HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) All Versions of this Article: jas.2007-0383v1 86/8/1868    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Banta, J. P. Articles by Wettemann, R. P. Search for Related Content PubMed PubMed Citation Articles by Banta, J. P. Articles by Wettemann, R. P.

Whole soybean supplementation and cow age class: Effects on intake, digestion, performance, and reproduction of beef cows¹

J. P. Banta^*,2, D. L. Lalman, C. R. Krehbiel and R. P. Wettemann

^* Department of Animal Science, The Texas A&M University System, Overton 75684 Department of Animal Science, Oklahoma State University, Stillwater 74078

	Abstract

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Two experiments were conducted to determine the effects of whole soybean supplementation on intake, digestion, and performance of beef cows of varying age. Treatments were arranged in a 2 x 3 factorial with 2 supplements and 3 age classes of cows (2-yr-old, 3-yr-old, and mature cows). Supplements (DM basis) included 1) 1.36 kg/d of whole raw soybeans, and 2) 1.56 kg/d of a soybean meal/hulls supplement. Supplements were formulated to provide similar amounts of protein and energy, but a greater fat content with the whole soybeans. Supplements were individually fed on Monday, Tuesday, Thursday, and Saturday mornings. During the treatment period, cows had free choice access to bermudagrass hay [Cynodon dactylon (L.) Pers.; 8.4% CP; 72% NDF; DM basis]. In Exp. 1, 166 spring-calving Angus and Angus x Hereford crossbred beef cows were individually fed supplements for an average of 80 d during mid to late gestation. During the first 50 d of supplementation, cows fed soybean meal/hulls gained more BW (10 kg; P < 0.001) and body condition (0.18 BCS units; P = 0.004) than cows fed whole soybeans. However, BW change (P = 0.87) and BCS change (P = 0.25) during the 296-d experiment were not different between supplements. Although calves from cows fed soybean meal/hulls were 2 kg heavier at birth, there was no difference in calf BW at weaning between supplements. Additionally, first service conception rate (68%; P = 0.24) and pregnancy rate (73%; P = 0.21) were not different between supplements. In Exp. 2, 24 cows from Exp. 1 were used to determine the effect of supplement composition on forage intake and digestion; cows remained on the same supplements, hay, and feeding schedule as Exp. 1. Crude fat digestibility was the only intake or digestibility measurement influenced by supplement composition; fat digestibility was higher for cows fed whole soybeans compared with cows fed the soybean meal/hulls supplement (58.1 vs. 48.8%). Hay intake and DMI averaged 1.63 and 1.92% of BW daily, respectively. Dry matter, NDF, and CP digestibility averaged 54.1, 55.1, and 63.2%, respectively. Compared with supplementation with soybean meal/ hulls, whole soybean supplementation during mid to late gestation resulted in reduced BW weight gain during supplementation, inconsistent effects on reproduction, no effect on calf weaning weight, and no effect on forage intake or digestion.

Key Words: beef cow • prepartum • whole soybean

	INTRODUCTION

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Reproduction is one of the most crucial factors in determining profitability of a beef cow/calf enterprise. Thus, nutrition and management strategies to optimize or maximize reproductive efficiency are continually being researched. One nutrition strategy that has received considerable attention in recent years is the potential nutraceutical effect of lipid supplementation. Williams and Stanko (2000) defined a nutraceutical as a feedstuff or feed additive having physiological effects outside of its generally accepted role as a nutrient source. Increased lipid intake may improve reproductive efficiency through increased functional capacity of the ovary or alterations in PGF₂ synthesis by the uterus or both (Williams and Stanko, 2000).

Effects of oilseed and commercial fat supplements on reproduction are inconsistent and have increased (Lammoglia et al., 1997; DeFries et al., 1998; Bellows et al., 2001), not influenced (Lammoglia et al., 2000; Grings et al., 2001; Alexander et al., 2002; Funston et al., 2002; Geary et al., 2002), or numerically decreased (Bellows et al., 2001) reproductive efficiency of beef cows. Of the oilseeds and commercial fat supplements that have been evaluated to this point, soybeans show the most consistent results; numeric (Steele et al., 2007; Howlett et al., 2003) as well as statistically significant (Bellows et al., 2001; Graham et al., 2001) increases in reproductive efficiency have been reported. Based on the available literature, we hypothesized that moderately increased lipid intake from whole soybeans during mid to late gestation would improve reproduction of beef cows without negatively impacting forage utilization and thus cow or calf weight gain. The objectives of these experiments were to determine the effects of supplementing whole raw soybeans to beef cows of varying age on 1) reproduction and performance of beef cows as well as performance of their progeny; and 2) forage intake and digestion.

	MATERIALS AND METHODS

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Experiment 1

This experiment was conducted at the Range Cow Research Center, North Range Unit located approximately 16 km west of Stillwater, OK, in accordance with an approved Oklahoma State University Animal Care and Use Committee protocol.

Treatments were arranged in a 2 x 3 factorial with 2 supplements and 3 age classes of cows (2-yr-old, n = 50; 3-yr-old, n = 54; and mature cows, n = 48). During the winter of 2003 and 2004, 166 spring-calving Angus and Angus x Hereford crossbred beef cows were assigned to 1 of 6 different treatment combinations in a completely randomized design. Cows were assigned to treatments so that initial BW and BCS would be similar within age class. Additionally, cows were assigned to supplements so that cow age class and age of cow within the mature age class (average = 7.2 yr; range = 5 to 12 yr) would be similar.

Supplements (DM basis) included 1) 1.36 kg/d of whole raw soybeans (39% CP, 21.4% ether extract), and 2) 1.56 kg/d of a soybean meal/hulls supplement (54.4% soybean meal, 45.6% soybean hulls). Supplements were formulated to provide similar amounts of protein and energy; actual nutrient content is reported in Table 1. Supplements were individually fed on Monday, Tuesday, Thursday, and Saturday mornings. The amount of supplement fed on each of these 4 d was determined by calculating the amount of supplement needed weekly (daily supplement amount x 7 d) and dividing that amount by 4 (e.g., cows receiving whole soybeans were fed 2.38 kg/feeding, DM basis).

Beginning on April 6, 2004, all cows were managed as a single group and were given access to either bermudagrass pasture or tall-grass prairie pasture and a mineral supplement (42.1% NaCl; 9.5% Ca; 8.3% P; 0.3% Mg; 1,039 mg/kg Cu; 12 mg/kg Se; 3,110 mg/kg Zn; DM basis).

Individual cow BW and BCS was determined at the start of supplementation (12/22/03), after the first 50 d of supplementation before any cows had calved (2/10/04), at the onset of breeding (5/4/04), and at weaning (10/13/04). Cows were weighed 16 h after with-drawal from feed and water. Body condition scores (1 = emaciated, 9 = obese) were determined by the same 2 independent evaluators throughout the experiment.

Before the start of this experiment, all cows were bred to calve over a 66-d period from February 18 to April 24, 2004 (assuming a 282-d gestation). The 2-yr-old cows were bred to start calving at the same time as the 3-yr-old and mature cows. The calving season lasted for 69 d from February 12 to April 21, 2004 (average calving date: March 12, 2004). Birth weight of each calf was determined within 24 h of birth, and all male calves were castrated at this time. Additionally, calf weights were determined on June 14 and October 12, 2004, without restriction from feed, milk, or water. Calves were weaned on October 12, 2004.

The percentage of cows exhibiting luteal activity at the start of the breeding season was determined by quantifying progesterone concentration (Vizcarra et al., 1997) in plasma samples obtained via tail venipuncture 7 d before and again on the first day of the breeding season. Cows with 1 or more plasma samples containing 0.5 ng/mL progesterone were considered to have luteal activity (Webb et al., 2001; White et al., 2002; Ciccioli et al., 2003; interassay CV = 30.2%; intraassay CV = 31.4%). Cows were artificially inseminated from May 4 through June 14, 2004, followed by natural mating from June 14 through July 6, which resulted in a 63-d breeding season. Cows were observed each morning and evening for 1 h to detect standing estrus; all cows exhibiting standing estrus were artificially inseminated approximately 12 h after estrus observation. First service conception rate was determined by transrectal ultrasonography approximately 30 d after AI; cows were palpated per rectum at weaning to determine pregnancy rate.

Statistical Analysis. Cow was considered to be the experimental unit because supplements were individually fed to each cow. All continuous data were analyzed using MIXED MODEL procedures (SAS Inst. Inc., Cary, NC) and the Satterthwaite approximation for df. The models for cow performance included supplement, cow age class, and the supplement x cow age class interaction as fixed effects. The models for calf performance included supplement, cow age class, calf sex, supplement x cow age class, supplement x calf sex, cow age class x calf sex, and supplement x cow age class x calf sex as fixed effects; calf age was included as a covariate for the June 14 and weaning weight models. The models for days from calving to the start of the breeding season and days from calving to first AI date included supplement, cow age class, and the supplement x cow age class interaction as fixed effects. When the P-value for the F-statistic was 0.05, least squares means were separated using the LSD procedure of SAS ( = 0.05). Least squares means are reported in all tables; overall means in the text represent the simple average of the least squares means, except for percentage of cows exhibiting luteal activity, pregnancy rate, and first service conception rate which are raw means.

Categorical modeling procedures (PROC CATMOD) were used to test reproductive data for interactions between supplement and cow age class. If no interactions were detected, contingency tables were developed for proportional differences among main effects for percentage of cows exhibiting luteal activity, first service conception rate, and pregnancy rate. These main effects were analyzed using FREQ procedures of SAS and a ² test. The SE for proportion data was calculated as: P(1 - P)/n where P = proportion of the variable in question (M. Payton, Department of Statistics, Oklahoma State University, Stillwater, personal communication).

For various reasons (failure to calve, n = 2; calf death, n = 7; injury, n = 2; miscellaneous, n = 3) data from 14 cows and their calves were removed from the experiment. No relationship was apparent between any of these factors and mid- to late-gestation supplement composition. Consequently, only the data from the 152 cows that weaned a calf in October were included in the statistical analysis.

Experiment 2

This experiment was also conducted at the Range Cow Research Center, North Range Unit, in accordance with an approved Oklahoma State University Animal Care and Use Committee protocol.

During mid to late gestation, 24 spring-calving beef cows from Exp. 1 were used to determine the effects of supplement composition and cow age class on hay intake and digestion. Based on expected calving date and treatment from Exp. 1, cows were assigned to 1 of 2 collection periods in a randomized complete block design. Two cows from each treatment combination were represented in each period resulting in a total of 4 cows from each treatment combination. Cows were given ad libitum access to the same bermudagrass hay fed in Exp. 1 and also maintained on the same feeding schedule as Exp. 1 (Monday, Tuesday, Thursday, and Saturday mornings). Cows were maintained in individual outdoor 3.7- x 9.1-m pens so that they would be exposed to the same environmental conditions as their herd mates in Exp. 1. Experiments 1 and 2 were conducted concurrently during the winter of 2003 to 2004.

Each 16-d period consisted of 7 d of adaptation to the pens and hay feeders, and 9 d of data collection. Hay in-take was measured from d 8 through 14 and fecal grab samples were collected twice daily at 0800 and 1600 h from d 10 through 16 to predict fecal output from acid detergent insoluble ash concentration. Sub-samples of supplements, hay, and orts were dried at 100°C to determine DM. Hay, ort, and fecal samples were dried at 50°C and ground in a Wiley mill (Model–4, Thomas Scientific, Swedesboro, NJ) to pass a 2-mm screen before analysis. The supplements were dried at 50°C and the soybean meal/hulls supplement was ground in the Wiley mill; however, the whole soybeans were ground in a household coffee and spice mill (Regal Ware Inc., Kewaskum, WI) to pass a 2-mm sieve. After grinding, supplement and hay samples were composited within period; ort and fecal samples were composited by cow. All composite samples were analyzed for NDF, ADF, CP, crude fat, and acid detergent insoluble ash. Neutral detergent fiber and ADF content were determined using an ANKOM Fiber Analyzer (ANKOM Technology, 2005a,b). Crude protein was determined using a Leco NS-2000 Nitrogen Analyzer (Leco Corporation, St. Joseph, MI). Acid detergent insoluble ash was determined as the residue after complete combustion of the ADF residue (Van Soest et al., 1991). Ether extraction (AOAC, 2005) was used to determine crude fat concentration.

Apparent DM, OM, CP, and crude fat digestibility as well as NDF and ADF digestibility were calculated for each cow. Additionally, digestible DMI (DMI, kg/100 kg of BW x DM digestibility) and digestible OM intake were calculated for each cow.

Statistical Analysis. Intake and digestibility measurements were analyzed as a randomized complete block design using MIXED MODEL procedures of SAS and the Satterthwaite approximation for df. The models included supplement, cow age class, and supplement x cow age class as fixed effects, period as a random effect, and days from last measured hay intake to calving as a covariate. When the P-value for the F-statistic was 0.05, least squares means were separated using the LSD procedure of SAS ( = 0.05). Least squares means are reported in all tables and overall means in the text represent the simple average of the least squares means. One cow was removed from the digestion experiment because she aborted sometime after the start of Exp. 1 and before the start of Exp. 2. Another cow was also removed from Exp. 2 because she calved before the end of Exp. 2. Consequently, only 22 cows were used in the statistical analysis.

	RESULTS

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Experiment 1

No supplement x cow age class interactions (P = 0.06 to 0.96) were observed for cow BW, cow BCS, or calf performance data. Additionally, no interactions were observed for first service conception rate (P = 0.36) or pregnancy rate (P = 0.12). Consequently, only main effect means are reported for these data. A supplement x cow age class interaction was observed for percentage of cows exhibiting luteal activity at the start of the breeding season. In addition to the interaction means reported in the text, main effect means for percentage of cows exhibiting luteal activity at the start of the breeding season are reported in Tables 4 and 7.

Cow BW and BCS. Length of the supplementation period was not different between supplements (80 d; Table 2). During the first 50 d of supplementation, cows fed soy-bean meal/hulls gained 10 kg more BW than cows fed whole soybeans (Table 2). However, supplement composition did not influence BW change during any of the subsequent weigh periods (Table 2). Additionally, final BW at weaning and BW change over the 296-d experiment (–19 kg; Table 2) were not different between treatments. Body condition score change followed the same pattern as BW change. During the first 50 d of treatment supplementation, cows fed soybean meal/hulls gained more body condition than cows fed whole soybeans (Table 2). However, BCS before calving (5.18; P = 0.16), at the start of the breeding season (4.86; P = 0.58), and final BCS at weaning (4.60; Table 2) were not different between supplements.

Main Effect of Cow Age Class

Some of the differences observed among the different age classes of cows may be due to genetic differences because sires of the mature cows were different than sires of the 2- and 3-yr-old cows. Additionally, the 2- and 3-yr-old cows are daughters of the mature cows, although sires are common among the 2- and 3-yr-old cows.

Cow BW and BCS. Length of the supplementation period was not different among cow age class (80 d; Table 5). During the first 50 d of treatment supplementation, mature cows gained 10 kg more BW than 3-yr-old cows and 19 kg more BW than the 2-yr-old cows. However, during the subsequent period from before calving to the start of the breeding season the mature cows lost 29 kg more BW than the 3-yr-old cows and 37 kg more BW than the 2-yr-old cows. During the 296-d experiment, the 3-yr-old cows lost the least BW and the mature cows lost the most BW (Table 5). Initial BCS was greatest for the 2-yr-old cows (5.49), intermediate for the mature cows (5.17), and least for the 3-yr-old cows (4.90; Table 5). During the supplementation period, a slight gain of body condition was observed for the 3-yr-old and mature cows and a slight loss of body condition was observed for the 2-yr-old cows (Table 5). However, during the subsequent periods all age groups lost body condition. During the entire experiment the 2-yr-old cows lost the most body condition and the 3-yr-old cows lost the least body condition. These losses resulted in no significant difference in BCS among the age classes at weaning (4.59; Table 5).

Experiment 2

No supplement x cow age class interactions (P = 0.10 to 0.69) were detected for any of the intake or digestibility measurements. Crude fat digestibility was greater for cows fed whole soybeans than for cows fed the soy-bean meal/hulls supplement (Table 8). Supplement did not have a significant influence on any of the other in-take or digestibility measurements (Table 8). Cow age class did not influence intake or digestibility measurements (Table 9). Hay intake and DMI averaged 1.63 and 1.92% of BW daily, respectively. Dry matter, NDF, and CP digestibility averaged 54.1, 55.1, and 63.2%, respectively. Digestible DMI averaged 1.03% of BW daily.

	DISCUSSION

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Cow BW, BCS, Intake, and Digestion

Soybean supplementation resulted in less cow weight and body condition gain during the experimental feeding period compared with the soybean meal/hulls supplement. In previous work conducted at our experiment station (Banta et al., 2006), cows fed a soybean hull-based supplement (2.0% dietary fat) gained 23 kg more BW than cows fed high-fat sunflower seeds (5.7% dietary fat) during late gestation. Similarly, cows fed a soybean hull/soybean meal-based supplement (1.8% diet DM fat) gained 18.7 kg more BW than cows fed processed, drought-damaged soybeans (3.8% dietary fat) during late gestation (Steele et al., 2007). In each of these experiments and in the current study, supplements were formulated to provide approximately equal protein and energy, and supplements were fed on an interval basis similar to the current experiment. Therefore, lesser weight gains of cows fed the oilseed-based supplements in each of these studies suggests that oilseed supplementation combined with an interval feeding strategy resulted in a reduction in voluntary forage intake, reduced forage (fiber) digestibility, or incomplete or inefficient use of supplemental energy.

Lesser BW gains of cattle fed lipid-fortified supplements are commonly attributed to a reduction in fiber digestibility when dietary lipid concentration exceeds 5% (Moore et al., 1986; Byers and Schelling, 1988; Jenkins, 1993) or when supplemental fat is included at 3% of DMI (Hess et al., 2008). Accordingly, we designed the whole soybean treatment to deliver a diet containing 3.8% fat on a DM basis (2.9% of DMI as supplemental fat) to minimize the potential of compromising forage intake and digestibility. It should be noted that dietary lipid intake on feeding days represented approximately 5.4% of diet DM. Therefore, one might anticipate that the interval feeding strategy would exacerbate any negative associative effect from whole soybeans. However, data from Table 8 confirm that neither forage intake nor digestibilities of dietary components were compromised with soybean supplementation compared with the low-fat soybean meal/hulls supplement.

Other scientists have reported no differences in weight gain among forage-fed cattle receiving lipid supplements or diets with added dietary fat. Lammoglia et al. (2000) reported no difference in weight gain of prepubertal heifers fed a low-fat diet (1.9% fat) or a high-fat safflower seed diet (4.4% fat). Additionally, Bottger et al. (2002) reported no difference in BW gain for primiparous cows fed a corn-soybean meal supplement (21.1 kg), high-linoleate-safflower seed (16.3 kg), or high-oleate safflower seed (32.6 kg) for 90 d postcalving.

Similar to our results, others have reported no differences in feed intake due to moderate levels of lipid supplementation. In a review of 18 experiments, Coppock and Wilks (1991) reported that whole cottonseed could be included at up to 25% of the diet without influencing DMI of dairy cows. Brokaw et al. (2001) reported that ruminal infusion of soybean oil did not influence forage or total OM intake of beef heifers grazing bromegrass pastures. Supplementation of crushed canola seed did not influence DMI (kg/d) of steers fed corn silage-based diets (Hussein et al., 1995).

In contrast to results in the present study, Howlett et al. (2003) reported that total tract NDF but not OM digestibility was significantly decreased for steers limit fed corn silage-based diets containing 15% whole cottonseed, 15% whole soybeans, or 25% whole soybeans compared with steers fed a control supplement. Dietary fatty acid concentration was 4.5, 5.5, 7.4, and 2.5% for the 15% whole cottonseed, 15% whole soybean, 25% whole soybean, and control diets, respectively. Scholljegerdes et al. (2004) observed a significant reduction in total tract OM and NDF digestibility for heifers limit fed bromegrass hay and high-linoleic or high-oleic cracked safflower seeds compared with heifers fed hay and a control supplement. However, it should be noted that the dietary fatty acid content of the control diet, linoleic safflower seed diet, and oleic safflower seed diet were 3.0, 7.2, and 7.4% (DM basis), respectively. These diets (Scholljegerdes et al., 2004) contained considerably more lipid than the diets in the present experiment, which contained 1.5 and 3.8% lipid for the soybean meal/hulls and whole soybean diets, respectively. Moore et al. (1986) reported that ADF, DM, and OM digestibilities were not different between diets with 0 or 2% added animal fat but were decreased with 4% added animal fat; chloroform-methanol lipid concentrations were 2.0, 4.4, and 6.8%, respectively, for the 0, 2, and 4% added fat diets. The lack of difference in ADF, DM, and OM digestibility between the diets with 2.0 and 4.4% lipid agrees with results from the present study.

One would expect oilseed supplementation to increase apparent lipid digestibility because of the high prevalence of fatty acids in the ether extract of oilseeds when compared with pigments and waxes present in forages (Byers and Schelling, 1988). Consequently, apparent fat digestibility increases with increasing supplemental lipid intake (Smith et al., 1981; Moore et al., 1986; Palmquist, 1994). Experiment 2 data was used to calculate the partial digestion coefficient within period for supplemental fat (Grummer, 1988) using the following equation:

Partial supplemental fat digestibility was 67.9% for period 1 and 66.5% for period 2, with a mean of 66.5%. Assumptions associated with this method are that endogenous lipid remains constant, and the digestibility of fatty acids in the basal diet remains constant when supplemental fat is fed (NRC, 2001). These values are substantially lower than the true digestibility value for vegetable oils (86%) reported by NRC (2001) using this method. Even though apparent fat digestibility increased (P < 0.001) with whole soybean supplementation, Palmquist (1991) reported that true digestibility of supplemental fat decreases linearly with increasing fat intake. Additionally, Kucuk et al. (2001) demonstrated a reduction in postruminal disappearance of fatty acids as forage level in the diet increased. It is unknown whether the level of fat supplementation from whole soybeans in our study was sufficient to depress true fat digestibility. However, the lower than expected partial digestibility data, combined with depressed cow weight gain, suggests that true fat digestibility may have been depressed to some extent.

Treatment period BW change increased as cow age increased. Similarly, treatment period BW change was greater for older age classes when BW change was expressed as a percentage of initial BW (4.3, 5.7, and 6.6% of BW for 2-yr-old, 3-yr-old, and mature cows, respectively). Cumulative BW loss during the 296-d was greater for 2-yr-old and mature cows compared with 3-yr-old cows (–4.3, –0.7, and –5.5% of initial BW for 2-yr-old, 3-yr-old, and mature cows, respectively).

Published reports of the effect of cow age class on intake and digestibility are limited. In agreement with results from our experiment, Johnson et al. (2003) reported no differences in forage intake (% of BW daily), apparent diet OM digestibility, or total digestible OM intake (% of BW daily) for primiparous cows compared with multiparous cows fed low-quality hay during late gestation. The results of the present study and those of Johnson et al. (2003) suggest that separate DMI prediction equations are not warranted for primiparous and multiparous cows.

Calf Performance

In previous studies at our facility, prepartum sun-flower seed supplementation did not influence calf birth or weaning weight (Banta et al., 2006). After a review of the literature, Hess et al. (2002) concluded that prepartum lipid supplementation did not influence calf birth or weaning weight. However, a 2-kg increase in birth weight was observed in the present study for cows fed soybean meal/hulls. This increase in birth weight, along with increased cow BW and body condition gain during the treatment period suggests that cows fed soybean meal/hulls were in a slightly greater positive energy balance than cows fed whole soybeans, even though supplement treatments were designed to deliver similar amounts of energy.

Increased birth and weaning BW of calves from multiparous dams compared with primiparous dams have previously been reported (Doornbos et al., 1984; Triplett et al., 1995). Additionally, observed differences in the present experiment among 2-yr-old, 3-yr-old, and mature cows are in line with parity adjustments for birth and weaning BW recommended by the Beef Improvement Federation (2002).

Cow Reproductive Performance.

In this experiment, whole soybean supplementation increased luteal activity in mature cows, with no impact on luteal activity of 2- or 3-yr-old cows. Increased luteal activity in mature cows did not result in improvements in final pregnancy rates or first service conception rates for soybean-fed cows, and there were no significant interactions for supplement source by cow age class for these variables. Previous research with soybean supplementation during mid to late gestation has resulted in similar inconsistent results. Steele et al. (2007) studied reproductive performance of cows fed a soybean meal/soybean hull supplement or drought-stressed soybeans. Luteal activity at the beginning of the breeding season was reduced when cows were fed whole soybeans, although there was no change in luteal activity when cows were fed processed soybeans compared with the control-fed cows. In 2 experiments, Bellows et al. (2001) found no change in luteal activity of primiparous cows fed processed oilseeds high in fat (safflower, soybean, or sunflower) compared with cows fed a barley/soybean meal supplement. Steele et al. (2007) reported no differences in final pregnancy rate, whereas Bellows et al. (2001) reported increased pregnancy rate due to oilseed supplementation in one experiment, but not in the second experiment. Banta et al. (2006) found no differences in luteal activity, pregnancy rate, or AI conception rate when cows were fed either high-linoleic acid sunflower seeds or a soybean hull-based supplement during mid to late-gestation. The lack of consistent results in these experiments suggests that positive nutraceutical effects on reproduction in the beef cow due to supplementation from soybeans and other oilseeds are at best unreliable.

Pregnancy rates were lower than expected in this experiment. The low pregnancy rate observed for the 2-yr-old cows may be related to lower than expected nutrient intake during mid and late gestation. Using the NRC (1996) computer model and predicted dietary and environmental variables, total DMI and body condition gain were predicted for each age class of cows before the experiment. Based on these predictions it was determined that the amount of supplements fed would be sufficient for all cows to gain a similar amount of body condition given their differences in maintenance and growth requirements (NRC, 1996). The computer predictions over estimated DMI for all age classes and thus the amount of body condition that they would gain. However, the over prediction in DMI was greater for the 2-yr-old cows (2.37 vs. 1.90% of BW daily) compared with the 3-yr-old (2.19 vs. 1.91% of BW daily) and mature cows (2.10 vs. 1.93% of BW daily). Given a limited breeding season (63 d) and the fact that the 2-yr-old cows were losing body condition before calving and at the start of the breeding season their low pregnancy rate is not surprising (Vargas et al., 1999; Whittier et al., 2005). The low pregnancy rate observed for the 2-yr-old cows reaffirms the need to manage primiparous and multiparous cows differently, as recently reviewed (Banta et al., 2005; Whittier et al., 2005). Spitzer et al. (1995) reported pregnancy rates of 56, 80, and 96% for primiparous cows with a BCS of 4, 5, or 6 at parturition, respectively. The review by Whittier et al. (2005) and the report of Spitzer et al. (1995) suggest that pregnancy rate of the 2-yr-old cows in the present study may have been improved if these heifers were in a body condition score of 6 or greater before calving compared with the observed BCS of 5.3.

Differences in the interval from calving to luteal activity due to age class are well established. Intervals from parturition to first ovulatory estrus are extended 1 to 5 wk for primiparous compared with multiparous cows (Wiltbank, 1970; Yavas and Walton, 2000). Increased interval from parturition to first ovulatory estrus for primiparous cows would be expected to result in a reduced percentage of primiparous cows exhibiting luteal activity at the beginning of the breeding season. Although the 2-yr-old cows in the present study had greater BCS before calving, a fewer number had exhibited luteal activity at the beginning of the breeding season as compared with the 3-yr-old and mature cows. Consequently, mean days from calving to first AI date were extended by 13 d for 2-yr-old compared with mature cows. Similarly, Doornbos et al. (1984) reported that 78% of primiparous cows were in estrus at the beginning of the breeding season as compared with 95% of multiparous cows.

Few data are available to determine whether parity influences conception rate independent of other factors. We observed no difference in first-service conception rate due to parity. In agreement with these results, DeJarnette et al. (2004) reported that parity did not influence conception rates to AI.

In conclusion, whole soybean supplementation was associated with a reduction in BW and body condition gain compared with a soybean meal/hulls-based supplement. This reduction in cow performance during the supplementation period could not be explained by reduced forage intake or OM digestibility. Although there was some indication that whole soybean supplementation resulted in more mature cows having luteal activity at the beginning of the breeding season, there was no similar effect in 2- and 3-yr-old cows. Moreover, whole soybean supplementation did not influence first service conception or pregnancy rate, regardless of age class. The 2-yr-old cows had reduced luteal activity, more days to AI, and lower pregnancy rate than 3-yr-old and mature cows. There was no difference among age classes for first-service conception rate, DMI, or OM digestibility.

	Footnotes

 
¹ Approved for publication by the director of the Oklahoma Agric. Exp. Stn. This research was supported under project H-2464.

² Corresponding author: jpbanta{at}ag.tamu.edu

Received for publication June 28, 2007. Accepted for publication April 17, 2008.

	LITERATURE CITED

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 


Alexander, B. M., B. W. Hess, D. L. Hixon, B. L. Garrett, D. C. Rule, M. McFarland, J. D. Bottger, D. D. Simms, and G. E. Moss. 2002. Influence of prepartum fat supplementation on subsequent beef cow reproduction and calf performance. Prof. Anim. Sci. 18:351–357.[Abstract/Free Full Text]

Technology, A. N. K. O. M. 2005a. Method for Determining Neutral Detergent Fiber (aNDF). http://www.ankom.com/09_procedures/procedures2.shtml Accessed May 8, 2005.

Technology, A. N. K. O. M. 2005b. Method for Determining Acid Detergent Fiber. http://www.ankom.com/09_procedures/procedures1.shtml Accessed May 8, 2005.

AOAC. 2005. Official Methods of Analysis of AOAC International. 18th ed. Assoc. Off. Anal. Chem., Arlington, VA.

Banta, J. P., D. L. Lalman, F. N. Owens, C. R. Krehbiel, and R. P. Wettemann. 2006. Effects of interval-feeding whole sunflower seeds during mid to late gestation on performance of beef cows and their progeny. J. Anim. Sci. 84:2410–2417.[Abstract/Free Full Text]

Banta, J. P., D. L. Lalman, and R. P. Wettemann. 2005. Symposium paper: Post-calving nutrition and management programs for two-yr-old beef cows. Prof. Anim. Sci. 21:151–158.[Abstract/Free Full Text]

Bellows, R. A., E. E. Grings, D. D. Simms, T. W. Geary, and J. W. Bergman. 2001. Effects of feeding supplemental fat during gestation to first-calf beef heifers. Prof. Anim. Sci. 17:81–89.[Abstract/Free Full Text]

Beef Improvement Federation. 2002. Guidelines for Uniform Beef Improvement Programs. 8th ed. Beef Improv. Fed., Athens, GA.

Bottger, J. D., B. W. Hess, B. M. Alexander, D. L. Hixon, L. F. Woodard, R. N. Funston, D. M. Hallford, and G. E. Moss. 2002. Effects of supplementation with high linoleic or oleic cracked saf- flower seeds on postpartum reproduction and calf performance of primiparous beef cow. J. Anim. Sci. 80:2023–2030.[Abstract/Free Full Text]

Brokaw, L., B. W. Hess, and D. C. Rule. 2001. Supplemental soybean oil or corn for beef heifers grazing summer pasture: Effects on forage intake, ruminal fermentation, and site and extent of digestion. J. Anim. Sci. 79:2704–2712.[Abstract/Free Full Text]

Byers, F. M., and G. T. Schelling. 1988. Lipids in ruminant nutrition. Pages 298–312 in The Ruminant Animal: Digestive Physiology and Nutrition. D. C. Church, ed. Waveland Press Inc., Englewood Cliffs, NJ.

Ciccioli, N. H., R. P. Wettemann, L. J. Spicer, C. A. Lents, F. J. White, and D. H. Keisler. 2003. Influence of body condition at calving and postpartum nutrition on endocrine function and reproductive performance of primiparous beef cow. J. Anim. Sci. 81:3107–3120.[Abstract/Free Full Text]

Coppock, C. E., and D. L. Wilks. 1991. Supplemental fat in high-energy rations for lactating cows: Effects on intake, digestion, milk yield, and composition. J. Anim. Sci. 69:3826–3837.[Abstract]

De Fries, C. A., D. A. Neuendorff, and R. D. Randel. 1998. Fat supplementation influences postpartum reproductive performance in Brahman cows. J. Anim. Sci. 76:864–870.[Abstract/Free Full Text]

DeJarnette, J. M., R. B. House, W. H. Ayars, R. A. Wallace, and C. E. Marshall. 2004. Synchronization of estrus in postpartum beef cows and virgin heifers using combinations of melengestrol acetate, GNRH, and PGF₂. J. Anim. Sci. 82:867–877.[Abstract/Free Full Text]

Doornbos, D. E., R. A. Bellows, P. J. Burfening, and B. W. Knapp. 1984. Effects of dam age, prepartum nutrition and duration of labor on productivity and postpartum reproduction in beef females. J. Anim. Sci. 59:1–10.[Abstract/Free Full Text]

Funston, R. N., T. W. Geary, R. P. Ansotegui, R. J. Lipsey, and J. A. Patterson. 2002. Supplementation with whole sunflower seeds before artificial insemination in beef heifers. Prof. Anim. Sci. 18:254–257.[Abstract/Free Full Text]

Geary, T. W., E. E. Grings, M. D. MacNeil, and D. H. Keisler. 2002. Effects of feeding high linoleate safflower seeds prepartum on leptin concentration, weaning, and re-breeding performance of beef heifers. Proc. West. Sec. Am. Soc. Anim. Sci. 53:425–427.

Graham, K. K., J. F. Bader, D. J. Patterson, M. S. Kerley, and C. N. Zumbrunnen. 2001. Supplementing whole soybeans prepartum increases first service conception rate in postpartum suckled beef cows. J. Anim. Sci. 79(Suppl. 2):106. (Abstr.)

Grings, E. E., R. E. Short, M. Blummel, M. D. MacNeil, and R. A. Bellows. 2001. Prepartum supplementation with protein or fat and protein for grazing cows in three seasons of calving. Proc. West. Sec. Am. Soc. Anim. Sci. 52:501–504.

Grummer, R. R. 1988. Influence of prilled fat and calcium salt of palm oil fatty acids on ruminal fermentation and nutrient digestibility. J. Dairy Sci. 71:117–123.[Abstract/Free Full Text]

Hess, B. W., G. E. Moss, and D. C. Rule. 2008. A decade of developments in the area of fat supplementation research with beef cattle and sheep. J. Anim. Sci. 86(E. Suppl.):E188–E204.[Abstract/Free Full Text]

Hess, B. W., D. C. Rule, and G. E. Moss. 2002. High fat supplements for reproducing beef cows: Have we discovered the magic bullet? 2002 Pacific Northwest Animal Nutrition Conference. http://www.dsm.com/en_US/downloads/dnpus/PNW_02_10.pdf Accessed Jan. 31, 2005.

Howlett, C. M., E. S. Vanzant, L. H. Anderson, W. R. Burris, B. G. Fieser, and R. F. Bapst. 2003. Effect of supplemental nutrient source on heifer growth and reproductive performance, and on utilization of corn silage-based diets by beef steers. J. Anim. Sci. 81:2367–2378.[Abstract/Free Full Text]

Hussein, H. S., N. R. Merchen, and G. C. Fahey Jr. 1995. Effects of forage level and canola seed supplementation on site and extent of digestion of organic matter, carbohydrates, and energy by steers. J. Anim. Sci. 73:2458–2468.[Abstract]

Jenkins, T. C. 1993. Lipid metabolism in the rumen. J. Dairy Sci. 76:3851–3863.[Abstract/Free Full Text]

Johnson, C. R., D. L. Lalman, M. A. Brown, L. A. Appeddu, D. S. Buchanan, and R. P. Wettemann. 2003. Influence of milk production potential on forage dry matter intake by multiparous and primiparous Brangus females. J. Anim. Sci. 81:1837–1846.[Abstract/Free Full Text]

Kucuk, O., B. W. Hess, P. A. Ludden, and D. C. Rule. 2001. Effect of forage:concentrate ratio on ruminal digestion and duodenal flow of fatty acids in ewes. J. Anim. Sci. 79:2233–2240.[Abstract/Free Full Text]

Lammoglia, M. A., R. A. Bellows, E. E. Grings, J. W. Bergman, S. E. Bellows, R. E. Short, D. M. Hallford, and R. D. Randel. 2000. Effects of dietary fat and sire breed on puberty, weight, and reproductive traits of F₁ beef heifers. J. Anim. Sci. 78:2244–2252.[Abstract/Free Full Text]

Lammoglia, M. A., R. A. Bellows, E. E. Grings, J. W. Bergman, S. E. Bellows, R. E. Short, and M. D. MacNeil. 1997. Effects of dietary fat composition and content, breed and calf sex on birth weight, dystocia, calf vigor and postpartum reproduction of first calf beef heifers. Proc. West. Sec. Am. Soc. Anim. Sci. 48:81–84.

Moore, J. A., R. S. Swingle, and W. H. Hale. 1986. Effects of whole cottonseed, cottonseed oil or animal fat on digestibility of wheat straw diets by steers. J. Anim. Sci. 63:1267–1273.[Abstract/Free Full Text]

NRC. 1996. Nutrient Requirements of Beef Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.

NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.

Palmquist, D. L. 1991. Influence of source and amount of dietary fat on digestibility in lactating cows. J. Dairy Sci. 74:1354–1360.[Abstract]

Palmquist, D. L. 1994. The role of dietary fats in efficiency of ruminants. J. Nutr. 124:1377S–1382S.[Abstract/Free Full Text]

Scholljegerdes, E. J., B. W. Hess, G. E. Moss, D. L. Hixon, and D. C. Rule. 2004. Influence of supplemental cracked high-linoleate or high-oleate safflower seeds on site and extent of digestion in beef cattle. J. Anim. Sci. 82:3577–3588.[Abstract/Free Full Text]

Smith, N. E., L. S. Collar, D. L. Bath, W. L. Dunkley, and A. A. Franke. 1981. Digestibility and effects of whole cottonseed fed to lactating cows. J. Dairy Sci. 64:2209–2215.[Abstract/Free Full Text]

Spitzer, J. C., D. G. Morrison, R. P. Wettemann, and L. C. Faulkner. 1995. Reproductive responses and calf birth and weaning weight as affected by body condition at parturition and postpartum weight gain in primiparous beef cows. J. Anim. Sci. 73:1251–1257.[Abstract]

Steele, J. D., J. P. Banta, R. P. Wettemann, C. R. Krehbiel, and D. L. Lalman. 2007. Drought-stressed soybean supplementation for beef cows. Prof. Anim. Sci. 23:358–365.[Abstract/Free Full Text]

Triplett, B. L., D. A. Neuendorff, and R. D. Randel. 1995. Influence of undegraded intake protein supplementation on milk production, weight gain, and reproductive performance in postpartum Brahman cows. J. Anim. Sci. 73:3223–3229.[Abstract]

Van Soest, P. J., J. B. Robertson, and B. A. Lewis. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583–3597.[Abstract]

Vargas, C. A., T. A. Olson, C. C. Chase Jr., A. C. Hammond, and M. A. Elzo. 1999. Influence of frame size and body condition score on performance of Brahman cattle. J. Anim. Sci. 77:3140–3149.[Abstract/Free Full Text]

Vizcarra, J. A., R. P. Wettemann, T. D. Braden, A. M. Turzillo, and T. M. Nett. 1997. Effect of gonadotropin-releasing hormone (GnRH) pulse frequency on serum and pituitary concentrations of luteinizing hormone and follicle-stimulating hormone, GnRH receptors, and messenger ribonucleic acid for gonadotropin subunits in cows. Endocrinology 138:594–601.[Abstract/Free Full Text]

Webb, S. M., A. W. Lewis, D. A. Neuendorff, and R. D. Randel. 2001. Effects of dietary rice bran, lasalocid, and sex of calf on postpartum reproduction in Brahman cows. J. Anim. Sci. 79:2968–2974.[Abstract/Free Full Text]

White, F. J., R. P. Wettemann, M. L. Looper, T. M. Prado, and G. L. Morgan. 2002. Seasonal effects on estrous behavior and time of ovulation in nonlactating beef cows. J. Anim. Sci. 80:3053–3059.[Abstract/Free Full Text]

Whittier, J. C., G. P. Lardy, and C. R. Johnson. 2005. Symposium paper: Pre-calving nutrition and management programs for two-year- old beef cows. Prof. Anim. Sci. 21:145–150.[Abstract/Free Full Text]

Williams, G. L., and R. L. Stanko. 2000. Dietary fats as reproductive nutraceuticals in beef cattle. Proc. Am. Soc. Anim. Sci. 1999. http://www.asas.org/jas/symposia/proceedings/0915.pdf Accessed Jan. 31, 2005.

Wiltbank, J. N. 1970. Research needs in beef cattle reproduction. J. Anim. Sci. 31:755–762.[Abstract/Free Full Text]

Yavas, Y., and J. S. Walton. 2000. Postpartum acyclicity in suckled beef cows: A review. Theriogenology 54:25–55.[CrossRef][Medline]

This article has been cited by other articles:

				N. M. Long, G. M. Hill, J. F. Baker, W. M. Graves, D. H. Keisler, and B. G. Mullinix Jr. Case Study: Reproductive Performance of Beef Cows Fed Whole Soybeans Before the Breeding Interval Professional Animal Scientist, December 1, 2008; 24(6): 639 - 647. [Abstract] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: jas.2007-0383v1 86/8/1868    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Banta, J. P. Articles by Wettemann, R. P. Search for Related Content PubMed PubMed Citation Articles by Banta, J. P. Articles by Wettemann, R. P.