Translational Animal Science最新文献

This experiment evaluated the effects of replacing one-third of corn grain in a finishing diet with rye grain (RG) processed using one of three processing methods. Predominately Angus steers (n = 192, initial shrunk BW = 410 ± 20.9 kg) were blocked by source and pen location and assigned to one of four dietary treatments: dry-rolled corn (DRC), unprocessed RG (UNP), dry-rolled RG (DRR) and hammer-milled RG (HMR). Steers were fed for a total of 147 d. Pen was the experimental unit (6 pens per treatment, 8 steers per pen), and data were analyzed as a randomized complete block design using three contrasts: grain type [DRC vs. (UNP + DRR + HMR)], RG processing (UNP vs (DRR + HMR), and RG processing method (DRR vs HMR). Processing RG increased (P = 0.02) apparent neutral detergent fiber digestibility (aNDFD). Dry-rolling RG increased digestibility of dry matter and organic matter (P ≤ 0.02) and tended (P = 0.09) to increase starch digestibility compared to HMR. Dry matter intake (DMI) was unaffected by grain type (P = 0.55) and whether RG was processed (P = 0.27), but processing method affected DMI (P < 0.01; 11.5 and 12.3 kg/d for DRR and HMR, respectively). Grain type did not affect (P = 0.18) gain to feed (G:F). Rye processing tended to increase G:F by 4.4% (P = 0.08), and DRR steers tended to be 4% more efficient than HMR steers (P = 0.10; 0.146 and 0.140, respectively). Observed Net Energy for gain (paNEg) tended to be 3% greater for DRC than steers fed RG (P = 0.09) with RG processing having no effect (P = 0.17). Steers fed DRR tended to have 4.5% greater paNEg than HMR steers (P = 0.06; 1.32 and 1.26 Mcal/kg, for DRR and HMR, respectively). Rye grain processing tended to decrease dressing percentage (P = 0.07) but no other effects on carcass characteristics or USDA grade distributions were observed (P ≥ 0.24). Liver abscess prevalence was unaffected by grain type (P = 0.81) and whether RG was processed (P = 0.77). However, processing method tended (P = 0.08) to influence liver abscess prevalence (78.4% and 91.8% normal livers for DRR and HMR, respectively). Rye grain effectively replaced one-third of DRC in a finishing diet with minor effects on performance or feed efficiency. Processing RG tended to improve efficiency, and using dry-rolling tended to improve feed efficiency compared to hammer-milling under the conditions of this experiment.

This experiment evaluated the effects of supplementing yeast culture (YC; Saccharomyces cerevisiae) on in situ ruminal degradability, rumen fermentation and microbiota responses of heifers consuming a forage-based diet. Twelve ruminally-cannulated Angus-influenced heifers were ranked by body weight (BW; 180 ± 4 kg) and assigned to 4 groups of 3 heifers each. Groups were enrolled in a replicated 3 × 3 Latin square design containing 3 periods of 21 d and 14-d washout intervals. Groups were assigned to receive no YC (CON), or 1.5 g of YC/100 kg of heifer BW (YC1.5) or 3.0 g of YC/100 kg of heifer BW (YC3.0). During each period, heifers (n = 12/treatment) were housed in individual pens and offered water and bermudagrass hay (Cynodon dactylon) for ad libitum consumption, in addition to 650 g/d (as-fed basis) of a corn-based concentrate. The YC was mixed daily with the concentrate during each period (d 0 to 21). Ruminal in situ disappearance of forage dry matter (DM) and neutral detergent fiber (NDF) were evaluated by incubating polyester bags with 4 g of dietary hay on d 17 for 96 h. Rumen fluid samples were collected on d 0, 8, and 16, in a manner that the final collection (d 16) did not interfere with in situ procedures on d 17. Apparent total-tract digestibility (aTTD) of nutrients was calculated using fecal samples collected every 12-h from d 17 to 21. Data were analyzed using orthogonal contrasts (linear and quadratic) with heifer as the experimental unit. Feed intake was not affected (P ≥ 0.14) by treatments. Inclusion of YC linearly increased (P ≤ 0.04) propionate and iso-butyrate concentrations in the rumen fluid, and tended (P ≤ 0.09) to increase acetate and total volatile fatty acid (VFA) concentrations. Inclusion of YC linearly decreased (P = 0.03) the relative abundance of the bacterial genus Succiniclasticum, and linearly increased (P = 0.04) genera Shannon diversity index in the rumen fluid. Inclusion of YC linearly increased (P ≤ 0.05) ruminal disappearance rate of hay DM and NDF, but did not affect (P ≥ 0.40) degradability of DM and NDF. Inclusion of YC linearly increased (P ≤ 0.05) aTTD of starch and NDF. Inclusion of YC linearly increased (P = 0.04) heifer average daily gain and gain:feed (G:F). Collectively, supplementing 1.5 or 3.0 g of YC/100 kg of BW linearly enhanced utilization of dietary nutrients and production of ruminal VFA in beef heifers consuming a forage-based diet.

This study was conducted to evaluate the effects of dietary medium-chain fatty acid (MCFA) levels on growth performance, fecal score, gut permeability, energy status, and apparent total tract digestibility (ATTD) of weaning pigs. At weaning, a total of 100 pigs [18.4 ± 1.8 d of age; initial body weight (BW) of 5.72 ± 1.4 kg] were allotted to 5 treatments in 5 replicates with 4 pigs per pen for a 35-d feeding trial. Treatments were dietary MCFA levels of 0.0, 0.2, 0.5, 1.0, and 1.5% for d 0 to 21 postweaning (Phase 1) replacing soybean oil and a common nursery diet was fed to all pigs for d 21 to 35 postweaning (Phase 2). With increasing dietary MCFA levels, quadratic increases were observed in BW (P ≤ 0.05), average daily gain (ADG; P ≤ 0.05), and average daily feed intake (ADFI; P = 0.08, tendency) in d 0 to 14 postweaning, peaking at the 0.5% MCFA level. The BW from d 21 to 35 postweaning and ADG in d 0 to 21 and 21 to 35 postweaning increased linearly with increasing MCFA levels (P ≤ 0.05), while linear and quadratic increases were observed in overall ADG (P ≤ 0.05), with the greatest value observed at the 1.0% MCFA level. The ADFI increased linearly (P ≤ 0.05) with increasing MCFA levels in d 21 to 35 postweaning and overall period, while gain-to-feed ratio was not different in each phase and overall period. Fecal score was not affected in the overall period (P > 0.21). The ATTD of gross energy (P ≤ 0.05), dry matter (P = 0.10, tendency) and crude protein (P = 0.07, tendency) increased linearly with increasing MCFA levels. At d 7 postweaning, plasma β-hydroxybutyrate levels decreased linearly (P = 0.06, tendency) with increasing MCFA levels, while plasma free fatty acid levels showed a quadratic response (P = 0.06, tendency) with the lowest levels at the 0.5% MCFA level. Increasing MCFA levels decreased plasma diamine oxidase levels at d 7 postweaning (P = 0.06, tendency), while showing quadratic decreases in plasma d-lactate levels at d 7 (P ≤ 0.05) and 21 (P = 0.10, tendency) postweaning, with lower values observed at the 0.2% to 1.0% MCFA levels compared to the 0.0% MCFA level. In conclusion, increasing dietary MCFA levels up to 1.0% enhanced overall growth rate and feed intake, energy and protein digestibility in nursery pigs, improved energy status by lowering plasma β-hydroxybutyrate and free fatty acid levels, and reduced gut permeability in the early nursery period.

[This corrects the article DOI: 10.1093/tas/txae158.].

A total of 87 sows (Line 241, DNA) and their offspring were used to evaluate the effects of increasing standardized ileal digestible (SID) Lys in late gestation diets on lactating sow and litter performance. Sows were blocked by parity and body weight (BW) on day 90 of gestation and allotted to one of three treatments with 29 replications per treatment. Diets included increasing dietary SID Lys (0.60, 0.80, or 1.00%) accomplished by increasing soybean meal (14, 21, or 29% of the diet). Sows were allowed 2.04 kg/d of their treatment diet from day 90 of gestation until farrowing for average SID Lys intakes of 11.9, 15.8, or 19.9 g/d. After farrowing, sows had ad libitum access to a common lactation diet containing 1.10% SID Lys. Urine samples were collected on day 90 and 110 of gestation to determine urinary creatinine levels. Litters were cross-fostered within dietary treatment by 48 h after farrowing to equalize litter size. Parity group was included in the statistical model as a fixed effect with classifications of primiparous (n = 35) or multiparous (n = 52) sows. Weight gain from day 90 to 110 of gestation increased (linear, P < 0.001) as SID Lys increased. Change in urinary creatinine level from day 90 to 110 of gestation tended to decrease (linear, P = 0.063) as SID Lys increased suggesting that muscle catabolism decreased with increasing SID Lys. There were no differences in starting litter size or piglet birth weight with increasing SID Lys in late gestation. Piglet average daily gain (ADG) from day 2 to 10 of lactation increased (linear, P = 0.017) as SID Lys increased. From day 2 until weaning, litters from sows fed 15.8 g/d of SID Lys in gestation had the greatest (quadratic, P = 0.044) litter weight gain. Pre-weaning mortality from birth until day 2 of lactation was greatest for sows fed 15.8 g/d of SID Lys (quadratic, P = 0.025). There was a parity group × gestation diet interaction (P = 0.049) for pre-weaning mortality from day 2 to weaning where mortality increased as SID Lys increased in primiparous sows but decreased in multiparous sows. However, the differences in mortality did not influence the number of pigs weaned per treatment. In conclusion, increased SID Lys through increased soybean meal linearly increased late gestation sow BW gain and piglet ADG during early lactation. Litters from sows fed 15.8 g/d of SID Lys had the greatest litter ADG during late lactation and overall.

While boars constitute a relatively small portion (less than 0.005%) of the total swine herd, they have significant genetic influence on the swine population. An individual boar has the potential to sire thousands of offspring every year, yet when it comes to science-based recommendations for boar development from weaning to puberty, there is little in the way of recommendations. Similarly, the management and nutritional recommendations of today's boar population are based on studies that may not be relevant to current genetics or based on recommendations for gilts and sows. Historically with rapid genetic turnover in boar studs there has been little pressure to produce research in this area. However, with boar studs reporting increasing incidence of lameness and health related removals, rising developmental costs, and a need to maintain herd fertility it has created opportunities to increase the scientific understanding of boar development and management. In this literature review, we aim to overview development and management of commercial boars in the United States and highlight what is understood in the way of science-based research.

[This retracts the article DOI: 10.1093/tas/txae125.].

A 3-yr study evaluated the effect of late gestation supplementation strategy on cow-calf performance, subsequent steer feedlot performance, and carcass characteristics. Mature March-calving crossbred cows (n = 357) were stratified by body weight (BW) and body condition score (BCS) and assigned to one of 4 treatments: 1) no supplementation (NoSupp), 2) 0.91 kg/d of a 30% CP distillers-based supplement (DBS) (Supp), 3) 0.91 kg/d of a 30% CP DBS with 160 mg/cow/d of monensin (RUM; Rumensin 90, Elanco Animal Health), and 4) 0.91 kg/d of a 30% CP DBS with 40 g/cow/d propionate salt (CaProp, NutroCal 100, Kemin Industries). Cows were individually supplemented daily using a Super SmartFeed (C-Lock Inc., Rapid City, SD) from November to February. After weaning, steers (n = 181) were transported to the West Central Research and Extension Center and placed in a GrowSafe feeding system for finishing. Steers were slaughtered at a commercial facility (Tyson Fresh Meats, Lexington, NE) after fed to a common endpoint each year. Cow BW was not different (P = 0.87) at the initiation of the study in November. However, NoSupp cows were lighter (P < 0.01) at pre-calving and pre-breeding compared to supplemented cows. In contrast, NoSupp cows lost less (P < 0.01) BW from pre-calving to pre-breeding than supplemented cows and gained more (P = 0.01) BW from pre-breeding to weaning. Treatment tended to influence overall pregnancy rates (P = 0.09). Supp and CaProp dams had increased pregnancy rates over NoSupp and RUM (P ≤ 0.05). Offspring from NoSupp dams had lighter (P < 0.01) BW at birth, pre-breeding, and weaning than their counterparts from supplemented dams. In addition, steer feedlot entry, final BW, and hot carcass weight were greater (P < 0.01) when dams were supplemented compared to NoSupp. Steer feedlot average daily gain and gain:feed ratio was not influenced (P ≥ 0.31) by dam supplementation strategies; however, dry matter intake tended (P = 0.09) to be influenced by treatment. Percentage of carcasses grading Choice or greater was not influenced (P = 0.66) treatment; however, steers from dams fed CaProp had increased (P = 0.04) marbling scores. Protein supplementation during late gestation is an effective strategy to increase cow BW, maintain cow BCS, and increase progeny BW. Providing dams with propionate salts during late gestation positively improved marbling score of the subsequent steer carcass characteristics.

The objective of this study was to evaluate the effects of a Saccharomyces cerevisiae fermentation product (SCFP) compared to a direct-fed microbial (DFM) on growth performance, health, carcass characteristics, and liver abscess prevalence in beef × dairy crossbred steers. Two thousand steers [50% beef, 25% Holstein, 25% Jersey genetics; initial shrunk body weight (SBW) = 288.2 ± 8.0 kg] were blocked by arrival date and randomly assigned to receive 1 of 2 treatments: 1) SCFP supplied in the starter diet at 12 g per steer daily and then 9 g per steer daily in the finishing diet (NS; NaturSafe™, Diamond V, Cedar Rapids, IA) or 2) DFM fed at 50 mg per steer daily throughout the feeding period (BD; Bovamine Defend, Chr. Hansen, Milwaukee, WI). Pen served as the experimental unit (200 steers/pen), with 5 pens per treatment. Data were analyzed as a randomized complete block design in R 4.2.2. with the main effect of treatment and random effect of block included in the model. Results were reported on a deads-in basis unless otherwise stated. Cattle were fed for a total of 275 ± 6.2 d. Initial and final SBW did not differ (P ≥ 0.84) by treatment. Initial treatment pulls were observed more frequently for NS compared to BD cattle (29.43% vs. 21.67%; P < 0.01). However, NS cattle had a lesser rate of repulls as a proportion of initial pulls (10.08% vs. 16.61%; P = 0.03). Fewer (P < 0.01) bullers were reported amongst NS cattle. Cattle supplemented with NS had a lower case fatality rate (6.08% vs. 11.96%; P < 0.01) and tended to have a lower total mortality rate (1.60% vs. 2.70%; P = 0.09) than BD. With deads included, average daily gain (ADG) tended (P = 0.06) to be greater for NS cattle. Dry matter intake did not differ (P = 0.99) by treatment; however, NS cattle had a numeric advantage in feed efficiency (G:F) nearing a tendency (0.132 vs. 0.130; P = 0.11). On a deads-out basis, ADG and G:F were similar (P ≥ 0.85). Dressing percentage tended (P ≤ 0.10) to be greater for NS carcasses. Cattle fed BD had a greater (P = 0.03) proportion of USDA Prime carcasses. While treatment had no impact on liver abscess severity or total abscess occurrence, NS cattle tended to have less A- abscesses (1.72% vs. 3.87%; P = 0.10). In this large-pen comparison, SCFP supplementation improved feedlot cattle health and positively influenced performance compared to a DFM.

Cannabis sativa (varieties for industrial use or animal feed are termed hemp), and its extracted byproducts are being considered for animal feed due to their high protein content. However, if hemp disrupts fertility and reproduction in livestock, it should not be used as a feed source. We hypothesized that the phytocannabinoids in hemp would disrupt fertility and reproduction, cause craniofacial defects (cyclops, cleft palate, misshapen head), and low birth weight in lambs. To test this hypothesis, 22 timed pregnant ewes were dosed with hemp in the form of dried ground hemp plant material at 150 mg/kg body weight per day total cannabinoids, and from gestational days 10 to 20 and a separate 22 timed pregnant ewes were dosed similarly with dried ground grass hay as a control. The most prevalent cannabinoids in the plant material were cannabidiolic acid (CBDA) at a concentration of 23.2 mg/g, and cannabidiol (CBD) at a concentration of 5.8 mg/g. Delta 9-tetrahydrocannabidiol was present in the plant material at a concentration of 0.3 mg/g. The hemp used in this study had crude protein concentrations of 15.6%, neutral detergent fiber concentrations of 42.2%, and in vitro true digestibility concentrations of 83.6%. After 10 d of dosing with hemp, a serum sample was obtained from each of the ewes, CBDA was measured at a concentration of 652 ± 38 ng/mL and CBD was measured at 16 ± 0.9 ng/mL. THC was not detected in the serum. The average gestation length for lambs from the hemp treated ewes was 148 ± 0.38 d, and the average gestation length for lambs from the grass hay treated ewes was 149 ± 0.38 d (P = 0.23). The numbers of male and female lambs did not significantly vary from expected (50:50) (P = 0.32). There were no significant fetal deformities (P > 0.05) or weight differences between the treatment groups (P > 0.05), and as expected, the lamb weights significantly increased over time (P < 0.05). These results suggest that Cannabis sativa may have the potential with further research to be a suitable protein source for gestating sheep.