Current issue only

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

Wed, 27 Jan 2010 16:51:48 PST

The association of the 2464G > A SNP found in the promoter region of the rabbit progesterone receptor gene with progesterone receptor (PR) 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 uterine capacity. Two progesterone isoforms were obtained using a commercial monoclonal antibody: the PR-B isoform described previously in rabbits, and the PR-A isoform, not described previously in rabbits. The GG genotype, the genotype more frequent in the high line, showed less 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 less 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.

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. — Wed, 27 Jan 2010 16:51:48 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 by 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. A total of 643 were animals genotyped at codon 171 of the PrP gene with 2 alleles, R and Q. The genotypes of these animals were used to predict the genotypes of 5,173 nongenotyped animals in the same flock using segregation analysis. The genotype of nongenotyped 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 animals with both known and inferred genotypes) with BW 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 nongenotyped animals). Approximately 25% of the 5,173 predicted genotypes were inferred with a genotype probability index of 50% and greater. There was no significant association of the 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 with both known and predicted genotypes were considered. It can be concluded that selection for PrP-resistant alleles in Suffolk sheep is unlikely to affect performance directly.

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

Wed, 27 Jan 2010 16:51:48 PST

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, LM area, backfat thickness, and rump fat thickness obtained by ultrasound. Two SNP 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 (Sertãozinho, Brazil). 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 greater in the control line than in the selected lines. The DGAT1 K232A mutation was associated only with rump height, whereas 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.

Technical note: Efficient protocol for isolation of total ribonucleic acid from lyophilized fat and muscle pig samples

Pena, R. N., Canovas, A., Estany, J. — Wed, 27 Jan 2010 16:51:48 PST

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

The two mutations, Q204X and nt821, of the myostatin gene affect carcass and meat quality in young heterozygous bulls of French beef breeds

Wed, 27 Jan 2010 16:51:48 PST

The availability of genetic tests to detect different mutations in the myostatin gene allows the identification of heterozygous animals and would warrant the superiority of these animals for slaughter performance if this superiority is confirmed. Thus, 2 mutations of this gene, Q204X and nt821, were studied in 3 French beef breeds in the program Qualvigène. This work was done with 1,114 Charolais, 1,254 Limousin, and 981 Blonde d’Aquitaine young bulls from, respectively, 48, 36, and 30 sires and slaughtered from 2004 to 2006. In addition to the usual carcass traits recorded at slaughter (e.g., carcass yield, muscle score), carcass composition was estimated by weighing internal fat and dissecting the 6th rib. The muscle characteristic traits analyzed were lipid and collagen contents, muscle fiber section area, and pH. Regarding meat quality, sensory qualities of meat samples were evaluated by a taste panel, and Warner-Bratzler shear force was measured. Deoxyribonucleic acid was extracted from the blood samples of all calves, the blood samples of 78% of the dams, and the blood or semen samples of all the sires. Genotypes were determined for 2 disruptive mutations, Q204X and nt821. Analyses were conducted by breed. The superiority of carcass traits of calves carrying one copy of the mutated allele (Q204X or nt821) over noncarrier animals was approximately +1 SD in the Charolais and Limousin breeds but was not significant in the Blonde d’Aquitaine. In the Charolais breed, for which the frequency was the greatest (7%), young bulls carrying the Q204X mutation presented a carcass with less fat, less intramuscular fat and collagen contents, and a clearer and more tender meat than those of homozygous-normal cattle. The meat of these animals also had slightly less flavor. Also in the Charolais breed, 13 of 48 sires were heterozygous. For each sire, the substitution effect of the wild allele by the mutant allele was approximately +1 SD for carcass conformation and yield, showing that the estimate of the substitution effect was independent of family structure, as it ought to be for a causal mutation. These results illustrate the challenge of using genetic tests to detect animals with the genetic potential for greater grades of carcasses and meat quality.

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

Holl, J. W., Rohrer, G. A., Brown-Brandl, T. M. — Wed, 27 Jan 2010 16:51:48 PST

Genetic parameters for scale activity score (AS) were estimated from generations 5, 6, and 7 of a randomly selected, composite population composed of Duroc, Large White, and 2 sources of Landrace (n = 2,186). At approximately 156 d of age, pigs were weighed (BW) and ultrasound backfat measurements (BF1, BF2, and BF3) were done. While pigs were in the scale, an 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 BW or BW for BF1, BF2, and BF3, and an animal direct genetic effect. A 5-trait linear mixed model was used. Estimated heritabilities were 0.23, 0.54, 0.56, 0.52, and 0.48 for AS, BW, BF1, BF2, and BF3, respectively. Estimated genetic correlations between AS and BW, 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 BW were negative, as was the genetic correlation of AS with BW. Therefore, selection for more docile animals would be expected to result in fatter, faster growing pigs.

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. — Wed, 27 Jan 2010 16:51:48 PST

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 multibreed 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, maternal effects, direct heterosis effects, and maternal heterosis effects for growth and carcass traits using least squares means estimates from crossbreeding studies published in the literature from 1976 to 1996. The data set was formed by recording each least squares 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 breed effects for weaning weight ranged from –7.0 ± 0.67 kg (British Dairy) to 29.3 ± 0.74 kg (Simmental), and maternal effects ranged from –11.7 ± 0.24 kg (Hereford) to 31.1 ± 2.22 kg (Gelbvieh). Direct breed effects for birth weight ranged from –0.5 ± 0.14 kg (British Dairy) to 10.1 ± 0.46 kg (Continental Beef), and maternal effects ranged from –7.2 ± 0.13 kg (Brahman) to 6.0 ± 1.07 kg (Continental Beef). Direct breed effects 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 postweaning BW gain, carcass weight, LM 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 multibreed evaluation.

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

Lewis, R. M., Emmans, G. C. — Wed, 27 Jan 2010 16:51:48 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 2 experimental lines (n = 225) and from 3 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 greater 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 2 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 feed, for the spline regression, u* varied little around 0.434 (SD = 0.020) for the 10 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 6 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.

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. — Wed, 27 Jan 2010 16:51:48 PST

The objective of this study was to infer (co)variance components for piglet survival at birth in purebred and crossbred pigs. Data were from 13,643 (1,213 litters) crossbred and 30,919 (3,162 litters) purebred pigs, produced by mating the same 168 purebred boars to 460 Large White-derived crossbred females and 1,413 purebred 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 purebred were 0.018 (0.008) and 0.077 (0.020), respectively. For crossbred, 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 purebred and crossbred and of the genetic correlation between these traits were 0.049 (0.023), 0.091 (0.054), and 0.248 (0.336), respectively. The greatest 95% confidence region (–0.406, 0.821) for the genetic correlation between purebred and crossbred liabilities of piglet survival included zero. Results suggest that the expected genetic progress for piglet survival in crossbreds when selection is based on purebred information may be nil.

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. — Wed, 27 Jan 2010 16:51:48 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 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 steers. Animals treated for BRD had decreased yield grades (P = 0.003 and P = 0.02, in GPE7 and GPE8, respectively) compared with untreated animals. Animals treated for IPD had decreased yield grades (P = 0.0006 and P = 0.004, in GPE7 and GPE8, respectively) compared with untreated animals. Incidence of BRD and IPD were associated with a reduction in fat thickness in GPE7 and GPE8 steers. Animals treated for BRD had reduced adjusted fat measurements (P = 0.0007 and P = 0.01, in GPE7 and GPE8) compared with untreated animals. Animals treated for IPD also had reduced adjusted fat measurements (P = 0.0003 and P = 0.002, in GPE7 and GPE8) compared with untreated animals. Animals treated for BRD (P < 0.007) or IPD (P < 0.02) in the GPE7 population also had decreased estimated KPH measurements compared with unaffected animals. Animals affected with BRD in GPE8 had greater (P < 0.05) shear force measurements than unaffected animals. Animals affected with IPD in GPE8 had greater HCW (P < 0.03) and fat yield (P < 0.01) measurements but lesser bone yield (P < 0.03) and retail product yield (P < 0.01) 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.

Technical note: An R package for fitting generalized linear mixed models in animal breeding1

Vazquez, A. I., Bates, D. M., Rosa, G. J. M., Gianola, D., Weigel, K. A. — Wed, 27 Jan 2010 16:51:48 PST

Mixed models have been used extensively in quantitative genetics to study continuous and discrete traits. A standard quantitative genetic model proposes 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 mixed models with correlated random effects to be fitted for Gaussian, binary, and count responses. Following the method of 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 REML. This note describes the classes of models that can be fitted using pedigreemm and presents examples that illustrate its use.

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. — Wed, 27 Jan 2010 16:51:48 PST

Pedigree information was 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). 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). The average kinship coefficients between rams from which semen doses are available in the French National Cryobank and the active ram and ewe populations were also computed. Results found in each breed were analyzed by taking into consideration the demographic evolution of the breeds, their management practices, and the use of cryopreservation as a way to preserve genetic variability. It appeared quite clear that, in populations in which AI with frozen semen is seldom used, factors that mainly affect the genetic variability are the female-to-male ratio, which should be as small as possible, and the number of reproducing female offspring by males, 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.

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. — Wed, 27 Jan 2010 16:51:48 PST

The objectives were to estimate genetic parameters needed to elucidate the relationships of a molecular breeding value (MBV) for marbling, intramuscular fat (IMF) of yearling bulls measured with ultrasound, and marbling score (MRB) of slaughtered steers, and to assess the utility of MBV and IMF in predicting the breeding value for MRB. Records for MRB (n = 38,296) and IMF (n = 6,594) were from the American Angus Association database used for national cattle evaluation. A total of 1,006 records of MBV were 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 a greater genetic advance of approximately 20% when used as an indicator trait for genetic prediction of MRB compared with 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 that the goal is a highly accurate prediction of true breeding value for MRB, results of this work point to the need to 1) continue progeny testing, and 2) continue increasing the genetic correlation between the MBV and MRB.

Evidence for parent-of-origin effects on genetic variability of beef traits1

Neugebauer, N., Rader, I., Schild, H. J., Zimmer, D., Reinsch, N. — Wed, 27 Jan 2010 16:51:48 PST

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 are different. For genetic evaluation genomic imprinting can be accounted for by incorporating 2 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 analyzed with respect to the relative importance of the genetic imprinting variance. Besides slaughter weight, net daily BW gain, and killing out percentage, there were 22 other traits describing the carcass composition. The latter traits were evaluated by automatic video-imaging devices and were composed of 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 10 traits, with estimated proportions between 8 and 25% of the total additive genetic variance. For 6 of these traits, the maternal contribution to the imprinting variance was larger than the paternal, whereas 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 automatic video-imaging-recorded carcass traits ranged between 20 and 30%.

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

Wed, 27 Jan 2010 16:51:48 PST

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 Kaposvár University. Pannon White (PW) and maternal line (M) does were inseminated with the sperm of PW, M, large body line (LB), terminal line of Hycole hybrid (H), or colored line (CL) bucks. The mature body size of the M, PW, and CL genotypes was medium. The mature body size of the LB and H genotypes was large. Only PW and LB 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 BW gain (5.7%, P < 0.001) and G:F (6.2%, P < 0.001) of the progeny of PW does were better than those of the progeny of the M does. The weight of the chilled carcass and body parts was greater for the progeny of the PW does (P < 0.001). The ratio of the hind part compared with the reference carcass was greater in the PW group (P < 0.001); however, the ratio of the fore part was greater in the M group (P < 0.05). Examining the effect of the genotype of the sires, the BW and daily BW gain were greater in groups H and LB, whereas the progeny of M and CL sires were inferior (P < 0.05). Body weights at 11 wk of age were H: 2,918 g, LB: 2,793 g, PW: 2,678 g, CL: 2,636 g, and M: 2,585 g (P < 0.001). Similar differences were found for daily feed intake (P < 0.05). The G:F differed (P < 0.05) significantly between groups H and CL. The weights of the chilled carcass and of the body parts were the greatest for the progeny of the H sires, and the smallest in the M group. The differences between the dressing out percentages of the groups were not significant. The ratio of the fore part was greater (P < 0.05) in groups LB, H, and CL, 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 PW and least in LB and CL groups (P < 0.05). It was concluded that the production of growing rabbits was affected by the adult BW of their sires, but the carcass traits were influenced by their own adult BW and by the CT-based selection.

Genomic prediction of simulated multibreed and purebred performance using observed fifty thousand single nucleotide polymorphism genotypes

Kizilkaya, K., Fernando, R. L., Garrick, D. J. — Wed, 27 Jan 2010 16:51:48 PST

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 composed 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 greater average levels of LD in PB than in MB populations. Improved across breed prediction of genomic merit will require panels with more than 50,000 markers.

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. — Wed, 27 Jan 2010 16:51:48 PST

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.

Molecular cloning and characterization of porcine calcineurin-{alpha} subunit expression in skeletal muscle

Wed, 27 Jan 2010 16:51:49 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 transcription-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 AA 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 LM and soleus muscle 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 reduced abundance of CaN-A. Further studies are required to understand the functions of CaN-A isoform in skeletal muscle.

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

Peres, A. M., Dias, L. G., Joy, M., Teixeira, A. — Wed, 27 Jan 2010 16:51:49 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 the third sternebra). Moreover, both multiple models showed better results compared with those obtained with multiple linear regression models proposed in previous work.

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. — Wed, 27 Jan 2010 16:51:49 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 variables 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 after 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 decreased chill indices at birth, singleton litter status, greater presuckling rectal temperature, increased ewe prelambing plasma ghrelin concentration, female sex, heavier birth weight, and decreased lamb presuckling plasma glucose concentration. 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. Presuckling glucose concentrations were greater in singletons and lambs born to ewes of greater BCS at d 95 of gestation, and lambs of heavier birth weight, but were also associated with decreased rectal temperatures. This might reflect a delay in glucose utilization during the adjustment from a fetal metabolic rate to a rate appropriate for cold external environments. Singleton lambs exhibited decreased presuckling 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 elevated plasma glucose and leptin concentrations before lambing and was positively related to ewe BW at d 95 of gestation and to length of gestation. Greater presuckling plasma ghrelin and leptin concentrations were measured for shorter gestation lengths. Neonate presuckling 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 of 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.

Differential expression of liver proteins in Chianina and Holstein young bulls

Miarelli, M., Signorelli, F. — Wed, 27 Jan 2010 16:51:49 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 analyses were 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 analyzed through matrix-assisted laser desorption ionization mass spectrometry-time of flight (MALDI-TOF MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). A search against protein sequences in the National Center for Biotechnology Information databases indicated that the differentially expressed proteins correspond to liver-specific enzymes, with a major role in the metabolism of fatty acids, carbohydrates, AA, and the urea cycle.

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

Yates, D. T., Ross, T. T., Hallford, D. M., Yates, L. J., Wesley, R. L. — Wed, 27 Jan 2010 16:51:49 PST

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, intravenously) 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 by RIA. Although ewes responded to 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). The 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 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. — Wed, 27 Jan 2010 16:51:49 PST

Two experiments with finishing pigs were conducted to evaluate the effects of fluctuating dietary CP levels and ractopamine on performance and carcass traits. In Exp. 1, a total of 408 finishing pigs (mixed sex) were assigned to 1 of 4 protein regimens. Average initial and final BW 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. From 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) from wk 2 to 5. Overall (wk 0 to 5), BW gain, G:F, loin depth, percentage of lean, and dressing percentage were improved (P < 0.05) in pigs on regimens 3 and 4 compared with 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). Experiment 2 involved 172 finishing pigs (mixed sex) in 2 protein regimens. Average initial and final BW were 91 and 136 kg, respectively. The diets consisted of 1) a control (16% CP from d 0 to 14, 18% CP + 4.95 mg of ractopamine/kg from d 14 to 24, and 18% CP + 9.9 mg of 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 of ractopamine/kg from d 14 to 24, and 20.33% CP + 9.9 mg of ractopamine/kg from d 24 to 35. From d 0 to 14, pigs fed the low CP diet (12.5% CP) had reduced (P < 0.05) BW gain and G:F compared with those fed the control diet (16% CP). In contrast, from d 14 to 35, pigs on the low-high regimen had improved (P < 0.08) BW gain and G:F compared with pigs on the control regimen. Despite the wide dietary CP fluctuations for pigs in Exp. 2, performance and carcass traits were similar for both regimens over the 35-d test period. These data indicate that pigs fed deficient levels of CP and Lys for 14 d, followed by increased levels of CP and Lys 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.

Reduced feed intake of lactating primiparous sows is associated with increased insulin resistance during the peripartum 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. — Wed, 27 Jan 2010 16:51:49 PST

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 collected 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 of BW (glucose tolerance test), and during an euglycemic hyperinsulinemic clamp with an infusion rate of 100 ng of insulin·kg of BW^–1·min^–1. Both tests were performed at 4 stages 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 less 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 less 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. This result indicates that the interest in a Trp supplementation during the peripartum period can be questioned. Irrespective of the dietary treatment, the reasons why sows with similar rearing conditions develop different rates of insulin resistance during pregnancy remain to be elucidated.

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. — Wed, 27 Jan 2010 16:51:49 PST

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. Three 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. Tissue and milk samples from the sows were analyzed as a 2 x 3 x 4 factorial arrangement of treatments 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 arrangement of treatments 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 kilograms of 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 there were increases (P < 0.05) in Cu and Zn when the IND + Ca:P diet was fed compared with 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 was increased when organic Se was fed (P < 0.05) and when the micromineral level was 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, whereas 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.

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

Strathe, A. B., Danfaer, A., Sorensen, H., Kebreab, E. — Wed, 27 Jan 2010 16:51:49 PST

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 one that considers nonlinear repeated measures. Data were collected from an experiment with 40 pigs maintained from birth to maturity and their BW measured weekly or every 2 wk 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., sex, 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 sexes (barrows, boars, and gilts). It was estimated that the maximum growth rate occurs at 117, 134, and 96 kg of BW for barrows, boars, and gilts, respectively. Hence, the gilts reached their maximum growth rate at an earlier stage in life compared with boars. Mature size of pigs varied systematically with sex and was estimated to be 466, 537, and 382 kg of 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.

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

Calamari, L., Abeni, F., Bertin, G. — Wed, 27 Jan 2010 16:51:49 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 of Se/kg of 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 of total Se/kg of DM, respectively), and 1 positive control provided by sodium selenite (SS03 containing 0.3 mg of total Se/kg of 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 less in SY03 than SS03 horses (P < 0.05), and were less 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.

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. — Wed, 27 Jan 2010 16:51:49 PST

Most pulse (nonoilseed legume) seed flours can be fractionated rapidly and economically 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 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 with 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 ± 2.3 kg of 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 was 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 for 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 for 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, respectively, than starch concentrates. 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 indicated 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.

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. — Wed, 27 Jan 2010 16:51:49 PST

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 greater 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 SPC, respectively, in diets for young pigs.

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

Yang, W. Z., Ametaj, B. N., Benchaar, C., Beauchemin, K. A. — Wed, 27 Jan 2010 16:51:49 PST

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 of CIN (low), 800 mg/d of CIN (medium), and 1,600 mg/d of 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 with 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 greater ruminal digestion of OM. However, feed intake and ruminal digestion of feeds were adversely affected when a high dose of CIN was used.

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

Connors, M. T., Poppi, D. P., Cant, J. P. — Wed, 27 Jan 2010 16:51:49 PST

Initiation of mRNA translation and elongation of the polypeptide chain are 2 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 AA 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 AA supply, 24 ewe lambs of 25.9 ± 2.5 kg of 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 intravenous (i.v.) saline infusion as a control, i.v. infusion of 6 essential AA (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 of 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 of 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 the basal diet alone or the basal diet plus 6 AA. 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 fractional synthesis rate, translational efficiency, and concentrations of active ribosomes were consistently elevated. Ribosome transit time was not affected by long-term AA 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.

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

Walker, C. E., Drouillard, J. S. — Wed, 27 Jan 2010 16:51:49 PST

Four experiments were conducted to investigate the effects of ractopamine hydrochloride (RAC) on ruminal fermentation and proteolysis. In Exp. 1, in vitro gas and VFA production was measured in flasks incubated with 0, 0.226, 2.26, 22.6, and 226.0 mg of RAC/L of buffered ruminal fluid. Ractopamine hydrochloride 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 of RAC/L of 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 were measured in tubes treated with 0 or 2.26 mg of RAC/L of 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 ammonia and AA concentrations with RAC (P < 0.001). Experiment 4 used 16 ruminally fistulated Holstein steers in a 2 x 2 x 2 factorial arrangement of treatments. Factors consisted of grain processing method (steam-flaked or dry-rolled corn), concentration of dried distillers grains (DG) with solubles (0 or 25% DG, DM basis), and concentration of RAC (0 or 200 mg/d). Ruminal ammonia concentrations were less when RAC was fed in combination with dry-rolled corn, but not when RAC was fed in conjunction with steam-flaked corn (grain processing x RAC, P < 0.01). Addition of RAC, steam-flaked corn, and DG all resulted in reduced ruminal ammonia 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 ammonia and AA concentrations 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.

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

Wed, 27 Jan 2010 16:51:49 PST

To determine the effect of metabolic acidosis on expression of l-Gln, l-Glu, and l-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 reverse transcription-PCR and immunoblot analyses in homogenates of kidney, skeletal muscle, and liver of growing lambs fed a common diet supplemented with canola meal (control; n = 5) or HCl-treated canola meal (acidosis; n = 5). Acidotic sheep had a 790% greater (P = 0.050) expression of renal Na⁺-coupled neutral AA transporter 3 mRNA and a decreased expression of renal glutamine synthetase mRNA (47% reduction, P = 0.037) and protein (57% reduction, P = 0.015) than control sheep. No change in renal cytosolic phosphoenolpyruvate carboxykinase (protein and mRNA), glutaminase (mRNA), or l-Glu dehydrogenase (protein) was found. In skeletal muscle, acidotic sheep had 101% more (P = 0.026) aspartate transaminase protein than did control sheep, whereas no change in the content of 3 Na⁺-coupled neutral AA transporters (mRNA) or 2 high-affinity l-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 l-Asp and l-Glu by skeletal muscle, and l-Gln absorption by kidneys, but no change in hepatic expression of l-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 increased plasma lactate-induced metabolic acidosis commonly observed in ruminants fed a highly fermentable grain diet.

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. — Wed, 27 Jan 2010 16:51:49 PST

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 RDP supplement provided daily (RDP-D), 2) the high RDP supplement provided on alternate days (RDP-A), 3) a high RUP supplement provided on alternate days (RUP-A), or 4) a 50:50 mixture of the RDP and RUP supplements, provided on alternate days (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 less (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 with 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 less (P < 0.001) ruminal ammonia concentrations compared with RDP-D lambs, with RUP-A lambs exhibiting the least 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 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. — Wed, 27 Jan 2010 16:51:49 PST

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 RDP supplement provided daily (RDP-D), 2) the high RDP supplement provided on alternate days (RDP-A), 3) a high RUP provided on alternate days (RUP-A), or 4) a 50:50 mixture of the RDP and RUP supplements provided on alternate days. 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 (P ≥ 0.15) by treatment. Neither protein degradability nor supplementation frequency had an effect (P ≥ 0.52) on N retention. In Exp. 2, 15 lambs (34 ± 4 kg initial BW) fitted with indwelling catheters in a hepatic vein, the hepatic portal vein, a mesenteric vein, and a mesenteric artery 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 AA as RUP may provide a delay in ureagenesis, thus altering the timing of N recycling.

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

Relling, A. E., Pate, J. L., Reynolds, C. K., Loerch, S. C. — Wed, 27 Jan 2010 16:51:49 PST

The objectives of the present study were 1) to evaluate the effects of supplemental fat and ME intake on plasma concentrations of glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), glucose-dependent insulinotropic polypeptide, ghrelin, and oxyntomodulin; and 2) to determine the association of these peptides with DMI and the hypothalamic concentration of mRNA for the following neuropeptides: neuropeptide Y (NPY), agouti-related peptide (AgRP), and proopiomelanocortin (POMC). In 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 per day) or offered diets ad libitum (n = 16) 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, glucose-dependent insulinotropic polypeptide, oxyntomodulin, 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 concentrations of NPY, AgRP, and POMC mRNA. Offering feed ad libitum (resulting in greater ME intake) increased plasma insulin and NEFA concentrations (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 concentrations (P < 0.05 and 0.01, respectively) and tended to increase hypothalamic mRNA concentrations for NPY and AgRP (P = 0.07 and 0.11, respectively). Plasma GLP-1 and CCK concentrations increased in wethers offered feed ad libitum compared with restricted-fed wethers, 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). The prefeeding plasma ghrelin concentration was greater in restricted-fed wethers compared with those offered feed ad libitum, but the concentrations were 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.

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. — Wed, 27 Jan 2010 16:51:49 PST

The objective of this study was to investigate the effects of chitosan (CHI) on ruminal and cecal fermentation and on apparent digestibility in sheep. In a first trial, 4 ruminally fistulated sheep fed an alfalfa hay and concentrate diet formulated to meet 1.2 times their maintenance energy requirements were assigned to 2 treatments [no-additive control (CTR), or 136 mg/kg of BW of CHI] for 19 d in a 2 x 2 crossover design. Samples of ruminal fluid and feces were taken for VFA and 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 on fermentation variables for starch, cellulose, and the same diet fed to the animals were calculated. In a second trial, 4 sheep fed the alfalfa hay and concentrate diet were assigned to 2 treatments (CTR and CHI), as for the first trial, but this time for 14 d in a 2 x 2 crossover design. Apparent digestibility was studied. In the first trial, in terms of ruminal fermentation, CHI did not affect (P = 0.12) total VFA concentration or acetate proportion, but increased propionate proportion (P = 0.004) and propionate-to-acetate ratio (C3:C2; P = 0.007) and decreased branched-chain VFA (BCVFA) proportion (P = 0.003) and NH₃-N concentration (P = 0.045). In feces, CHI decreased total VFA concentration (P = 0.01) and acetate (P = 0.045) and butyrate (P = 0.025) proportions, and increased propionate (P = 0.04), valerate (P = 0.01), and BCVFA (P = 0.032) proportions and C3:C2 ratio (P = 0.045). In batch cultures, when starch was used as substrate, CHI decreased acetate proportion (P = 0.016) and methane production (P = 0.03) and increased propionate and valerate proportions and C3:C2 ratio (P < 0.001). When cellulose was used as substrate, CHI decreased in vitro OM digestibility (P = 0.033), total VFA concentration, propionate proportion (P < 0.001), C3:C2 ratio (P = 0.006), methane production (P < 0.001), NH₃-N concentration (P = 0.019), and gas production rate (P = 0.002), and increased butyrate (P = 0.029) and BCVFA (P = 0.004) proportions and pH (P < 0.001). When the alfalfa hay and concentrate diet was used as substrate, CHI decreased butyrate (P < 0.001) and BCVFA (P = 0.008) proportions, methane (P = 0.005) and asymptotic gas production (P = 0.02), and gas production rate (P = 0.05). In the second trial, CHI decreased NDF apparent digestibility (P = 0.09). In conclusion, CHI shifted ruminal fermentation toward energetically more efficient routes, without reducing OM apparent digestibility.

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

Wed, 27 Jan 2010 16:51:49 PST

The objective of this study was to compare the fatty acid (FA) composition of intramuscular fat from the LM of 3 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 before slaughter in one year and 157 d in the next year. Longissimus muscle samples were collected from each carcass between the 10th and 13th ribs, trimmed of external fat, frozen in liquid nitrogen, homogenized, and used for fat extraction, using a modified Folch procedure. Extracted fat was analyzed for FA by 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 a saturation index (ratio of total SFA to total unsaturated FA). Crude fat determination revealed that LM from AN purebred cattle had the greatest amount of intramuscular fat (7.08%; P = 0.001). Although intramuscular fat of LM from RM contained a reduced percentage of total SFA (P = 0.002) compared with AN, it had the greatest percentage of total PUFA (P < 0.001 and P = 0.020). The percentages of total MUFA were similar among the 3 breeds (P = 0.675). The gravimetric calculation, a measure of actual FA concentration, showed significantly greater concentrations of SFA (26.67 mg/g), MUFA (26.50 mg/g), and PUFA (2.37 mg/g) in LM from AN cattle, as compared with LM from BR and RM cattle (P < 0.001). Interestingly, BR purebreds had the least PUFA concentration (1.49 mg/g; P ≤ 0.001) in the LM, although their intramuscular fat content was similar to that of RM (P = 0.924). Regardless of breed, the MUFA proportion was always the greatest (47.58%; P ≤ 0.005), whereas PUFA was the least contributor to FA composition (1.49 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 FA (P < 0.001). These results suggested a genetic variation in FA synthesis and deposition among breeds that influenced both marbling and its composition.

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. — Wed, 27 Jan 2010 16:51:49 PST

The accuracy of 3 optical probes (HGP4 Hennessey Grading Probe, Destron-Feering PG-100 probe, and Giraldo OPTO-Electronic PG-200 probe) to predict the carcass percentage of 5 alternative measures of carcass composition (fat-tissue-free lean, lipid-free soft tissue, lipid-free lean, total fat tissue, and soft tissue lipid) was evaluated on 203 barrows and gilts of 7 genetic populations. The optical probe backfat depths were more closely 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), total fat tissue percentage (r = 0.84 to 0.88), and soft tissue lipid percentage (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 total fat tissue percentage (r = –0.16 to –0.26). Fat-free lean percentage was predicted with residual SD (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 for the optical probe equations ranged from 2.1 to 2.4% for lipid-free soft tissue percentage and from 2.0 to 2.3% for lipid-free lean percentage. The RSD for the optical probe equations ranged from 2.9 to 3.3% for total fat tissue percentage and 2.5 to 2.8% for soft tissue lipid percentage. Quadratic and cross-product variables of optical probe fat depth, LM depth, and carcass weight were significant (P < 0.05) and reduced the RSD of the equations. Optical probe backfat and LM measurements can be used to predict alternative measures of carcass composition. The predicted relationships in fat-free lean percentage to backfat depth were nearly identical for each optical probe.

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., Kang, H. J., Ahn, D. U. — Wed, 27 Jan 2010 16:51:49 PST

Sausages with different fat contents (16 or 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 substance values of sausages were not affected by fat content but were increased after irradiation (5 kGy). Storage for 60 d increased the 2-thiobarbituric acid-reactive substance values of nonirradiated sausages (P < 0.05) but had no effect on irradiated sausages. The numbers of volatile compounds and the amounts of total volatiles were increased by irradiation in both the 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 it disappeared after 60 d of storage. Pentane and 1-heptene were detected only in irradiated samples after 60 d of storage. Low-fat sausages had greater L* values, but had lesser a* and b* values than high-fat sausages. Irradiation and storage had little effect on either the exterior or interior color (L*, a*, and b* values) of sausages. Fat content had no effect on the sensory variables of sausages, regardless of irradiation and storage. However, irradiated sausages had significantly stronger off-odors and off-flavors than nonirradiated sausages regardless of fat content (P < 0.05). This indicated that fat content in sausages had a minimal effect on the quality of irradiated sausages during storage.

Pain mitigation after band castration of beef calves and its effects on performance, behavior, Escherichia coli, and salivary cortisol

Wed, 27 Jan 2010 16:51:49 PST

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 Escherichia 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 pain medication (M; xylazine epidural and intravenous flunixin meglumine) or saline (NM) solutions at 0.5 h before castration. Feed intake, ADG, and feeding behavior were measured over a 3-wk period before (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 less in B compared with C (P < 0.001), but feed intake was less during wk 4 only (P = 0.01). On average, M had less intake (P = 0.02) and eating rate (P = 0.04) than NM calves. The BM had less fecal E. coli counts than CM (P = 0.05) and castrated and nonmedicated calves (P = 0.08). Salivary cortisol was less in BM compared with 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 noncastrated and non-pain-medicated group compared with the rest, except for reduced meal frequency, indicating that pain medication and castration both 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.

Trait selection and welfare of genetically engineered animals in agriculture

Greger, M. — Wed, 27 Jan 2010 16:51:49 PST

The release of the Final Guidance from the US 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 may be undermined.