second trial, ruminal fermentation characteristics and diet digestibility were examined in 12 cannulated Holstein steers fed similar diets to those fed in the finishing trial. Ruminal pH for all treatments was below 5.8 for 14 h after feeding. Steers fed 25% DDGS had lower (P = 0.02) acetate:propionate ratios but higher (P = 0.02) ruminal lactate concentrations than cattle fed 0% DDGS. Feeding 25% DDGS decreased (P < 0.01) ruminal ammonia concentrations, and digestion of DM and OM were less (P < 0.01) compared to diets without DDGS. The decrease in digestibility was largely attributable to decreases in digestion of CP (P = 0.03) and NDF (P < 0.01). Feeding strategies aimed at increasing ruminal pH and ruminally available protein may improve digestion of DDGS in steam-flaked corn-based finishing diets.

Estimates of genetic parameters among scale activity scores, growth, and fatness in pigs

Holl, J. W., Rohrer, G. A., Brown-Brandl, T. M. — Fri, 09 Oct 2009 07:34:50 PDT

Genetic parameters for scale activity score were estimated from generations five, six, and seven of a randomly selected, composite population composed of Duroc, Large White, and two sources of Landrace (n = 2,186). At approximately 156 d of age, pigs were weighed (WT) and ultrasound backfat measurements (BF1, BF2, and BF3) were done. While pigs were in the scale, a scale activity score (AS) was assigned, which ranged from 1 (calm) to 5 (highly excited); where 58.1%, 28.5%, 8.9%, 4.0% and 0.5% were scored as 1, 2, 3, 4, and 5, respectively. Statistical model effects were year-week of measurement, sex, covariates of age for AS and WT or weight for BF1, BF2, and BF3, and an animal direct genetic effect. A five-trait linear mixed model was employed. Estimated heritabilities were 0.23, 0.54, 0.56, 0.52, and 0.48 for AS, WT, BF1, BF2, and BF3, respectively. Estimated genetic correlations between AS and WT, AS and BF1, AS and BF2, and AS and BF3 were -0.38, -0.11, -0.12, and -0.16 respectively. Results indicated AS had a heritable genetic component and was genetically correlated with performance traits. Estimated genetic correlations between AS and backfat measurements adjusted to a common weight were negative as well as the genetic correlation of AS with WT. Therefore, selection for more docile animals would be expected to result in faster growing, fatter pigs.

Ileal microbiota of growing pigs fed different dietary calcium phosphate levels and phytase content and subjected to ileal pectin infusion

Fri, 09 Oct 2009 07:34:46 PDT

Two experiments with growing pigs were conducted to determine the effects of dietary P and Ca level, phytase supplementation and ileal pectin infusion on changes in bacterial populations in the ileum and ileal and fecal fermentation patterns. Growing pigs (BW 30.1 ± 1.3 kg) were fitted with simple T-cannulas at the distal ileum and were fed a low-P corn-soybean meal control diet (3 g P/kg), or the control diet either supplemented with 15 g monocalcium phosphate (MCP)/kg (Exp. 1) or 1,000 FTU phytase/kg (Exp. 2). Daily infusion treatments consisted of 60 g pectin dissolved in 1.8 L demineralized water or 1.8 L demineralized water as control infusion, infused via the ileal cannula. In each experiment, 8 barrows were assigned to 4 dietary treatments according to a double incomplete 4 x 2 Latin square design. The dietary treatments in Exp. 1 were the control diet with water infusion; control diet with pectin infusion; MCP diet with water infusion or MCP diet with pectin infusion. In Exp. 2, the pigs received the same control treatments as in Exp. 1 and the phytase diet in combination with water or pectin infusion. Gene copy numbers of total bacteria, Lactobacillus spp., L. reuteri, L. amylovorus/L. sobrius, L. mucosae, Enterococcus spp., E. faecium, E. faecalis, bifidobacteria, Clostridium coccoides cluster, C. leptum cluster, Bacteroides-Prevotella-Porphyrmonas group and Enterobacteriaceae were determined by quantitative PCR in DNA extracts of ileal digesta. In Exp. 1, MCP addition reduced ileal gene copy numbers of Enterococcus spp. (P = 0.048), E. faecium (P = 0.015) and C. leptum cluster (P = 0.028); whereas, pectin infusion enhanced (P = 0.008) ileal d-lactate concentration. In Exp. 2, supplemental phytase led to greater ileal gene copy numbers of the C. coccoides (P = 0.041) and C. leptum cluster (P = 0.048), Bacteroides-Prevotella-Porphyrmonas group (P = 0.033), whereas it reduced (P = 0.027) fecal n-butyrate concentration. Pectin infusion reduced (P = 0.005) ileal gene copy number of the C. leptum cluster. In conclusion, ileal bacterial populations and fermentation patterns are susceptible to changes in the intestinal availability of Ca and P as well as to the supply of pectin as fermentable substrate. Higher intestinal Ca availability decreased the numbers of some gram-positive bacteria, while higher P availability in the small intestine due to phytase activity enhanced the growth of strictly anaerobic bacteria.

Genetic associations between carcass traits measured by real time ultrasound and scrotal circumference and growth traits in Nelore cattle

Fri, 09 Oct 2009 07:34:46 PDT

The aim of the present study was to evaluate the genetic correlations among real time ultrasound carcass, body weight (BW) and scrotal circumference (SC) traits in Nelore cattle. Carcass traits, measured by real time ultrasound of the live animal, were recorded from 2002 to 2004 on ten farms across six Brazilian states on 2,590 males and females ranging in age from 450 to 599 d. Ultrasound records of longissimus muscle area (LMA) and backfat thickness (BF) were obtained from cross-sectional images between the 12th and 13th ribs, and rump fat thickness (RF) was measured between the hook and pin bones over the junction between gluteus medius and biceps femoris muscles. Also, BW (n = 22,778) and SC (n = 5,695) were recorded on animals born between 1998 and 2003. The BW traits were 120, 210, 365, 450 and 550-d standardized weights (W120, W210, W365, W450 and W550), plus weight (WS) and hip height (HH) on the ultrasound scanning date. The SC traits were 365, 450 and 550-d standardized SC (SC365, SC450 and SC550). For the BW and SC traits, the database used was from the Nelore Breeding Program - Nelore Brazil. The genetic parameters were estimated with multivariate animal models and REML. Estimated genetic correlations between LMA and other traits were 0.06 (BF), -0.04 (RF), 0.05 (HH), 0.58 (WS), 0.53 (W120), 0.62 (W210), 0.67 (W365), 0.64 (both W450 and W550), 0.28 (SC365), 0.24 (SC450) and 0.00 (SC550). Estimated genetic correlations between BF and with other traits were 0.74 (RF), -0.32 (HH), 0.19 (WS), -0.03 (W120), -0.10 (W210), 0.04 (W365), 0.01 (W450), 0.06 (W550), 0.17 (both SC365 and SC450) and -0.19 (SC550). Estimated genetic correlations between RF and other traits were -0.41 (HH), -0.09 (WS), -0.13 (W120), -0.09 (W210), -0.01 (W365), 0.02 (W450), 0.03 (W550), 0.05 (SC365), 0.11 (SC450) and -0.18 (SC550). These estimates indicate that selection for carcass traits measured by real time ultrasound should not cause antagonism in the genetic improvement of SC and BW traits. Also, selection to increase HH might decrease subcutaneous fat as correlated response. Therefore, to obtain animals suited to specific tropical production systems, carcass, BW and SC traits should be considered in selection programs.

Effects of sex and short-term magnesium supplementation on stress responses and LM quality characteristics of crossbred cattle

Fri, 25 Sep 2009 09:33:04 PDT

Calf-fed heifers (n = 72) and steers (n = 72) were supplemented with 4 levels (0%, 0.25%, 0.50%, and 0.75%) of dietary magnesium (Mg) as Mg oxide (MgO) during the final 14 d of finishing and commingled 1 d before slaughter (inducing stress due to mixing of unfamiliar cattle) to examine the effects of sex class and Mg supplementation on stress responses and LM quality characteristics. Heifers and steers exhibited markedly different stress responses. Heifers were more excitable than steers during pre-slaughter handling events and exhibited a short-term physiological stress response that involved acute sympatho-adrenal activation and resulted in increased meat toughness, without a concomitant increase in muscle pH. Steers, on the other hand, exhibited greater physical activity, associated with agonistic behavior, during the mixing period and, therefore, produced carcasses with lower (P = 0.008) LM glycogen levels and higher (P = 0.042) 48-h LM pH values, compared with heifers. Steers also produced tougher (P = 0.008) LM steaks than did heifers. Within the range of pH values observed in this study (5.3 to 6.1), positive, linear relationships between 48-h LM pH and mean LM shear force (P < 0.05) were observed in both heifers (r = 0.25) and steers (r = 0.37). Effects of pH on LM shear force (P < 0.05), which were most pronounced at 3 and 7 d postmortem, diminished during postmortem aging and were no longer evident (P > 0.05) once LM samples had been aged for 21 d. Results suggested that toughness of LM steaks from beef carcasses with final LM pH values greater than 5.65 could be problematic, unless LM cuts are aged for approximately 18 d or longer. Supplementation with dietary Mg increased (P = 0.011) serum Mg concentration, but had no effect (P > 0.05) on any of the physiological stress indicators or LM quality characteristics measured in this study. There was no evidence to support the premise that Mg supplementation of cattle lessens the effects of pre-slaughter stress on beef quality characteristics.

Tissue expression of angiopoietin-like protein 4 in cattle

Mamedova, L. K., Robbins, K., Johnson, B. J., Bradford, B. J. — Fri, 25 Sep 2009 09:33:03 PDT

Angiopoietin-like protein 4 (ANGPTL4; also known as fasting-induced adipose factor) is a plasma protein that stimulates oxidation of fatty acids and inhibits fat accumulation. The gastrointestinal (GI) tract appears to play an important role in regulating plasma ANGPTL4 concentration in some situations and may be influenced by microbes within the GI tract. Our aim was to determine which tissues express ANGPTL4 in the bovine. Rumen, omasum, abomasum, duodenum, jejunum, ileum, colon, pancreas, liver, and subcutaneous adipose tissue samples were collected postmortem from 2 steers. Abundance of ANGPTL4 mRNA was quantified by quantitative real-time PCR (qPCR), and was most abundant in liver and adipose tissue (P < 0.05). We also detected ANGPTL4 mRNA throughout the GI tract, although its abundance was approximately 10% of that found in liver and adipose tissue. Western blot analysis revealed that ANGPTL4 protein was most abundant in liver and adipose tissue (P < 0.05), but omasal, abomasal, and illeal samples contained at least 60% as much ANGPTL4 protein as the liver and adipose tissue samples, and the protein was detected in all tissues. Finally, cross sections of the liver, pancreas, and rumen wall were used for indirect immunofluorescent detection of ANGPTL4. Despite the low abundance of ANGPTL4 measured with qPCR and Western blot in ruminal tissue, immunofluorescence demonstrated that expression of ANGPTL4 in ruminal epithelial cells was equivalent to or greater than that in liver hepatocytes. These findings indicate that, like in other species studied, liver and adipose tissue are key sources of ANGPTL4 in cattle. However, the protein was also highly abundant in ruminal epithelium, making it possible that commensal microbes may influence ANGPTL4 synthesis and secretion in the ruminant GI tract.

Effect of dietary omega-3 fatty acid source on plasma and red blood cell membrane composition and immune function in yearling horses

Vineyard, K. R., Warren, L. K., Kivipelto, J. — Fri, 25 Sep 2009 09:33:03 PDT

To determine the effect of different sources of dietary omega-3 (n-3) fatty acids (FA) on plasma and red blood cell (RBC) FA composition and immune response, 18 Quarter Horse yearlings were randomly and equally assigned to one of 3 treatments: encapsulated fish oil (FISH, n = 6), milled flaxseed (FLAX, n = 6), or no supplementation (CON, n = 6). Fish oil contained 15 g eicosapentaenoic acid (C20:5n-3) and 12.5 g docosahexaenoic acid (C22:6n-3) and FLAX contained 61 g -linolenic acid (C18:3n-3) per 100 g FA. Horses had free access to bahiagrass pasture during the active growing season and were individually fed a grain mix concentrate at 1.5% BW/d. Fish oil and FLAX were mixed into the concentrate in amounts to provide 6 g total n-3/100 kg BW. Horses were fed their respective treatments for 70 d. Blood samples were obtained to determine plasma and RBC FA composition and for isolation of peripheral blood mononuclear cells. Peripheral blood mononuclear cells were stimulated with Concanavalin A and phytohemagglutinin (PHA) to determine lymphocyte proliferation and challenged with lipopolysaccharide to determine PGE₂ production. In vivo inflammatory response was assessed on d 70 by measuring skin thickness and area of swelling in response to intradermal injection of PHA. Treatment did not affect BW gain, which averaged 0.6 ± 0.03 kg/d. Horses fed FISH had a higher (P < 0.05) proportion of eicosapentaenoic acid, docosahexaenoic acid, and sum n-3 in plasma and RBC compared to FLAX and CON. In addition, plasma arachidonic acid was higher (P < 0.05) and plasma linoleic and -linolenic acids were lower (P < 0.05) in FISH compared to FLAX and CON. Dietary treatment did not affect lymphocyte proliferation or PGE₂ production. Across treatments, peak increase in skin thickness was observed 4 to 8 h after PHA injection. At 4 h post-injection, FISH and FLAX had a greater increase in skin thickness than CON (P < 0.05) and FISH had a larger area of swelling than CON (P < 0.05). Skin thickness remained greater (P < 0.05) in FLAX than CON 6 h after injection. Although fed to supply a similar level of n-3 FA, FISH had a greater impact on plasma and RBC n-3 FA content than FLAX. However, supplementation with both FISH and FLAX resulted in a more pronounced early inflammatory response to PHA injection as compared to non-supplemented horses.

Suckling behavior in captive plains zebra (Equus burchellii): sex differences in foal behavior

Pluhacek, J., Bartosova, J., Bartos, L. — Fri, 25 Sep 2009 09:33:02 PDT

Based on parent offspring conflict theory and on the assumption that all mothers were in good condition due to captivity, we predicted that the proportion of suckling attempts rejected and terminated by the mother would be higher for female foals than male foals. We presumed that an increasing rate of suckling terminated or rejected by a mother should indicate a decreasing effort of the mother to invest in her offspring. We observed foals of captive plains zebra at the Dvur Králové Zoo. We found that the probability of successful suckling tended to increase with increasing age of female foals, but decreased with increasing age of male foals. The proportion of suckling bouts terminated by the mother decreased with increasing age of female foals, but not male foals. Our results indicate that conflict between mothers and female foals was lesser than that between mothers and male foals. The observed sex differences in termination and rejection of suckling bouts could be explained by the different behavior of the male and female foals, or by the selective maternal investment. Finally, we revealed no significant effect of herdmates on suckling behavior.

Intramuscular fat and fatty acid composition of longissimus muscle from divergent pure breeds of cattle

Fri, 25 Sep 2009 09:33:01 PDT

The objective of this study was to compare the fatty acid (FA) composition of the intramuscular (i.m.) fat of the longissimus muscle (LM) from three divergent breeds of cattle: Angus (AN, n = 9), Brahman (BR, n = 7), and Romosinuano (RM, n = 11). Cattle were blocked by breed and finished 129 d prior to harvest in one year and 159 d in the next year. Longissimus muscle samples were collected from each carcass between the 10^th and 13^th ribs, trimmed of external fat, frozen in liquid nitrogen, homogenized, and utilized for fat extraction using the modified Folch procedure. Extracted fat was analyzed for fatty acids using a GLC system with an HP-88 capillary column. Fatty acid composition was expressed using both a normalized percentage (%) and gravimetric calculation (mg/g of fresh muscle tissue), in relation to degree of saturation, which was determined using saturation index (SI, ratio of total SFA to total unsaturated fatty acids). Crude fat determination revealed that LM from AN purebred cattle had the highest amount of i.m. fat (7.08%, P = 0.001). While i.m. fat of LM from RM contained a lower percentage of total SFA (P = 0.002) as compared to only that of LM from AN, it had the highest percentage of total PUFA (P < 0.001 and P = 0.020). The percentage of total MUFA was similar among the three breeds (P = 0.675). The gravimetric calculation, a measure of actual FA concentration, showed significantly higher concentrations of SFA (26.67 mg/g) and MUFA (26.50 mg/g), and PUFA (2.37 mg/g) in LM from AN cattle, as compared to LM from BR and RM cattle (P < 0.001). Interestingly, BR purebreds had the lowest PUFA concentration (1.49 mg/g; P ≤ 0.001) in the LM, although their i.m. fat content was found to be similar to that of RM (P = 0.924). Regardless of breed, the MUFA proportion was always the highest (47.58%, P ≤ 0.005) while PUFA was the lowest contributor to FA composition (1.49 mg/g to 2.37 mg/g and 4.36% to 8.78%, P < 0.001). Beef LM fatty acid composition was characterized by palmitic and oleic acids being the most abundant fatty acids (P < 0.001). These results suggested a genetic variation in FA synthesis and deposition among breeds that influenced both marbling and its composition.

Effect of dietary cation-anion difference on measures of acid-base physiology and performance in beef cattle

Hersom, M. J., Hansen, G. R., Arthington, J. D. — Fri, 25 Sep 2009 09:33:01 PDT

Dietary constituents can affect cow acid-base physiology and uterine pH. Dietary cation-anion difference (DCAD) has been shown to affect cow acid-base physiology but the effect on uterine pH has not been demonstrated. The objective of this work was to determine if DCAD [(Na + K + 0.15Ca + 0.15Mg) - (Cl + 0.60S + 0.50P)] could affect cow DMI, acid-base physiology, and uterine pH and secondly, to determine if dietary supplements could alleviate any negative effects of DCAD on these variables. In Exp. 1, 21 cows were utilized to determine the effect of a negative DCAD (-0.9 mEq/100 g DM; Low-DCAD) or positive DCAD (+25.0 mEq/100 g DM; High-DCAD) diet on cow BW, DMI, and pH of blood, urine, and uterine flush fluid. In Exp. 2, 21 cows were randomly allotted to 1 of 3 treatments: Control (-3.1 mEq/100 g DM), Molasses (+2.9 mEq/100 g DM), or Molasses+buffer (+25.8 mEq/100 g DM) to determine if supplemental liquid molasses or liquid molasses with a buffer could alleviate the effects of a negative DCAD, forage-based diet. Cows were individually fed their respective diets for 42 d in both experiments. Cow BW, blood, urine, and uterine flush were collected on d 0, 21, and 42 during both experiments. Cow ADG was not different (P = 0.71) in Exp. 1 or Exp. 2 (P = 0.47). Hay DMI did not differ (P < 0.70) between High-DCAD and Low-DCAD cows prior to d 28, but was greater (P < 0.001) for High-DCAD cows after d 28 in Exp. 1. In Exp. 2, mean hay DMI did not differ (P = 0.39) among treatments. In Exp. 1, a treatment x day interaction (P < 0.05) was apparent for blood, pH, base excess, bicarbonate, pCO₂ and urine pH. Blood gas and pH measures peaked on d 21 for High-DCAD and declined from d 0 to 42 in Low-DCAD cows. High-DCAD cows had greater (P = 0.08) uterine flush pH compared to Low-DCAD cows. In contrast, during Exp. 2 there were no differences (P > 0.14) among treatments for blood, pH, base excess, pCO₂, or uterine flush pH. Urine pH exhibited a treatment x day interaction (P < 0.0001). On d 21 molasses supplemented cow urine pH was greater (P < 0.0001) than Control cows, whereas on d 42 Molasses+buffer had greater (P = 0.01) urine pH compared to Control and Molasses cows. Dietary cation-anion difference and the use of molasses-based supplements had minimal effect on forage-fed beef cow DMI. However, DCAD has the capacity to alter forage-fed beef cow acid-base physiology and potentially affect uterine physiology.

Evaluation of elevated dietary corn fiber from corn germ meal in growing female pigs

Weber, T. E., Trabue, S. L., Ziemer, C. J., Kerr, B. J. — Fri, 25 Sep 2009 09:33:00 PDT

To evaluate the effects of dietary hemicellulose from corn on growth and metabolic measures, female pigs (n = 48; initial BW 30.8 kg) were fed diets containing 0 to 38.6% solvent-extracted corn germ meal for 28 d. Increasing the hemicellulose level had no impact on ADG or ADFI, but resulted in a quadratic response (P < 0.03) on G:F. To investigate physiological changes that occur with increased dietary hemicellulose, blood, colon contents, and tissue samples from the liver and intestine were obtained from a subset (n = 16; 8 pigs/treatment) of pigs fed the lowest and highest hemicellulose levels. The abundance of phospho-AMP-activated protein kinase (AMPK) and the mitochondrial respiratory protein, cytochrome C oxidase II (COXII), were determined in liver, jejunum, ileum, and colon by western blotting. The mRNA expression levels of AMPK1, AMPK2, peroxisome proliferator activated receptor coactivator 1 (PGC1-), peroxisome proliferator activated receptor (PPAR2) and sirtuin 1 (Sirt1) were determined in liver and intestinal tissues. When compared to pigs fed the control diet, pigs fed the high hemicellulose diet had increased (P < 0.02) plasma triglycerides, but there was no difference in plasma cholesterol, glucose, or insulin. Absolute and relative liver weights were decreased (P < 0.03) in pigs consuming the high hemicellulose diet. The high-fiber diet led to a tendency (P < 0.12) for decreased liver triglyceride content. In pigs fed the high hemicellulose diet, ileal mucosal alkaline phosphatase activity was increased (P < 0.08) and sucrase activity tended (P < 0.12) to be increased. The high hemicellulose diet had no effect on phospho-AMPK, AMPK mRNA or colonic VFA, but in pigs consuming the high fiber diet there was a greater (P < 0.05) abundance of COXII in colon tissue. The expression of PGC1-, PPAR or Sirt1 mRNAs was not altered by dietary fiber in liver, jejunum, or ileum tissue. In colon tissue from pigs fed the high fiber diet there was an increase (P < 0.09) in Sirt1 mRNA and a trend (P < 0.12) toward increased of PGC1- mRNA. These data suggest that alterations in metabolism involved in adaptation to a diet high in hemicellulose are associated with increased colonic Sirt1 mRNA and COXII expression, indicating an increased propensity for oxidative metabolism by the intestine.

Manipulating grain processing method and roughage level to improve feed efficiency in feedlot cattle

Turgeon, O. A., Szasz, J. I., Koers, W. C., Davis, M. S., Vander Pol, K. J. — Fri, 25 Sep 2009 09:33:00 PDT

The effects of feeding finishing diets containing whole corn with no roughage on performance and carcass characteristics of feedlot steers were evaluated in 6 trials conducted at commercial research facilities (Bos Technica Research Services, Inc.; Salina, KS) in the Southern Plains of the United States. One hundred two feedlot pens containing 6,895 steers were represented. All trials were designed as randomized complete blocks with pen serving as the experimental unit. Steers were fed and managed similarly across all trials. Treatments consisted of a typical control finishing diet with various grain sources and processing methods that contained roughage and a finishing diet containing whole corn (8 to 23% of diet DM) but without added roughage. Final BW was greater (P < 0.1) for steers fed typical finishing diets than for steers fed whole corn diets without roughage in 5 of the 6 trials. Feeding finishing diets containing whole corn but without roughage resulted in decreased (P < 0.1) ADG and carcass ADG in 5 of the 6 trials. However, DMI also was lower (P < 0.1) for steers fed whole corn finishing diets without roughage in all trials such that feeding whole corn diets without roughage improved (P < 0.05) G:F (liveweight basis) in 2 of the 6 trials, and improved (P < 0.1) G:F based on carcass weight in 5 of the 6 trials. Dry matter intake as a percentage of BW daily across trials was well predicted from percentage of dietary NDF from roughage, being 1.906 + 0.0199 (± 0.0012) NDF (P < 0.05). Performance-based NE_g content of the diet was greater (P < 0.07) for steers fed whole corn diets without roughage. Differences in USDA yield and quality grades were inconsistent. Results indicate that feeding diets containing whole corn with no added roughage tends to decrease DMI and ADG in finishing steers but improves feed efficiency and performance-calculated dietary NE_g.

Additive effects of a steroidal implant and zilpaterol-HCl on feedlot performance, carcass characteristics, and skeletal muscle mRNA abundance in finishing steers

Fri, 25 Sep 2009 09:33:00 PDT

This experiment investigated the effects of zilpaterol-HCl (ZH) and the steroidal implant Revalor-S (RS; 120 mg trenbolone acetate and 24 mg estradiol-17β) on finishing steer performance and the mRNA concentration of β-adrenergic receptors (β-AR) types I and II, and types I, IIA, and IIX myosin heavy chain (MHC) isoforms. A total of 2,279 feedlot steers weighing 426 ± 6.4 kg were administered no implant or RS on d 0, and fed either 0 or 8.3 mg ZH/kg of diet DM during the last 30 d with a 3 d withdrawal. Treatments were randomly assigned to 24 pens (n = 6 pens/treatment). At harvest, semimembranosus muscle tissue was excised for RNA isolation from 4 carcasses per pen. No interactions were detected for any of the variables measured in the experiment. Administration of ZH during the last 30 d of the feeding period increased (P < 0.01) ADG, G:F, HCW, and LM area; decreased (P < 0.01) 12th rib fat depth and marbling; and improved (P < 0.01) yield grade. Treatment had no effect on β1-AR mRNA levels, but there was an increase (P = 0.01) in β₂-AR mRNA levels due to ZH inclusion. Myosin heavy chain-I (MHC-I) mRNA levels were unaffected by treatment. For MHC-IIA mRNA concentrations, administration of RS tended (P = 0.08) to increase mRNA levels, whereas ZH feeding the last 30 d tended (P = 0.08) to decrease mRNA levels for this isoform of myosin. Feeding ZH the last 30 d prior to harvest increased (P < 0.01) mRNA concentrations of MHC-IIX in semimembranosus muscle of steers. These data indicate the combined use of ZH and RS additively contributes to live and carcass gain in finishing feedlot steers and decreases marbling scores and USDA quality grades. LMA increased and fat thickness decreased. In addition, ZH feeding changes the mRNA levels of MHC isoforms to a faster, more glycolytic fiber type in bovine skeletal muscle. These changes in mRNA concentrations of MHC isoforms, due to ZH feeding, could be affecting skeletal muscle hypertrophy.

Control of the estrous cycle to improve fertility for fixed-time artificial insemination (TAI) in beef cattle: A review

Lamb, G. C., Dahlen, C. R., Larson, J. E., Marquezini, G., Stevenson, J. S. — Fri, 25 Sep 2009 09:32:59 PDT

Early estrus-synchronization protocols focused on regressing the corpus luteum with an injection of prostaglandin F₂ (PG) followed by detection of estrus or involved the use of exogenous progestins that prevent estrus from occurring. Later, protocols combining the use of PG and exogenous progestins were developed. Gonadotropin-releasing hormone was utilized to control follicular waves, synchronize ovulation or to luteinize large dominant follicles. Our research aimed to develop reliable protocols that: 1) relied solely on fixed-timed AI (TAI); 2) required a maximum of 3 animal handlings, and 3) were successful in estrous-cycling and noncycling females. In cows, insertion of an intravaginal progesterone insert during the 7-d interval between the initial GnRH and PG injections enhanced pregnancy rates by 9 to 10%. In a multi-location study, a TAI protocol yielded pregnancy rates similar to a protocol involving detection of estrus plus a fixed-time clean-up AI for females not detected in estrus (54 vs. 58%, respectively, for cows and 53 vs. 57%, respectively, for heifers). Initiation of estrous cycles in noncycling cows is likely the primary manner in which beef producers may improve fertility in response to estrus synchronization and TAI protocols. Treatment of noncycling females with progesterone and GnRH increases the percentage of cycling females and improves fertility to a TAI, but inducing cyclicity with hCG failed to enhance fertility in TAI protocols. Supplementing progesterone after TAI failed to increase pregnancy rates in beef cattle. In contrast, administration of hCG 7 d after TAI induced an accessory CL, increased progesterone, and tended to enhance pregnancy rates. Development of TAI protocols that reduce the hassle factors associated with ovulation synchronization and AI provide cattle producers efficient and effective tools for capturing selective genetic traits of economic consequences. Location variables, however, that may include differences in pasture and diet, breed composition, body condition, postpartum interval, climate, and geographic location, affect the success of TAI protocols.

Invited Review: Feeding behavior of goats

Goetsch, A. L., Gipson, T. A., Askar, A. R., Puchala, R. — Fri, 25 Sep 2009 09:32:59 PDT

Factors influencing feeding behavior of goats include grazing management practices, type of vegetation and season, breed and stage of production, group size, and properties of diets fed in confinement. Considerable information has been gathered from visual observation during daylight. However, there are now tools available to characterize feeding behavior of goats while grazing and in confinement throughout the day. Global positioning system collars can be used to assess horizontal and vertical distances traveled, up or down position of the head, and movement within pasture or rangeland areas. A commercially available leg activity monitor allows estimation of the number of steps and time spent standing, lying, and moving rapidly without grazing. However, these measurements do not directly determine grazing. Therefore, prediction equations based on visual observation must be developed. Classification tree analysis is a robust method in developing these equations because the decision tree can be pruned or expanded to provide the best fit. Another equipment system determines time spent eating, ruminating, and idle from pattern of jaw movement. In addition to use of n-alkanes as internal markers to estimate digestibility, their profile can provide an indication of botanical composition of the selected diet. Automated feeding systems for confined goats permit determinations such as number of feeder visits and meals, eating time, and rate and pattern of feed intake. Heart rate measured while goats are in normal production settings can be used to predict total energy expenditure through multiplication by energy expenditure per heart beat of individual animals. To partition the activity energy cost, an estimate of ME intake or measures of change in body energy status and milk energy yield are needed to determine other sources of heat to be subtracted from total energy expenditure. These methods create opportunity to gain a fuller understanding of factors influencing feeding behavior of goats and relationships with levels and efficiencies of production.

Contractile response of fescue-naive, bovine lateral saphenous veins to increasing concentrations of tall fescue alkaloids

Klotz, J. L., Kirch, B. H., Aiken, G. E., Bush, L. P., Strickland, J. R. — Fri, 25 Sep 2009 09:32:58 PDT

Various alkaloids found in endophyte-infected tall fescue have been shown to elicit different effects in the grazing animal. As part of an ongoing characterization of vascular response generated by different alkaloids, the objective this study was to examine the vasoconstrictive potentials of ergonovine (a simple lysergic acid derivative) and -ergocryptine, ergocristine, and ergocornine (all ergopeptine alkaloids) using bovine lateral saphenous veins (cranial branch) biopsied from fescue-naïve cattle. Segments (2 to 3 cm) of vein were surgically biopsied from healthy cross-bred yearling cattle (n = 18; 274 ±8 kg). Veins were trimmed of excess fat and connective tissue, sliced into 2 to 3 mm sections and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O₂/5% CO₂; pH = 7.4; 37°C). Tissue was allowed to equilibrate at 1 g of tension for 90 min prior to initiation of treatment additions. Increasing doses of each alkaloid (1x10^-10 to 1x10^-4 M) were administered every 15 min following buffer replacement. Data were normalized as a percent of contractile response induced by a reference dose of norepinephrine (1x10^-4 M). Exposure of vein segments to increasing concentrations of ergocryptine, ergocristine, and ergonovine did not result in a contractile response until 1x10^-7 M, and ergocornine was even less potent (P < 0.05). Ergonovine had a greater maximal contractile intensity than ergocristine and ergocryptine (P < 0.05), with the 1x10^-4 M responses of ergonovine, ergocristine, ergocryptine, and ergocornine reaching maximums of 68.5 ± 4.1, 45.5 ± 4.5, 42.9 ± 4.1%, and 57.2 ± 9.9% of the norepinephrine maximum, respectively. The contractile response to increasing concentrations of ergonovine vs. ergocryptine, ergocristine, and ergocornine were opposite from previous evaluations of ergoline (e.g. lysergic acid) and ergopeptine (e.g. ergovaline) alkaloids using this bioassay, where the ergopeptine generated the greater contractile intensity. These data indicate that ergopeptines structurally different only at a single position of the peptide moiety do not exhibit differing contractile responses when considering contractile intensity. This difference may alter the potency when considering ergocornine was less potent than ergocryptine or ergocristine. These alkaloids may need to be considered when evaluating causative agents vasoconstriction associated with tall fescue-induced toxicosis.

Effect of phytase on apparent total tract digestibility of phosphorus in corn-soybean meal diets fed to finishing pigs

Kerr, B. J., Weber, T. E., Miller, P. S., Southern, L. L. — Fri, 25 Sep 2009 09:32:58 PDT

Five experiments were conducted to investigate the ability of different phytase products to improve P digestibility in finishing pigs. A corn-soybean meal basal diet containing 0.50% Ca, 0.32% P, and 0.40% Cr₂O₃ was used to calculate apparent P and GE digestibility. Pigs were individually penned and fed their respective diet for ad libitum intake for 12 d prior to fecal sampling on d 13 and 14, and blood collection on d 14 for plasma P determination. Experiments 1 through 4 utilized gilts with an across-trial average initial and final BW of 84 and 97 kg, respectively. Pigs were fed Natuphos (Exp. 1), Optiphos (Exp. 2), Phyzyme (Exp. 3), or Ronozyme (Exp. 4) at 0, 200, 400, 600, 800, or 1,000 FTU/kg (FTU, 1 phytase unit is defined as the quantity of enzyme required to liberate 1 µmol of inorganic P per min, at pH 5.5, from an excess of 15 µmol/L sodium phytate at 37°C). Experiment 5 utilized barrows with an initial and final BW of 98 and 111 kg, respectively, and were fed diets containing 0, 500, or 1,000 FTU/kg of Natuphos, Optiphos, Phyzyme, or Ronozyme. Pigs fed Natuphos (Exp. 1) and Optiphos (Exp. 2) exhibited a linear and quadratic (P < 0.01) improvement in P digestibility with increasing levels of dietary phytase, whereas pigs fed Phyzyme (Exp. 3) and Ronozyme (Exp. 4) exhibited a linear (P < 0.01) improvement in apparent P digestibility with increasing levels of dietary phytase. In Exp. 5, the improvement in apparent P digestibility with increasing levels of dietary phytase was linear (P < 0.01) for Natuphos, Phyzyme, and Ronozyme, but linear and quadratic (P < 0.01) for Optiphos. Using regression analysis, inorganic P release at 500 FTU/kg was predicted to be 0.070, 0.099, 0.038, and 0.030% for Natuphos, Optiphos, Phyzyme, and Ronozyme, respectively. These estimates are comparable to pigs in Exp. 5 where the estimated inorganic P release at 500 FTU/kg was 0.102, 0.039, and 0.028% for Optiphos, Phyzyme, and Ronozyme, respectively, but not for the 0.034% value determined for Natuphos. The effect of dietary phytase on GE digestibility was inconsistent with a linear (P < 0.01) improvement in GE digestibility noted for Optiphos (Exp. 2 and 5) and Ronozyme (Exp. 4), but quadratic (P < 0.01) for Natuphos. There was no effect of dietary phytase on plasma inorganic P. Data presented show clear improvements in P digestibility with the estimated level of inorganic P release being dependent upon phytase source and level.

Type of accommodation during gestation affects growth performance and reproductive characteristics of gilt offspring

Estienne, M. J., Harper, A. F. — Fri, 25 Sep 2009 09:32:58 PDT

The objective was to determine effects of the type of gestation accommodation to which dams were exposed on growth performance and age at puberty in gilt offspring. Yorkshire x Landrace gilts (n = 81; 26.9 + 0.8 kg) were placed in pens of 3 gilts each. Each pen contained gilts farrowed exclusively by gilts exposed to 1 of 3 gestation accommodations: I. individual crates throughout gestation, II. group pens throughout gestation, or III. crates for 30 d post-mating and then group pens for the remainder of gestation (n = 9 pens/group). Performance during the 5-wk nursery period was similar among groups. The grow-finish period ended at a BW of 108.9 + 0.8 kg and ADG (0.98 + 0.02 kg) was not affected (P = 0.14) by treatment. However, pig BW was affected by accommodation type x time (P = 0.04), with gilts farrowed by females housed in crates throughout gestation being heaviest during the last 4 wk. There was no effect of treatment on ADFI (2.61 + 0.07 kg; P = 0.54); however, G:F was enhanced (P < 0.05) in gilts farrowed by females housed in crates throughout (0.385 + 0.005) or for the first 30 d of gestation and then groups (0.382 + 0.005) compared with gilts from females kept in groups throughout gestation (0.367 + 0.005). Gilts from females gestated in crates throughout gestation tended (P < 0.09) to have less backfat (10.9 + 0.5 mm) than gilts from females gestated in groups (12.5 + 0.5 mm). After grow-finish, gilts were checked for estrus once daily. Mean age at puberty (171.9 + 4.4 d) did not differ among groups (P = 0.61); however, fewer gilts farrowed by females gestated in crates throughout gestation (P = 0.03) reached puberty by 165 d of age (13%) compared with the other 2 groups (44%). Although specific mechanisms need to be determined, we suggest that the type of gestation accommodation in which gilts are kept may affect production performance of gilt offspring, possibly by fetal programming.

Dietary supplementation with different forms of flax in late-gestation and lactation: Effects on sow and litter performances, endocrinology and immune response

Farmer, C., Giguere, A., Lessard, M. — Fri, 25 Sep 2009 09:32:57 PDT

The impact of feeding flax as seed, meal or oil to late-pregnant and lactating sows on hormone concentrations, immune responses and sow and litter performances was studied. Sixty sows were fed 1 of 4 diets from 68 d of gestation until 21 d of lactation. Diets were: standard , CTL (n = 15); 10% flaxseed supplementation, FS (n = 16); 6.5% flaxseed meal supplementation, FSM (n = 14); and 3.5% flaxseed oil supplementation, FSO (n = 15). On d 88 and 101 of gestation, sows were immunized against ovalbumin (OVA). Jugular blood samples were obtained on d 62, 88 and 110 of gestation and on d 2 and 21 of lactation to measure concentrations of estradiol, prolactin, and progesterone as well as antibody (Ab) against OVA (anti-OVA), lymphocyte proliferation, and lymphocyte production of interferon- (IFN-). Milk samples were obtained on d 3 and 20 of lactation. One piglet per litter was slaughtered on d 1 for compositional analyses and a jugular blood sample was obtained for anti-OVA analyses. Remaining piglets were weighed on d 2, 7, 14, 21 (weaning), 28, and 56. Circulating hormone concentrations in sows were not affected by treatment overall (P > 0.1). On d 20 of lactation, milk from FS, FSM, and FSO sows had more protein than that from CTL sows (P < 0.01). The FSM piglets weighed more on d 56 (P < 0.05) than FS and FSO piglets. Carcasses of 1-d-old FSM piglets also had greater glycogen (P < 0.001) and DM (P = 0.05) contents than FS and FSO piglets, but organ weights and circulating concentrations of glucose and IGF-I did not differ (P > 0.1). In CTL sows, IFN- production decreased between d 101 of gestation and d 2 of lactation; whereas, in FS sows, it increased (P < 0.01). Anti-OVA for the whole experimental period was greater in FS than in FSO sows (P < 0.05). Concentrations of anti-OVA in milk on d 3 of lactation and lymphocyte proliferative responses were not affected by treatments (P > 0.1). Serum concentrations of anti-OVA in 2 d-old piglets that gained weight during the first 24 h after birth, were greater (P < 0.01) in FS, FSM and FSO litters than in CTL litters and percent mortality on d 2 and 21 postpartum was lower (P < 0.05) for FS, FSM and FSO litters compared with CTL. Therefore, feeding flax to sows may have beneficial effects on immune resistance of piglets and feeding FSM improved postweaning growth of piglets.

Fermented soybean meal as a vegetable protein source for nursery pigs: I. Effects on growth performance of nursery pigs

Kim, S. W., van Heugten, E., Ji, F., Lee, C. H., Mateo, R. D. — Fri, 25 Sep 2009 09:32:57 PDT

Four experiments were conducted using 671 nursery pigs to evaluate fermented soybean meal (FSBM) as a new vegetable protein source for nursery pigs. In Exp. 1, 192 pigs weaned at 19.2 ± 0.3 d of age were fed 3 diets (8 pens per treatment) for 2 wk: control (without FSBM) and 2 diets with FSBM at 3 and 6% replacing soybean meal (SBM) followed by a common diet for the following 2 wk. In Exp. 2, 160 pigs weaned at 21.6 ± 0.2 d of age were fed 4 diets (5 pens per treatment) for 2 wk: control (without FSBM but with 25% dried skim milk, DSM) and 3 diets with FSBM at 3, 6, and 9% by replacing DSM based on CP. Concentrations of CP, Lys, Met, Thr, and Trp were kept consistent among diets in Exp. 1 and 2. In Exp. 3, 144 pigs weaned at 22.1 ± 0.2 d of age were fed 3 diets (6 pens per treatment) for 2 wk: control (without FSBM but with 40% DSM) and 2 diets with FSBM at 5 and 10% by replacing DSM based on CP. Concentrations of CP, Lys, Met, Thr, Trp, and lactose were kept consistent among diets. In Exp. 4, 175 pigs weaned at 20.7 ± 0.4 d of age were fed 5 diets (5 pens per treatment) for 3 wk: basal [15.5% CP without plasma protein (PP) and FSBM], 2 diets (18.4% CP with 3.7% PP or 4.9% FSBM), and 2 diets (21.2% CP with 7.3% PP or 9.8% FSBM). Concentrations of Lys, Met, Thr, and Trp were kept consistent among diets with the same CP concentrations. Pigs had access to feed and water ad libitum and their BW and FI were measured weekly for all experiments. Use of FSBM up to 6% replacing SBM improved (P < 0.05) gain:feed and diarrhea score of nursery pigs (Exp. 1). Use of FSBM up to 9% replacing DSM reduced (P < 0.05) ADG and gain:feed (Exp. 2). When lactose concentrations were equal, FSBM could replace up to 10% DSM without adverse effects on ADG and gain:feed (Exp. 3). Relative bioavailability of protein in FSBM to PP was 99.1% (Exp. 4). Collectively, FSBM can serve as an alternative protein source for nursery pigs at 3 to 7 wk of age possibly replacing the use of DSM and PP, but excluding first week postweaning for PP, when balancing for AA and lactose.

Reproductive performance and bone status markers of gilts and lactating sows supplemented with two different forms of vitamin D

Lauridsen, C., Halekoh, U., Larsen, T., Jensen, S. K. — Fri, 25 Sep 2009 09:32:57 PDT

In swine nutrition, little is known about the requirements of vitamin D in reproductive processes and bone health. Vitamin D recommendation of sows during gestation and lactation is not consequently based on scientific reports. The current study was undertaken to obtain information on the dose-response pattern of two vitamin D sources, the commonly used cholecalciferol, called vitamin D₃, and a newly developed Hy•D product (25-hydroxycholecalciferol). In experiment 1, 160 gilts were randomly assigned from the first estrus until d 28 of gestation to dietary treatments containing 4 concentrations of one of the 2 different vitamin D sources [200, 800, 1,400, and 2,000 IU•kg^-1 from cholecalciferol or corresponding levels of 5, 20, 35 and 50 µg•kg^-1 feed from 25(OH)D₃ (Hy•D)]. In a concurrent experiment, the same 8 dietary treatments were provided to 160 multiparous sows from the first day of mating until weaning. The plasma concentration of 25(OH)D₃ was influenced by a dose and form interaction (P < 0.001), and furthermore by lactation state in the sows. Irrespective of dietary dose and form of vitamin D for the sows, very little vitamin D was transferred to the progeny. Reproductive performance was not influenced by dietary vitamin D treatments, except for a lower number of still born piglets (P = 0.03, SE = 0.40) with the high doses of vitamin D (1,400 and 2,000 IU vitamin D, giving 1.17 and 1.13 still born piglets per litter, respectively) compared with the low doses of vitamin D (200 and 800 IU vitamin D, giving 1.98 and 1.99 still born piglets per litter, respectively). In the gilt trial, the ultimate strength of the bones (P = 0.01) and their content of ash (P = 0.02) were higher when D₃ was supplemented in doses larger than 800 IU compared to the same level of Hy•D supplementation. In the sow experiment, lactation day (P < 0.001) rather than dietary vitamin D influenced the concentration of osteocalcin and calcium, and the activities of total alkaline phosphatase, and bone alkaline phosphatase in plasma. Age of the suckling piglets affected their plasma bone health markers. In conclusion, above 200 IU, Hy•D was more bioavailable than the vitamin D₃, and could as such be considered as an equivalent or even more advantageous source of vitamin D.A dietary level of around 1,400 IU vitamin D was concluded to be recommendable for reproducing swine. Irrespective dietary dose and form of vitamin D for the sows, very little vitamin D was transferred to the progeny.

Effect of dietary supplementation with glutamine and a combination of glutamine-arginine on intestinal health in 25-d-old weaned rabbits

Chamorro, S., de Blas, C., Grant, G., Badiola, I., Menoyo, D., Carabano, R. — Fri, 25 Sep 2009 09:32:56 PDT

The effect of dietary supplementation with 1% L-glutamine (Gln) and a combination of 1% L-glutamine (Gln) and 0.5% L-arginine (Arg) on intestinal health was examined in weaned rabbits. A basal diet was formulated to meet nutrient recommendations. Another 2 diets were formulated by adding 1% (as-fed basis) Gln, or a mixture of 1% (as-fed basis) Gln + 0.5% (as-fed basis) Arg (Gln-Arg) to the basal diet. In Exp. 1 a total of 357 rabbits were blocked by litter and assigned at random to the experimental diet to determine mortality (119 per diet) and growth performance (35 per diet; from weaning at 25- to 56-d-of age). Rabbits fed the experimental diets for a 2-wk period and thereafter received a commercial diet. Rabbits weaned at 25 d (blocked by litter and assigned at random to diets) were slaughtered at 35 d and used to determine apparent ileal digestibility (AID) of DM, CP and AA (Exp. 2, a total of 60 rabbits), intestinal morphology, N-aminopeptidase and myeloperoxidase intestinal activity, the expression of peroxisome proliferator-activated receptor gamma (PPAR) at ileum and kidney, serum immunoglobulin in healthy and sick rabbits (Exp. 3, a total of 24 rabbits), and ileal and cecal microbial composition by PCR-RFLP (Exp. 4, a total of 45 rabbits). Dietary treatment did not affect ADG, ADFI or G:F, during the entire fattening period. Supplementation with Gln reduced mortality both during the first 2 wk and the whole fattening period from 18.5 to 8.4% (P = 0.023) and from 31.9 to 20.2% (P = 0.039) respectively; whereas, no effect was detected for Arg supplementation. Among all the variables studied, the reduction on mortality due to Gln was related to a lower intestinal colonization (Eimeria lesions) and changes on microbial ecosystem in the ileum and cecum, reducing the frequency of detection of Clostridium spp. (from 86.7 to 33.3%, P = 0.003) at ileum, and Helicobacter spp. at ileum (from 86.7 to 46.7%, P = 0.003) and at cecum (from 86.7 to 46.7, P = 0.028); whereas, no effect was detected for Arg supplementation. In conclusion, 1% L-Gln supplementation to post-weaned rabbit diets decreased fattening mortality and modified the intestinal microbiota (although no consistent effects were observed on either mucosal histology or inflammatory and systemic immune response). Diets containing a combination of 1% Gln and 0.5% Arg were of little additional benefit.

Results from six generations of selection for intramuscular fat in Duroc swine using real-time ultrasound. II. Genetic parameters and trends

Schwab, C. R., Baas, T. J., Stalder, K. J. — Fri, 25 Sep 2009 09:32:56 PDT

Design of breeding programs requires knowledge of variance components that exist for traits included in specific breeding goals and the genetic relationships that exist among traits of economic importance. A study was conducted to evaluate direct and correlated genetic responses to selection for intramuscular fat (IMF) and to estimate genetic parameters for economically important traits in Duroc swine. Forty gilts were purchased from U.S. breeders and randomly mated for 2 generations to boars available in regional boar studs to develop a base population of 56 litters. Littermate pairs of gilts from this population were randomly assigned to either a select line (SL) or control line (CL) and mated to the same boar to establish genetic ties between lines. In the SL, the top 10 boars and 75 gilts were selected based on IMF EBV obtained from a bivariate animal model that included IMF evaluated on the carcass and IMF predicted via ultrasound. One boar from each sire family and 50 to 60 gilts representing all sire families were randomly selected to maintain the CL. Carcass and ultrasound IMF were both moderately heritable (0.31 and 0.38, respectively). Moderate to high genetic relationships were estimated among carcass backfat and meat quality measures of IMF, Instron tenderness, and objective loin muscle color. Based on estimates obtained in this study, more desirable genetic merit for pH is associated with greater genetic value for loin color, tenderness, and sensory characteristics. Intramuscular fat measures obtained on the carcass and predicted using ultrasound technology were highly correlated (r_g = 0.86 from a 12-trait analysis; r_g = 0.90 from a 5-trait analysis). Estimated genetic relationships among either IMF measure and other traits evaluated were generally consistent. Intramuscular fat measures were also genetically associated with Instron tenderness and flavor score in a desirable direction. Direct genetic response in IMF measures observed in the SL corresponded to a significant decrease in EBV for carcass loin muscle area (-0.90 cm² per generation) and an increase in carcass backfat EBV (0.98 mm per generation). Selection for IMF has led to more desirable EBV for objective tenderness and has had an adverse effect on additive genetic merit for objective loin color.

Genetic diversity and population structure of American Red Angus cattle

Marquez, G. C., Speidel, S. E., Enns, R. M., Garrick, D. J. — Fri, 25 Sep 2009 09:32:56 PDT

The objective of this study was to characterize the population structure and genetic diversity of registered American Red Angus cattle. Inbreeding and average relationship coefficients, effective population size, effective number of founders, and effective number of herds supplying grandparents to the population were calculated from the recorded pedigree. Inbreeding in 1960 was 10.7% and decreased until 1974 at a rate of 0.2% per yr, whereas in 1975 inbreeding was 3.2% and increased until 2005 at a rate of 0.02% per yr. The numerator relationship coefficients of the 10 individual paternal grandsires (PGS; sires of sires), paternal granddams (PGD; dams of sires), maternal grandsires (MGS; sires of dams), and maternal granddams (MGD; dams of dams) that had the greatest number of registered grandprogeny, with all other registered animals increased with their birth year, from 1960 on. Average numerator relationships of these with all other PGS, PGD, MGS, MGD, bulls, and sires were higher for paternal (PGS, PGD) than maternal (MGS, MGD) pathways. The effective population size was 445, with 649 effective founders. The effective number of herds supplying PGS, PGD, MGS, and MGD was 435, 369, 453, and 459, respectively. Inbreeding is at a low level and the effective population size is high. The effective number of founders and effective number of herds supplying grandparents is low in relation to the total number of animals and herds, indicating the disproportionate influence of a few founders and herds on the genetics of the breed. The calculated parameters indicate satisfactory genetic diversity in American Red Angus cattle.

Determining the effect of lysine:calorie ratio on growth performance of 10 to 20 kilogram nursery pigs of two different genotypes

Fri, 25 Sep 2009 09:32:55 PDT

Four experiments were conducted to determine the effects of standardized ileal digestible (SID) Lys:calorie (Lys:Mcal) ratio on growth performance of 10- to 20-kg pigs of 2 different genotypes. Experiment 1 (360 pigs, average BW = 10.2 kg; Source 1) and Exp. 2 (351 pigs; average BW = 9.3 kg; Source 2), were both organized as a combination of 2 simultaneous experiments with the first set of diets consisting of 5 treatments with increasing SID Lys and the second set of diets consisting of 5 treatments with increasing energy density (Exp. 1: 9.9, 10.7, 11.5, 12.2, and 13.0 g/kg Lys and 2.95, 3.09, 3.24, 3.38, and 3.52 Mcal of ME/kg, respectively; Exp. 2: 11.1, 11.9, 12.6, 13.4, and 14.2 g/kg and 2.95, 3.10, 3.25, 3.40, and 3.55 kcal of ME/kg, respectively). In Exp. 1, increasing dietary SID Lys increased (linear, P < 0.01) ADG and G:F, and increasing dietary ME increased (quadratic, P < 0.05) G:F. In Exp. 1 the optimal Lys:Mcal ratio was estimated to be at least 4.1 g Lys/Mcal ME based on G:F. In Exp. 2, increasing dietary SID Lys increased (linear, P < 0.01) ADG and G:F. Increasing dietary ME increased (linear, P < 0.01) G:F. Because of the linear responses in this experiment, optimal Lys:Mcal ratio was at least 4.0 g Lys/Mcal ME. In Exp. 3 (350 pigs; average BW = 9.4 kg; Source 1) and Exp. 4 (350 pigs; average BW = 7.5 kg; Source 2), Lys:Mcal ratios in Exp. 1 and 2 were compared by titrating Lys at 2 energy levels. Pigs were fed diets with either 2.95 or 3.29 Mcal ME/kg with SID Lys:Mcal ratios of 3.1 to 4.1 g/Mcal ME (Exp. 3) and 3.5 to 4.5 g/Mcal ME (Exp. 4). In Exp. 3, there was an ME x Lys:Mcal ratio interaction (P < 0.03) for ADG. The greatest ADG was a Lys:Mcal ratio of 3.60 for pigs fed low ME and a ratio of 3.35 for pigs fed high ME. Gain:feed ratio increased with increased (P < 0.01) ME concentration and as Lys:Mcal ratio increased (quadratic, P < 0.01); the best G:F was observed at 3.67 g Lys/Mcal ME. In Exp. 4, there was a tendency for ME x Lys:Mcal ratio interaction (P < 0.08) for G:F. The greatest G:F was achieved with a Lys: Mcal ratio of at least 4.50 for pigs fed low ME and a ratio of 4.29 for pigs fed high ME. Results (i.e., lack of ADG response to high energy density) suggest pigs reared in this environment were not in energy dependent growth phases. These pigs needed approximately 11 g/d of SID Lys (19 g Lys/kg gain) to optimize ADG and G:F. Based on these results, optimal Lys:Mcal ratio may differ depending on daily caloric intake of the pig.

Effect of extended withdrawal of zilpaterol hydrochloride on performance and carcass traits in finishing beef steers

Fri, 11 Sep 2009 07:21:51 PDT

The objective was to evaluate the effects of an extended withdrawal period after feeding the β-adrenergic agonist zilpaterol hydrochloride for 20 d at the end of the feeding period. Three hundred eighty-four crossbred beef steers were blocked by weight and randomly allocated into 64 pens (6 steers/pen). Pens were assigned to treatments in a 2 x 4 factorial arrangement in a randomized complete block design. Main effects were the addition of 0 (control) or 8.3 mg/kg zilpaterol hydrochloride (ZH; DM basis) to the finishing diet for 20 d before estimated average harvest date and paired withdrawal periods of 3, 10, 17, or 24 d prior to harvest. Individual BW was measured initially, 1 d prior to ZH feeding, and 1 d prior to harvest. The ZH feeding period was initiated so that control cattle in the 3-d withdrawal group would be expected to average 65% USDA Choice Quality Grade and have 1.27 cm of 12th-rib fat based on visual appraisal. Carcass data were collected at harvest. For the 3-d withdrawal steers, 2 steers from each pen were selected to determine visceral organ and total offal mass at harvest. The ZH x withdrawal day interaction was not significant (P > 0.10) for the majority of variables. There was no difference (P ≥ 0.12) due to ZH feeding for final BW, carcass-adjusted final BW, or ADG. However, DMI was decreased (P = 0.02) and G:F increased (P = 0.01) in steers fed ZH vs. control steers. As day after withdrawal of ZH increased, there was a linear increase (P < 0.001) in final BW and carcass-adjusted final BW, but a linear decrease (P < 0.001) in ADG over the finishing period and over the ZH plus withdrawal period. Overall, HCW was 380 and 369 kg (P < 0.001) for ZH and control steers, respectively. However, the difference between ZH and control was 14, 17, 5, and 6 kg with 3, 10, 17, and 24 d withdrawal, respectively (ZH x withdrawal d, P = 0.09). Feeding ZH increased dressing percentage (65.8 vs. 64.6%; P < 0.001) and LM area (94.8 vs. 89.7 cm²; P < 0.001), and decreased calculated yield grade (2.69 vs. 2.91; P=0.03) and percentage of cattle grading USDA Choice (31.1 vs. 42.3%; P = 0.03) compared with controls. Small intestinal mass (g/kg EBW) was greater (P = 0.03) for steers fed ZH compared with controls. There were no other differences (P ≥ 0.11) in mass of body components, expressed in kg or as a fraction of EBW. In this experiment, improvements in animal performance and HCW due to feeding ZH were generally maintained when withdrawal was extended through 10 d.

Fall growth, nutritive value, and estimation of TDN for cereal-grain forages in the north-central United States

Coblentz, W. K., Walgenbach, R. P. — Fri, 11 Sep 2009 07:21:50 PDT

Throughout the Southern Great Plains, wheat is managed frequently as a dual-purpose crop, but this production paradigm is not necessarily applicable throughout other regions of the United States, and a wider array of management options can be considered for forage-only uses of cereal grains. Our objectives were to assess the fall-growth potential of wheat (Triticum aestivum L.), triticale (X Triticosecale Wittmack), and oat (Avena sativa L.) cultivars in Wisconsin, and then to further evaluate and compare the fiber composition and TDN of these fall-grown forages. For 2006, yields of DM for all cultivars increased quadratically (P ≤ 0.048) over fall harvest dates, reaching a maximum of 3,967 kg/ha for Ogle oat. All oat cultivars exhibited stem elongation, and also displayed a collective 2 to 1 yield advantage over vegetative wheat cultivars on the final (30 October) harvest date. Growing conditions were more favorable during 2007, and yields were improved for all cultivars. Yields of DM for all cultivars increased quadratically (P ≤ 0.021) across harvest dates, and oat cultivars maintained the identical 2 to 1 yield advantage over wheat cultivars (6,275 vs. 3,203 kg/ha) that was observed for 2006. Triticale exhibited yields intermediate between oat and wheat during both years. Concentrations of NDF increased quadratically (P ≤ 0.012) across harvest dates for all cultivars during both years of the experiment; however, these increases occurred primarily between mid September and early October with limited responses thereafter. Oat and triticale cultivars had greater (P < 0.001) concentrations of NDF than wheat cultivars on 5 of 6 harvest dates throughout the experiment. Estimates of TDN exhibited various polynomial responses to harvest date during 2006, but the magnitude of these changes was relatively small. During 2007, TDN declined linearly (P ≤ 0.038) for grain-type oat, but no relationship with harvest date was observed for other cultivars (P ≥ 0.072), including forage-type oat. Although TDN estimates generally were relatively static across harvest dates, the concentrations of truly digestible components comprising the total TDN pool were quite fluid. Generally, reductions of truly digestible CP were offset by increases in truly digestible nonfiber carbohydrate, truly digestible fiber or both. The relatively stable energy densities for cereal-grain cultivars observed across harvest dates suggest that a broad window of opportunity exists for usage, including a single harvest as silage.

Genetic relationships among calving ease, gestation length, and calf survival to weaning in the Asturiana de los Valles beef cattle breed

Cervantes, I., Gutierrez, J. P., Fernandez, I., Goyache, F. — Fri, 11 Sep 2009 07:21:50 PDT

The aim of this paper was to estimate the genetic relationships among calving ease (CE), calf survival (CS), and gestation length (GL) in order to assess the possibility of including this information in beef cattle breeding programs. A total of 35,395 field records were available for CE, 30,684 for GL, and 36,132 for CS from the Asturiana de los Valles beef cattle breed. The 3 traits were analyzed as traits of the calf fitting a multivariate linear mixed model. Estimates of heritability (± SE) for the direct genetic effects (CEd, GLd, and CSd) were 0.325 ± 0.022, 0.331 ± 0.026, and 0.226 ± 0.018, respectively, whereas the estimates for maternal genetic effects (CEm, GLm, and CSm) were 0.066 ± 0.018, 0.066 ± 0.017, and 0.034 ± 0.011. The estimates for the ratio of permanent environmental variance to phenotypic variance were CEc 0.090 ± 0.011, GLc 0.066 ± 0.011, and CSc 0.024 ± 0.007. Genetic correlations between direct, maternal genetic, or permanent environmental effects involving CE and GL were, in general, positive and moderate, whereas those involving CE and CS were high. All were significant except for the pair CEm-GLm (0.277 ± 0.172). Correlations between GL and CS were non-significant. Genetic correlations for CEd-CEm, GLd-GLm, and CSd-CSm were negative and high, ranging from - 0.461 ± 0.120 for GLd-GLm to - 0.821 ± 0.145 for CSd-CSm. The genetic correlations for CEd-CSm and for CSd-CEm were negative, significant, and high, whereas that for GLd-CEm was moderate (- 0.323 ± 0.124) and that for GLd-CSm was non-significant. The genetic correlations for GLm with the direct effects of the other traits were non-significant. Strong selection for CE will result in a significant correlated response in CS. Therefore, CE can be considered an early indicator of CS performance. The benefit of using GL as a correlated trait in a genetic evaluation with CE and CS seems limited.

Association analyses of candidate SNP on reproductive traits in swine

Fri, 11 Sep 2009 07:21:50 PDT

The ability to identify young females with superior reproduction would have a large economic impact on commercial swine production. Previous studies have discovered SNP associated with economically important traits such as litter size, growth rate, and feed intake. The objective of this study was to test for association of candidate SNP with sow prolificacy reproductive traits in gilts of a Landrace-Duroc-Yorkshire composite population. Association analyses regressed additive (A), dominant (D), and imprinting (I) SNP effects on each trait with an animal model. A carnitine palmitoyltransferase 1A SNP and a glycogen synthase 1 SNP were associated with age at puberty (AP; D = 10 d; P = 0. 0037 and A = 3.8 d; P = 0.0078, respectively). Four IGF2 SNP were associated with AP as well, having additive or dominant effects (3.2 to 5.8 d; P < 0.0052). Two mannosidase 2B2 SNP and 2 prolactin receptor (PRLR) SNP were also associated with AP. Solute carrier 22, subfamily member 5 SNP was weakly associated with AP (D = 3.9 d; P < 0.10). Polymorphisms within glycogen synthase 1 and protein kinase AMP-activated, gamma 3 non-catalytic subunit had associations with ovulation rate. Estrogen receptor (ESR) 1, ESR2, peroxisome proliferator-activated receptor, gamma, coactivator 1, and IGFBP3 SNP were significantly associated with weaning-to-estrus interval. Two PRLR SNP were associated with total number of piglets born (A = 0.57 piglets; P = 0.0095 and D = 0.61 piglets; P = 0.0016, respectively). A SNP within PRLR was also associated with number of piglets born alive (D = 0.61; P = 0.0016). Peroxisome proliferator-activated receptor, gamma, coactivator 1 SNP was associated with total number of piglets born (D = 0.38 piglets; P = 0.0391) and number of piglets born alive (D = 0.53 piglets; P = 0.0032). SNP within ESR1 (A = 0.65 piglets; P =0.0950), ESR2 (A = -0.33 piglets; P = 0.0176), IGF2 SNP (A = -0.26 piglets; P = 0.0032), and IGFBP3 SNP (D = 0.35 piglets; P = 0.0683) were associated with number of piglets born dead. A leptin SNP was associated with mummified fetuses (D = 0.09 piglets; P = 0.0978). Many of the SNP analyzed in this study are from genes involved in regulation of metabolism, suggesting that there is an important link between physiological events associated with reproduction and energy utilization. Furthermore, these production and growth trait SNP may serve to assist in selection of young females for superior reproductive performance.

Fine mapping of quantitative trait loci for meat color on SSC6: analysis of the swine NUDT7 gene

Fri, 11 Sep 2009 07:21:49 PDT

In the livestock industry meat color has become important, because consumer acceptance is subject to the appearance of the product in the market place. Our previous analyses of a whole genome QTL scan for various meat qualities using 2 F₂ families from Japanese wild boar (known as a red meat) x Large White, and from Duroc x Chinese Jinhua suggested that a meat color (heme content) QTL is located on SSC6. The objective of this study was to fine-map this SSC6 meat color QTL, and subsequently investigate positional candidate genes for polymorphisms that may cause changes in meat color. Therefore, we conducted interval mapping on SSC6 using an additional 9 gene markers through combined analyses of the 2 F₂ families of Japanese wild boar x Large White (353 progeny) and Duroc x Chinese Jinhua (204 progeny). Comparative analysis with humans, mice, and cattle suggested that there were 10 functional genes in the region. Among these genes, we suggested that a novel pig gene encoding a nudix (nucleoside diphosphate linked moiety X)-type motif 7 (NUDT7, a member of the nudix hydrolases) is a strong candidate for the QTL, because the mouse Nudt7 is reported to hydrolyze succinyl-CoA, a substrate of the reaction limiting the rate of heme biosynthesis. We therefore determined the pig NUDT7 gene sequence including the 5' promoter region and explored genetic polymorphisms between Japanese wild boar and Large White. We identified 116 polymorphisms either within the NUDT7 CDS, or in the 5’ region. None of the amino acid substitutions were associated with the meat color QTL; however, 3 polymorphisms were found in putative transcription factor recognition sites. We then investigated the differential expression of NUDT7 in Japanese wild boar and Large White by allele-specific quantitative real-time PCR. The expression level of the Large White type allele was higher than that of the Japanese wild-boar-type allele. Consequently, we speculated that the difference in meat color between Japanese wild boar and Large White is caused partly by differential expression of this candidate gene. Upregulation of NUDT7 expression in muscle may reduce succinyl-CoA content and thus lower the level of heme biosynthesis.

A New Approach to Sperm Preservation Based Upon Bioenergetic Theory

Froman, D. P., Feltmann, A. J. — Fri, 11 Sep 2009 07:21:49 PDT

To date, attempts to preserve chicken sperm have been based upon a trial-and-error experimental approach. The present work outlines the development of an alternative approach based upon empiricism and bioenergetic theory. In previous work, fowl sperm motility was dependent upon mitochondrial calcium cycling, phospholipase A₂, and long-chain fatty acids as an endogenous energy source. It is noteworthy that fowl sperm reside with the oviduct’s sperm storage tubules (SST) over an interval of days to weeks after insemination. In this regard, a model for in vivo sperm storage was developed and tested in additional previous research. Sperm penetration of the SST, sperm residence within the SST, and sperm egress from the SST can be explained in terms mitochondrial function. Understanding sperm function and longevity in terms of bioenergetics presented the possibility that sperm could be inactivated by disrupting mitochondrial c)alcium cycling and thereby preserved. However, this possibility also posed a problem: maintenance of the mitochondrion’s inner membrane potential within inactivated sperm. This report describes a series of experiments in which fowl sperm were inactivated by treatment with the calcium chelator, tetrasodium 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), and then reactivated by treatment with calcium ions. The effect of BAPTA upon mitochondrial calcium cycling was confirmed by flow cytometry and confocal microscopy. When treated sperm were cooled to 10ºC, inactivated sperm could be reactivated throughout a 5-h storage interval. When stored sperm were held for 3 h prior to reactivation and insemination, fertility was 88% of the control. Storage did not affect hatchability. In summary, short-term storage was realized by manipulating mitochondrial function. We propose: 1) Complex V consumes ATP within inactivated sperm and by doing so maintains the mitochondrion’s inner membrane potential, 2) ATP is regenerated within inactivated sperm by the action of creatine kinase upon phosphocreatine, and 3) necrosis follows depletion of intracellular phosphocreatine. Therefore, future attempts to preserve chicken sperm can be based upon a theory that encompasses regulation of energy production, a biological context in which sperm cells are motile, and the consequences of mitochondrial failure.

Genomic selection in admixed and crossbred populations

Toosi, A., Fernando, R. L., Dekkers, J. C. M. — Fri, 11 Sep 2009 07:21:48 PDT

In livestock, genomic selection (GS) has primarily been investigated by simulation of purebred populations. Traits of interest are, however, often measured in crossbred or mixed populations with uncertain breed composition. If such data are used as the training data for GS without accounting for breed composition, estimates of marker effects may be biased due to population stratification and admixture. To investigate this, a genome of 100 cM was simulated with varying marker densities (5 to 40 segregating markers per cM). After 1,000 generations of random mating in a population of effective size 500, four lines with effective size 100 were isolated and mated for another 50 generations to create 4 pure breeds. These breeds were used to generate combined, F₁, F₂, 3- and 4-way crosses, and admixed training data sets of 1,000 individuals with phenotypes for an additive trait controlled by 100 segregating QTL and heritability of 0.30. The validation data set was a sample of 1,000 genotyped individuals from one pure breed. Method Bayes-B was used to simultaneously estimate the effects of all markers for breeding value estimation. With 5 (40) markers per cM, the correlation of true with estimated breeding value of selection candidates (accuracy) was highest, 0.79 (0.85), when data from the same pure breed was used for training. When the training dataset consisted of crossbreds, the accuracy ranged from 0.66 (0.79) to 0.74 (0.83) for the 2 marker densities, respectively. The admixed training dataset resulted in nearly the same accuracies as when training was in the breed to which selection candidates belonged. However, accuracy was greatly reduced when genes from the target pure breed were not included in the admixed or crossbred population. This implies that, with high-density markers, admixed and crossbred populations can be used to develop GS prediction equations for all pure breeds that contributed to the population, without a substantial loss of accuracy compared to training on purebred data, even if breed origin has not been implicitly taken into account. In addition, using GS based on high-density marker data, purebreds can be accurately selected for crossbred performance without the need for pedigree or breed information. Results also showed that haplotype segments with strong linkage disequilibrium are shorter in crossbred and admixed populations than in purebreds, providing opportunities for QTL fine mapping.

Performance, residual feed intake, digestibility, carcass traits and profitability of Angus-Hereford steers housed in individual or group pens

Cruz, G. D., Rodriguez-Sanchez, J. A., Oltjen, J. W., Sainz, R. D. — Fri, 11 Sep 2009 07:21:47 PDT

Even though the concept of residual feed intake (RFI) is well accepted, several questions remain regarding other traits that may be associated with selection for lower RFI. These include DM digestibility, carcass composition, profitability, and performance. The objective of this study was to investigate the difference in those traits between low- and high-RFI cattle. Sixty Angus x Hereford crossbred steers (296 kg initial BW) were fed a corn-based finishing ration (1.68 Mcal NE_m/kg, 13% CP on a DM basis) during 2 periods of 60 d each. For both phases, the regression equation fitted without the intercept (not statistically significant) was: DMI (kg/d) = 0.0701 x BW^0.75 + 2.714 x ADG, r² = 0.42. The 15 highest and lowest RFI steers were classed as High and Low RFI groups. There were no differences between Low and High RFI groups for days on feed (162 vs. 168 d), slaughter weight (503 vs. 511 kg), HCW (317 vs. 315 kg), LM area (76.5 vs. 77.1 cm²), backfat (1.23 vs. 1.27 cm), KPH (3.1 vs. 3.7%), quality grade (average Choice for both groups), or carcass fat (32.4 vs. 33.1%). Visceral organ masses and abdominal fat were similar for Low and High RFI groups (32.25 vs. 31.24 kg and 37.48 vs. 36.95 kg, respectively). These results do not support the existence of major differences in composition and organ mass between Low and High RFI steers at harvest. The RFI grouping had a significant effect on DMI, G:F, and RFI values. Stepwise regression showed that G:F alone or DMI and ADG together explained 98.5% of the variance in cost of gain, whereas RFI alone explained only 18%. We conclude that RFI is less useful than G:F as an indicator of feedlot efficiency and profitability.

Effects of water quality and dietary potassium on performance and carcass characteristics of yearling steers

Sexson, J. L., Wagner, J. J., Engle, T. E., Spears, J. W. — Fri, 11 Sep 2009 07:21:47 PDT

Four hundred thirty-two crossbred yearling steers (339 kg ± 4.8) were used to investigate the effects of water quality and dietary potassium (K) concentration and source on feedlot performance and carcass merit. The study was conducted using a 2 x 3 factorial treatment arrangement. Factors evaluated included 2 water sources: 1) a blend of reverse osmosis and well water (RO; 608 ± 164 mg/L SO₄) and 2) 100% well water high in SO₄ concentration (1,933 ± 53 mg/L SO₄) and 3 dietary K treatments. Potassium treatments included: 0.75% K with supplemental K from potassium chloride (0.75% K - KCl), 0.75% K with supplemental K from potassium carbonate (0.75% K - K₂CO₃), and 1.0% K with supplemental K from potassium carbonate (1.0% K - K₂CO₃). Interactions between water quality and dietary treatments were not significant. Dry matter intake tended (P = 0.10) to be greater for steers consuming RO water compared to well water and was not affected by dietary treatment. Feed efficiency (P = 0.04) and NE_g recovery (P = 0.04) were greater for 1.0% K - K₂CO₃ compared with 0.75% K - KCl but were not affected by water quality. Final weight was heavier (P < 0.001) and ADG was greater (P = 0.04) for RO water compared to well water but were not affected by diet. Carcasses from steers that consumed RO water tended (P = 0.08) to be heavier than carcasses from steers consuming well water. Dietary treatment did not affect HCW (P = 0.52). Yield Grade calculated from carcass measurements was not affected by dietary treatment or water quality. Carcasses from steers consuming well water had greater (P = 0.04) marbling scores than RO water. These data demonstrate that steers consuming RO water achieved improved feedlot performance. Steers fed 1.0% K - K₂CO₃ were more efficient and demonstrated improved energy recovery compared with steers fed 0.75% K - KCl. Improved efficiency and energy recovery may be related to a reduction (P = 0.06) in the liver abscess rate for steers consuming 1.0% K - K₂CO₃. Dietary cation-anion balance was positively related to ADG (P < 0.01) and NE_g (P = 0.03) recovery but negatively related to marbling score (P = 0.04).

Estimation of genetic and crossbreeding parameters for preweaning traits in German Angus and Simmental beef cattle, and the reciprocal crosses

Brandt, H., Mullenhoff, A., Lambertz, C., Erhardt, G., Gauly, M. — Fri, 11 Sep 2009 07:21:49 PDT

Data from pure breeds, as well as reciprocal crosses of German Angus (GA) and Simmental (ST) beef cattle, were used to estimate genetic parameters and to evaluate the suitability for crossbreeding in terms of increasing productivity. Traits of interest were calving difficulty, birth weight (BWT), weaning weight (WWT), and average daily gain (ADG) from birth to weaning. Data were collected over a period of 7 yr from 1997 and 1998 until 2003 and 2004, whereas crossbreeding was carried out in 2002 and 2003 and 2003 and 2004 only. Variance components and differences between breeds, individual heterosis, and maternal breed effects were analyzed based on 1,441 purebred and 329 crossbred records for BWT and 1,319 purebred and 316 crossbred records for WWT and ADG, respectively. Mean calving difficulty scores were higher in ST than in GA (P < 0.001). For BWT, WWT, and ADG both reciprocal crosses fell between the straightbreds and for all 3 traits ST showed higher average values compared to GA. The estimated heritabilities were 0.23 for BWT and 0.12 for WWT. Values for the maternal effect and the correlation between additive and maternal effect were 0.18 for BWT, 0.08 for WWT, 0.32 for BWT, and 0.50 for WWT, respectively. Individual heterosis was only significant for BWT (3.7%; P < 0.01). Superior mothering ability of ST was implicated by higher WWT and ADG of ST as dam against the reciprocal cross (P < 0.001). The results provide information about the extent of individual heterosis and maternal breed effects.

Whole Genome SNP associations with feed intake and feed efficiency in beef cattle

Sherman, E. L., Nkrumah, J. D., Moore, S. S. — Fri, 11 Sep 2009 07:21:47 PDT

Feed intake and efficiency are economically important traits as feed is the highest variable cost in beef production. Feed efficiency can be measured as residual feed intake (RFI), which is the difference between actual DMI of an animal and the expected DMI based on its weight and growth rate. Feed conversion ratio (FCR) is the inverse of gross feed efficiency, and is the ratio of DMI to ADG. A total of 2,633 SNP across the 29 bovine autosomes were analyzed in 464 steers sired by Angus, Charolais, or Alberta Hybrid bulls for associations with RFI. A total of 150 SNP were associated with RFI at P < 0.05 of which 23 were significant at P < 0.01. Nine of the SNP pairs show high linkage disequilibrium (LD, r²> 0.80), so only 1 of the SNP pairs was used in further multiple-marker analyses. Two methods were used to create a panel of SNP that were maximally informative for RFI based on the data. In the first method, 141 unique SNP were combined in a single multivariate model and a backward elimination model was used to drop SNP until all SNP left in the model were significant at P < 0.05. SNP had greater effects when combined in the multivariate model than when tested individually. In the second method, the estimates from the 141 SNP were used to create a sequential molecular breeding value (MBV) according to the compound covariate prediction (CCP) procedure. The sequential MBV was built by adding the estimated effects one at a time, but only keeping SNP effects in the sequential MBV if the test statistic and the proportion of variance explained were improved. Predictabilities of the 2 methods were compared by regressing RFI on a final MBV created from SNP that remained in each analytical model. The MBV from the CCP model produced an r² of 0.497, whereas the multivariate model MBV had a lower r² of 0.416. The significant SNP were also tested for associations with DMI and FCR. The SNP showed different combinations of associations with the 4 traits, including some that were only associated with RFI. About 9.5% of the SNP from the 2 models were within 5 cM of previously identified RFI QTL and pinpoint areas to further explore for positional candidate genes. In conclusion, this study has identified a panel of SNP with significant effects on RFI that need to be validated in an independent population, and provides continued progress towards selecting markers for use in marker-assisted selection for feed efficiency in beef cattle.

Effects of mannanase and distillers dried grain with solubles on growth performance, nutrient digestibility, and carcass characteristics of grower-finisher pigs

Fri, 11 Sep 2009 07:21:46 PDT

Four experiments were conducted to determine the effects of dietary supplementation of corn distillers dried grain with solubles (DDGS) diets with mannanase on performance, apparent total tract digestibility (ATTD) of energy and nutrients, blood metabolites and carcass characteristics of grower-finisher pigs. In Exp. 1, 96 grower pigs (initial BW, 57.6 kg), 6 pigs per pen and 4 pens per treatment, were fed corn-soybean meal-based diets containing 10% DDGS and 0, 200, 400, or 600 unit (U) mannanase/kg. The ADG and blood glucose increased (linear, P < 0.05) with increasing concentrations of dietary mannanase. Pigs fed diets containing increasing levels of mannanase had improved ATTD of DM and CP (quadratic, P < 0.05). In Exp. 2, 64 finisher pigs (initial BW, 92.7 kg) were allotted to 4 treatment groups with 4 pigs per pen and 4 pens per treatment. Pigs were fed corn-soybean meal-based diets containing 15% DDGS and 0, 200, 400, or 600 U mannanase/kg. Linear increasess (P < 0.05) in ADG, blood glucose and ATTD of DM, GE, and CP were observed with increasing levels of dietary mannanase supplementation. In Exp. 3, 208 grower pigs (initial BW, 60.5 kg) were allotted to 4 treatment groups with 13 pigs per pen and 4 pens per treatment. Pigs were fed diets containing 0 or 10% DDGS and 0 or 400 U mannanase/kg in a 2 x 2 factorial arrangement. An increase (P < 0.05) in ADG and blood glucose for pigs fed diets containing mannanase was observed. The ATTD of DM and CP (P < 0.05) was decreased with the inclusion of DDGS, whereas pigs fed the mannanase supplemented diets had an increased (P < 0.05) ATTD of CP. In Exp. 4, 208 finisher pigs (initial BW, 86.5 kg), with 13 pigs per pen and 4 pens per treatment, were fed diets containing 0 or 15% DDGS and 0 or 400 U mannanase/kg in a 2 x 2 factorial arrangement. The ADG and blood glucose increased (P < 0.05) when mannanase was included in the diets. The ATTD of DM (P < 0.05), GE (P < 0.10), and CP (P < 0.05) increased by the supplementation with mannanase in the diets of finisher pigs. The carcass characteristics and meat quality were not affected by the DDGS or mannanase inclusion. These results indicated that including 10 and 15% DDGS in conventional swine grower and finisher diets had no detrimental effects on growth performance or carcass characteristics. In addition, supplementation with 400 U of mannanase/kg diets containing 10 and 15% DDGS fed to grower and finisher pigs may improve growth performance and the ATTD of CP.

Energy cost of activities and locomotion of grazing cows: a repeated study in larger plots

Fri, 28 Aug 2009 11:18:56 PDT

We determined the energy costs associated with the activities of beef cows grazing on Mediterranean foothill rangeland covered with herbaceous vegetation. Our central aim was to compare the energy cost coefficients obtained in this study, using relatively large plots, with those obtained in a previous study conducted on smaller plots. Measurements were performed in 3 seasons: in March on nursing cows grazing a 135-ha plot of high quality herbage (11.4 MJ/kg ME); and in May and September on non-lactating cows grazing a 78-ha plot of low quality herbage (6.2 MJ/kg ME). Poultry litter manure was given as a supplement in September. Stocking rates on the respective plots were 2.25 and 1.95 ha/cow; 5, 5, and 7 cows were monitored in the respective months. Heat production was determined by continuous monitoring of the heart rate and measurement of the oxygen consumption per heart beat. Animal location was tracked with Global Positioning System (GPS) collars equipped with motion sensors. Activity was determined for 5-min intervals using suitable calibration equations. Horizontal and vertical distances traveled were computed by integrating GPS data and plot maps in a Geographic Information System. Three models were used to estimate the energy cost coefficients of engaging in a given activity and locomotion. Total daily heat production ranged from 644 (September) to 1,014 kJ • kgBW^-0.75 • d^-1 (March) (P = 0.04). Estimates of the energy cost coefficients for activity states (kJ • kgBW^-0.75• d^-1) ranged from 42.7 to 46.2 for standing, from 84.5 to 92.4 for walking idle, and from 89.4 to 103.2 for grazing; those for locomotion (kJ • kgBW^-0.75• d^-1 • km^-1) ranged from 2.8 to 2.9 for horizontal locomotion and from 21.4 to 27.9 for vertical locomotion. Estimated cost coefficients of standing, grazing, and horizontal locomotion derived in the present study from animals on relatively larger plots were similar to those of the previous study based on data from smaller plots, but the energy costs of walking idle and of vertical locomotion were greater in the present study than in the previous one. The differences found are associated with the fact that cows in the present study walked for longer periods of time and traveled longer distances in single uninterrupted bouts of locomotion than those in the previous study.

Fetal Programming of Skeletal Muscle Development in Ruminant Animals

Fri, 28 Aug 2009 11:18:54 PDT

Enhancing skeletal muscle growth is crucial for animal agriculture because skeletal muscle provides meat for human consumption. An increasing body of evidence shows that the level of maternal nutrition alters fetal skeletal muscle development with long-term effects on offspring growth and performance. Fetal skeletal muscle development mainly involves myogenesis (i.e., muscle cell development), but also involves adipogenesis (i.e., adipocyte development) and fibrogenesis (i.e., fibroblast development). These tissues in fetal muscle are mainly derived from mesenchymal stem cells (MSC). Shifting the commitment of MSC from myogenesis to adipogenesis increases intramuscular fat (i.e., marbling) improving the quality grade of meats. Strong experimental evidence indicates that Wingless and Int (Wnt)/β-catenin signaling regulates MSC differentiation. Up-regulation of Wnt/β-catenin promotes myogenesis and down-regulation enhances adipogenesis. Lack of nutrients during early to mid-gestation reduces the formation of secondary muscle fibers in ruminant animals. Nutrient deficiency during mid- to late gestation decreases the number of intramuscular adipocytes and muscle fiber sizes. Knowledge of this regulatory mechanism will enhance muscle growth and marbling in offspring especially in the setting of nutrient deficiency.

Synergistic effects of betaine and conjugated linoleic acid on growth and carcass composition of growing Iberian pigs

Tue, 02 Oct 2007 08:41:27 PDT

An experiment was conducted to determine the efficacy of dietary betaine, conjugated linoleic acid or both as growth promotants and carcass modifiers in growing Iberian pigs. Twenty gilts (20 kg BW) were individually penned and fed barley-soybean meal based diets (12% CP, 0.81% lysine and 14.8 MJ ME/kg DM) containing either no added betaine or conjugated linoleic acid (control), 0.5% betaine, 1% CLA, or 0.5% betaine + 1% CLA, at 95% ad libitum energy intake. An additional group of 5 pigs was slaughtered at the beginning of the experiment to obtain initial body composition. At 30 kg BW, a balance experiment was conducted. At 50 kg, pigs were slaughtered and viscera was removed and weighed. Betaine or CLA alone did not affect growth performance. However, betaine + CLA increased ADG (601 vs. 558 g, P = 0.03) and gain relative to ME intake (25.4 vs. 22.2 g/MJ, P = 0.03) compared to control pigs. Digestibility of nutrients and metabolizability of energy did not differ among diets (P = 0.46 to 0.75). Carcass gain numerically increased (388 vs. 424 g/d; P = 0.13) when pigs were fed betaine + CLA compared to the control diet. Protein, water and lean deposition (g/d) increased (19.8, 24.2 and 23.4%, respectively, P < 0.01) in betaine + CLA fed pigs compared to control pigs. Similarly, protein deposition relative to ME intake increased by 28% in betaine + CLA supplemented pigs (P < 0.05). Fat and mineral deposition did not differ among treatments. Carcass protein, water and lean content (g/kg carcass) of pigs fed betaine + CLA supplemented diets tended to increase (P = 0.07 to 0.09) and carcass fat content tended to decrease (P = 0.09). Similarly, estimated composition of carcass gain was affected such that water and lean tended to increase (P = 0.06 to 0.08) while fat tended to decrease (P = 0.08) in pigs fed betaine + CLA supplemented diets. Carcass drip loss numerically increased (P = 0.12) and 10^th-rib backfat at P1 numerically decreased (P = 0.12) in pigs fed betaine + CLA diets. Longissimus muscle area was not altered by treatments (P = 0.49). Liver of pigs fed betaine + CLA diets had increased weight (19%, P < 0.05) compared to control pigs. Overall, dietary supplementation of betaine + CLA increased ADG, protein, water and lean deposition in growing Iberian gilts. There appears to be a synergism of action when betaine and CLA are used together.

Evaluation of secondary protein nutrients as a substitute for soybean meal in diets for beef steers and meat goats

Freeman, S. R., Poore, M. H., Huntington, G. B., Middleton, T. F. — Tue, 02 Oct 2007 08:41:26 PDT

Finding appropriate disposal techniques for waste products is one of many challenges facing the poultry processing industry. One waste generated in significant quantities is dissolved air floatation sludge, a product of wastewater treatment. Converting dissolved air floatation sludge into a dry feed product (meal) for incorporation into livestock feed appears to be a viable solution. This meal, called secondary protein nutrients (SPN), is high in protein (45% CP), fat (28% crude fat), and minerals. The protein consists of 85% B₂ and B₃ fractions, which are moderately to slowly degradable in the rumen and therefore may potentially escape ruminal degradation and be available for digestion in the lower gastrointestinal tract. The goal of this research was to evaluate SPN as an alternative to traditional protein sources for ruminants by substituting it on equal N basis for soybean meal in cattle and meat goat diets (0, 25, 50, 75, and 100% for cattle; 0, 20, and 40% for goats). When included in corn silage-based steer diets, increasing SPN resulted in linear and quadratic declines in both DMI and ADG (P < 0.001). Dry matter intake diminished with inclusion rates above 50%, and ADG were reduced after inclusion of SPN reached 25% of added N. Feed efficiency declined linearly (P < 0.001) with each incremental increase in SPN. Addition of up to 40% of added N as SPN in goat diets caused no change in DMI, digestibility of DM or fiber, or N retention. Ruminal VFA concentrations showed little variation in either species. Increasing the proportion of SPN in the feed caused linear declines in ruminal NH₃ in steers (P < 0.001). Increasing SPN in goat diets, however, resulted in only a trend towards reductions of this parameter (P = 0.14). The decreases observed may have resulted from decreasing ruminal protein degradability or increasing fat caused by increasing the proportion of SPN in the feed. Urinary urea N as a percentage of urinary N showed significant declines in urinary urea N as a percentage of urinary N in cattle, but not in goats, over the ranges of SPN offered. These results indicate that SPN can be included in diets for ruminants to supply up to 40% of supplemental N with little negative impact on animal performance.

Effect of recombinant human FSH and LH on in vitro maturation of porcine oocyte evaluated by the subsequent in vitro development of embryos obtained by in vitro fertilization, intracytoplasmic sperm injection or parthenogenetic activation

Mon, 04 Dec 2006 11:55:47 PST

The aim of this work was to study the effect of recombinant human (rh) FSH and LH on in vitro maturation of pig oocytes in comparison with a conventional hormonal supplement based on equine (PMSG) and human chorionic gonadotropins (hCG) evaluated by the developmental ability of three types of pig embryos obtained by in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) or artificial activation (AA). In Exp. 1, one cumulus oocyte complex (COC) group (A group) was supplemented with 0.1 IU/mL rh-FSH and -LH, and the other group (B group) was supplemented with 10 IU/mL PMSG and hCG. No significant differences in nuclear maturation between A- and B-group were observed (68.5 vs. 71.4 %, respectively). No significant differences between hormonal treatments in cleavage or blastocyst rates of AA, IVF and ICSI embryos were detected. Total cell number of embryos was not significantly different in any experimental group (A: 31.1, 28.5 and 19.8 vs. B: 25.2, 25.5 and 20.6 to AA, IVF and ICSI embryos, respectively). In Exp. 2, effects of different hormonal concentrations of rh-FSH and -LH (0.5, 0.1 and 0.05 IU/mL) in maturation medium on nuclear maturation and in vitro development of embryos obtained by IVF were studied. No effect of different hormonal concentrations on blastocyst rates was observed (8.5, 13.0 and 5.7%, respectively). Blastocyst cell number was not significantly different in any experimental group. In conclusion, results obtained here permit us to substitute PMSG and hCG by rh-FSH and -LH and to produce pig embryos obtained by IVF, ICSI or AA.