Translational Animal Science最新文献

Vitamin A is an essential nutrient with an important role in animal health across livestock species. Insufficient dietary vitamin A intake is associated with decreased reproductive performance in females as well as impaired growth performance and health of the offspring. The aim of this study was to determine if an intramuscular injection of vitamin A and D (VitAD) given to sows on d 85 of gestation improved the survivability, growth performance, and health of the offspring from birth through the end of the nursery phase. Yorkshire or Yorkshire cross bred sows received either an injection of VitAD (312,000 IU vitamin A, 52,500 IU vitamin D. n = 9) or saline control (n = 10). At farrowing, birth weights, survival, and umbilical blood was collected on the piglets, and colostrum was collected from sows. Daily weights were taken from d 0 to 4, then weekly weights from d 8 to 63 on all pigs. Milk samples were taken weekly on sows from birth to weaning (d 28), and daily feed consumption for the sows was tracked during the lactation phase. Blood samples were obtained weekly from piglets through weaning (d 28). Subsequent blood samples were taken weekly through the nursery phase (d 28-d 63) from a subset of the original pigs to measure retinol from birth to d 63 and immune parameters from d 28 to d 63. All statistical analyses were run using a mixed linear regression model on SAS (9.4; SAS, Cary, NC). VitAD piglets tended to have a reduced average daily gain (ADG) from d 22 to d 28 (P = 0.08), and decreased circulating retinol concentrations on d 15, 22, and 28 (P ≤ 0.05) compared to control piglets. Fewer stillborn piglets (P = 0.01) were present in litters from sows treated with Vit AD compared to control sows. VitAD pigs had an elevated reticulocyte count on d 42 (P ≤ 0.01) compared to the control pigs. VitAD treated sows consumed less feed on d 15 (P ≤ 0.05) and had greater milk retinol (P ≤ 0.01) on d 8 of lactation compared to control sows. These results suggest that the administration of an injection of VitAD to sows on d 85 of gestation might improve offspring survival at birth, as well as decrease sow nutritional consumption requirements during lactation. Additionally, these results help to establish normal immune parameters and circulating retinol in pigs. Importantly, no negative effect of VitAD supplementation on growth rate or immune parameters was observed.

The use of multi-sire breeding pastures is a common practice in Western Canada for beef cattle management. However, the number of progenies sired by each bull may not be known or producers will not be sure if performance traits were passed on. Hybrid vigor is defined as the superiority of crossbred progeny over their parents' average to increase production efficiency, longevity and reproductive rate of beef cows. A DNA parentage test was performed to identify relative sires to their progeny. Then, 109 bull prolificacy indexes (BPI) were calculated for 46 sires over 6 breeding seasons (some had more than one BPI). They ranged from 0.04 to 3.47, with values larger than one showing high prolific sires. Yearling sires had a significantly lower BPI value than 2-year-old and mature bulls. Regardless of the level of BPI, each sire produced the majority of all his born calves in the first cycle of the calving period (R² = 0.89). This demonstrated the importance of identifying high BPI sires, as they showed a tendency to have a greater percentage of the first cycle born grand calves from their first cycle born heifers (R² = 0.86). Also, they produced a greater number of grand calves from their retained daughters with a significant impact on total kg weaned (P < 0.01). The EnVigour HX™ test was applied to estimate the effect of bulls' and heifers' vigor scores (scores were based on percentage) on fertility and production traits. The breeder's interest in the utilization of crossbred heifers and bulls positively affected the longevity of replacement females. There was a decrease in age at first calving relative to the EnVigour HX™ test commercialized suggestions per 10% increase in heifers' vigor scores. Moreover, larger productivity was observed for average WW per calf and cow life productivity, which could be due to different genomic breed compositions between this study and the test animals. Overall, DNA parentage and EnVigour HX™ tests are essential tools for beef cattle production profitability. However, up to a 75% vigor score cutoff is suggested when selecting crossbred females with EnVigour HX™ to retain production and fertility efficiency in crossing with Beef Booster bulls.

Our objectives were to determine the response curve of increasing supplementation rate with extruded distillers' grains (DDG) cubes for animal performance, supplement conversion ratio, and N excretion by steers grazing midgrass prairie in western Oklahoma. A 2-yr trial was conducted at the Marvin Klemme Range Research Station (Klemme) and the USDA-ARS Southern Plains Experimental Range (SPER) in western Oklahoma. At Klemme, steers (Yr 1, n = 133, BW = 247 ± 24.5 kg; Yr 2, n = 134, BW = 264 ± 29.1 kg) were allocated to 6 pastures in Yr 1 and 7 pastures in Yr 2 which were assigned to three daily supplementation rates of DDG cubes: (i) Negative Control (NC)- no supplementation; (ii) Low supplement (LS) - 0.91 kg/steer and (iii) Medium Supplementation (MS) - 1.82 kg/steer. At Klemme, steers were stocked at 2.0 ha/steer in yr 1 and 2.8 ha/steer in yr 2. At SPER steers (n = 119 each year; Yr 1, BW = 295 ± 28.8 kg; Yr 2, BW = 294 ± 25.7 kg) were allocated to 12 pastures stocked at 2.0 ha/steer with pastures assigned to: (i) NC; (ii) LS; (iii) MS and (iv) High Supplement-daily supplementation rate of 2.72 kg/steer. Data were analyzed by year and experimental site as a completely randomized design. Least-squares means were separated using orthogonal polynomial contrasts. In both years at Klemme, the increased supplementation rate linearly increased (P ≤ 0.01) average daily gain (ADG) but made no difference (P ≥ 0.16) in supplement conversion ratio. At SPER, ADG increased linearly (P < 0.01) in Yr 1, but quadratically (P = 0.05) in Yr 2; in both years, supplement conversion ratio displayed a quadratic response (P = 0.01), decreasing with increasing supplementation rate. These data suggest that supplementing extruded DDG cube to steers grazing native range is a viable option to intensify production on stocker operations. If forage availability and nutritive quality is adequate to support BW gains higher supplementation rates are likely not economically efficient, however if forage is limiting improved performance may be adequate for positive economic returns. The response curves observed in this research will allow producers to make supplementation decisions based on market and range conditions.

Two experiments were conducted to evaluate the effects of creep feeding on pre- and post-weaning pig performance. In Exp. 1, 96 sows (C29, PIC) and their litters were used to determine the effects of creep feed quality on pre-weaning growth and the proportion of piglets consuming creep feed. Litters were offered one of three treatments: (i) no creep feed, (ii) a simple creep diet, or (iii) a complex creep diet. The simple creep feed was the sow lactation diet which was sorghum-soybean meal based and formulated to 2554 kcal/kg NE and 0.92% standardized ileal digestible (SID) Lys. The complex creep feed was formulated to 2769 kcal/kg of NE, 1.44% SID Lys, 23% lactose, and composed of oat groats, dried whey, and specialty protein sources. Creep feed was offered from d 18 to 21 (weaning) of lactation. Chromic oxide was added to both diets at 1.0% as an inert, colored fecal marker to identify pigs that consumed (eaters) and did not consume creep feed (non-eaters). Pigs fed the complex creep diet had greater (P = 0.033) pre-weaning ADG and tended to have greater (P = 0.063) total gain than pigs fed the simple creep diet with pigs not offered a creep diet intermediate. Litters fed the complex creep diet consumed twice (P < 0.001) as much total and daily creep feed intake of litters fed the simple creep diet. Also, the complex creep diet improved (P < 0.001) the proportion of eaters from 28% to 68%. In Exp. 2, 675 pigs from Exp. 1 (initially 6.4 ± 0.13 kg; 21.2 ± 0.2 d) were used to evaluate whether placing eaters with non-eaters of creep feed would facilitate and increase intake and gain of non-eaters. Treatments were non-eaters (not provided any creep feed or non-eaters from creep fed litters), eaters (pigs that consumed the complex creep feed), and a mixed group (52% non-eaters and 48% eaters). Each treatment had 9 replicate pens with 25 pigs per pen. In the first 3 d, eaters had greater (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) than non-eaters with the mixed group intermediate. Overall (d 0 to 28), ADG of eaters was greater (P = 0.049) than non-eaters. In conclusion, the complex creep improved pre-weaning ADG, ADFI, and the proportion of eaters. Eaters had increased ADG and ADFI in the first 3 d post-weaning and greater overall nursery ADG. Additionally, mixing eaters with non-eaters within pens did not stimulate feed intake and growth of non-eaters, which indicates that social facilitation did not occur.

This study was conducted to investigate the effects of different stressors on physiological and innate immune variables in weaned dairy calves. Holstein steers (n = 40; 110 ± 11.8 kg body weight [BW]) were housed in individual pens in an environmentally controlled barn. Steers had ad libitum access to water and a starter ration. Steers were randomly allotted to four treatment groups (n = 10/treatment): (i) control (CON), (ii) transport (TRANS; transported in a livestock trailer for 4 h), (iii) lipopolysaccharide (LPS; administered i.v. 0.10 µg/kg BW), and (iv) vaccine (VAX; administered a Mannheimia haemolytica toxoid vaccine). One day prior to administration of stressors, indwelling jugular vein catheters and rectal temperature (RT) recording devices were placed in all steers. Whole blood was collected at -1, -0.5, 0, 1, 2, 3, and 4 h relative to administration of stressors for serum, plasma, and hematology. There was a treatment × time interaction (P ≤ 0.01) for all hematology parameters except for hemoglobin and platelets. Monocyte, lymphocyte, neutrophil, and white blood cell concentrations were reduced (P ≤ 0.02) in steers administered LPS compared to all other treatments. For steers administered the VAX treatment, white blood cell and neutrophil concentrations and the neutrophil: lymphocyte ratio increased (P ≤ 0.04) 4 h post-treatment application compared to other treatments. There was a treatment × time interaction (P < 0.01) for RT where values increased in LPS and VAX steers at 1 and 4 h, respectively, while RT decreased in TRANS steers at 5 and 6 h. There was a treatment × time interaction (P < 0.01) for cortisol concentrations, where steers administered LPS produced the greatest increase in cortisol compared to all other treatments. There was a treatment × time interaction (P ≤ 0.02) for all cytokines except for interleukin-13 (P = 0.12). Concentrations of these cytokines remained greater in LPS and VAX steers compare to CON and TRANS. These data demonstrate the differential immune responses to common challenges experienced by dairy calves.

Cobalt (Co) is essential for vitamin B₁₂ synthesis in the rumen and energy metabolism in cattle. Previous studies on organic Co sources have shown variable effects on dairy cows' performance, focusing primarily on Co glucoheptonate as an alternative to the traditional Co carbonate (CoCO₃). Our objective was to evaluate the effects of novel organic Co sources on ruminal microbial fermentation, nutrient degradation, and vitamin B₁₂ synthesis using a dual-flow continuous culture system. We used eight fermenters in a duplicated 4 × 4 Latin Square design, where each -fermenter was provided daily with 106 g DM of a basal diet plus the corresponding Co treatment. The treatments consisted of supplementing 1 mg Co/kg DM from the following Co sources: (i) CoCO₃, (ii) Co Pectin (CoPec), (iii) Co Amino Acid (CoAA), and (iv) Co Pectin + Co Amino Acid (CoPec+CoAA). Data were analyzed with the MIXED procedure of SAS 9.4 to evaluate the effect of Co source on pH, VFA, N metabolism, vitamin B₁₂ concentration and flows, and nutrient degradability. We did not find an effect of Co source on pH (P = 0.92) or concentrations of acetate (P = 0.32), propionate (P = 0.15), butyrate (P = 0.92), and other VFA. However, we found that D-lactate concentration was greater in CoCO₃ than other treatments (P = 0.03), and total lactate was greater in CoCO₃ compared to CoAA and CoPec+CoAA (P = 0.04). Vitamin B₁₂ in liquid outflow tended to be lower with CoCO₃ (P = 0.10). Moreover, there was greater bacterial N flow (P = 0.01) and also greater N use efficiency (P = 0.01) in CoAA than CoCO₃ and CoPec. For nutrient degradation, we found a greater ruminal degradability of NDF (P < 0.01) in CoAA and CoPec+CoAA compared to CoCO₃ and CoPec. Our results indicate that, at a supplementation rate of 1 mg Co per kg diet DM, the tested Co sources affected fermentation of ruminal contents in continuous culture. Specifically, under the conditions of this experiment with dairy cattle diets, CoAA promoted greater microbial protein synthesis, NDF degradability, and liquid-associated vitamin B₁₂ flow compared to CoCO₃ and CoPec, suggesting enhanced Co utilization by ruminal microorganisms when CoAA is included as the primary Co source in the diet.

The objective of this experiment was to determine if supplementation with a glycerol-based electrolyte solution in the drinking water prior to shipping for harvest increased carcass weight and enhanced carcass quality in beef steers. The solution used (HydraFit-Selko USA, Indianapolis IN) contained: potassium chloride, acetic acid, magnesium hydroxide, sodium propionate, and sodium chloride; 5.10% potassium, 1.00% sodium, and 0.87% magnesium. Steers (n = 40; 20 steers per treatment; BW = 659 ± 72.9 kg) were weighed 40 hour prior to harvest, blocked by BW (n = 4 BW blocks), and assigned to one of two treatments: no glycerol-based electrolyte solution (Control) or use of a glycerol-based electrolyte solution (GES) added to the water at 4% vol/vol (4 pens/treatment, 8 pens total). Feed and water access was not restricted nor was a shrink percentage applied to any BW measures. Thirty-six hours prior to harvest a 378 L water tank was filled with water from the same source the steers had been consuming for the previous 126 d. Water and feed were introduced 36 hour prior to harvest. Final BW was captured immediately before shipping (12 hour prior to harvest). Cattle were transported 98 km to a commercial abattoir. Cattle were held in lairage with ad libitum access to water prior to harvest the following morning. Water intake pre-shipment was determined after the cattle were removed from the pens and transported to slaughter, allowing 22.5 hours of access to feed and water prior to shipping. Water volume was estimated by measuring water depth remaining in the tank. Depth measurements were calibrated to water volume by metering (DM-P; Assured Automation, Roselle, NJ; ± 1.0%) 0.64 cm of water into each tank and recording the liters of water metered. Hot carcass weight was determined at the time of slaughter and cold carcass weight was determined after a 48-hour chill. Providing a glycerol-based electrolyte solution, Hydrafit, to finished beef cattle in their drinking water for approximately 22.5 hours prior to shipping for harvest tended to increase the final live weight (P = 0.08) by 1%, but had no effect (P ≥ 0.88) on hot or cold carcass weight.

This study explored whether thermal imaging could provide an objective means of body condition scoring (BCS) horses and multiparous, gestating beef cows. This study consisted of two parts: one part assessed BCS in horses of the Quarter Horse or Thoroughbred breed types while the other evaluated BCS of gestating beef cows. Ground truth BCS were assigned by five to eight trained scorers for each animal. Thermal images were also collected from one or both sides of the body and analyzed for surface temperature. Surface temperature and BCS were evaluated with the whole body, and for five (cows) or seven (horses) specific body regions. Covariates were monitored, including breed, ambient temperature, cloud coverage (%), housing conditions, blanketing status, individual scorer, and scorer's location. Considerable between-scorer variation in BCS assigned was apparent in both species, with 58% to 65% of observations falling within 0.5 BCS of the median. Much of the variability was attributable to scoring the degree of BCS deviation from normal, and 72% to 82% of scores agreed in directional accuracy. Scaled, centered scores within 0.5 units of the median BCS were defined as high-agreement data. Random forest regressions were derived to explore how well thermal-camera-obtained body surface temperature data could be used to estimate BCS of horses and cows using either all available data or the subset of high-agreement data. In both datasets, 15% of observations were used for hyperparameter tuning, 55% for model-training, and 30% for independent evaluation. Unique models were created for each body area assigned a BCS for horses (the neck, shoulder, withers, ribs, loin, tailhead, and overall) or beef cows (the brisket, shoulder, ribs and spine, hooks and pins, and overall). Models estimating horse BCS had lower RMSE (6.71% to 10.4%) and higher accuracy (62.7% to 90.3%) than those estimating cow BCS (RMSE: 6.39% to 15.9%; accuracy: 46.8% to 82.5%). Models derived from all data had higher RMSE (7.76% to 15.9%) and lower accuracy (53.8% to 82.3%) compared with those derived from only high-agreement data (RMSE: 5.80% to 8.18%; accuracy: 66.7% to 90.3%). Overall, thermal imaging shows promise as an objective tool for BCS assignment in both horses and beef cows. However, future refinement of the method for assigning BCS ground truth is important.

Tall fescue [Schedonorus arundinaceus (Shreb.) Dumort.; (TF)] is the primary forage species used by cow-calf producers in grazing systems in Tennessee. It is an excellent cool-season perennial grass due to its great forage mass (FM), nutritive value, and extensive growing season. Orchardgrass [Dactylis glomerata L.; (OG)] is also a widely used cool-season grass in the U.S. This study compared TF and OG cultivars under continuous stocking in terms of FM, nutritive value, and animal performance over two grazing seasons (2022 to 2023) in Spring Hill, Tennessee, U.S. Treatments were: 1) OG cv. Persist I (OG-P1), 2) OG cv. Persist II (OG-P2), 3) TF cv. Kentucky 31' (TF-K31), and 4) a novel endophyte TF cv. Max Q (TF-NE). Forage mass was not affected by treatments (P = 0.0519), with an average of 2979 kg DM ha^-1. Crude protein (CP) and neutral detergent fiber (NDF) concentrations were also unaffected by treatments (P = 0.6728, P = 0.1300), averaging 106 and 687 g kg^-1, respectively. However, TF-NE had the lowest acid detergent fiber (ADF) (P = 0.0258; 380 g kg^-1) and the greatest in vitro dry matter digestibility in 48 hours (INVDMD48) (P < 0.0001; 680 g kg^-1), while OG-P2 had the greatest ADF (400 g kg^-1) and the lowest INVDMD48 (661 g kg^-1). Total gain and average daily gain (ADG) were affected by treatment × year interaction (P = 0.0314 and P = 0.0161, respectively). In 2022, TF-NE, TF-K31, and OG-P1 outperformed OG-P2, but no differences were observed in 2023 (total gain: 78.6 kg animal^-1; ADG: 0.78 kg animal^-1 day^-1). Ergovaline concentrations in TF-K31 were low, which likely minimized its negative effects. These findings indicate that both TF and OG can sustain beef cattle production under continuous stocking, with TF offering potential advantages in botanical composition and forage nutritive value over time.

This research was conducted to gain more insight into the productivity and good management practice (GMP) adoption of cow-calf operations in Río Negro Province, Argentina. The objectives were to characterize productivity and management profiles according to GMP adoption, identify herd clusters, and describe the performance and productivity within each specific cluster. A survey sample of 142 out of 1,229 cow-calf and cow-calf to-finish operations from Avellaneda and Pichi Mahuida counties provided data on productivity, herd structure, and GMP adoption. The productivity variables, calves per 100 cows (C/100 c) and calves per 100 ha (C/100 ha), were described statistically using quartiles, and differences by county according to the 3-month breeding season adoption were explored. Moreover, herd structure and GMP-related variables were subjected to multiple correspondence analysis (MCA) with complete-link hierarchical cluster analysis to typify the operations. A total of 127 out of 142 farmers provided productivity data, showing median values of 79.00 C/100 c (Q1 = 67.00; Q3 = 85.00) and 4.58 C/100 ha (Q1 = 2.78; Q3 = 8.00). A Significant difference was found between 3-month and year-round breeding operations for both variables (82.00 C/100 c vs 75.50 C/100 c; P = 0.0006 and 5.60 C/100 ha vs 3.97 C/100 ha; P = 0.0072). Three farm clusters (Cl) were identified: Cl 1 (low adoption), Cl 2 (moderate transition), and Cl 3 (GMP-oriented). Cl 3 showed the highest GMP adoption level, and a significant difference was found in the C/100 c variable (85.00 C/100 c vs. 76.00 and 80.00 for Cl 1 and 2, respectively; P = 0.0233). Cluster profiling enhances our understanding of the cow-calf operation segment and highlights the importance of GMP adoption for improving productivity in cow-calf operations. The results should be interpreted with caution due to the limitations of a cross-sectional study showing correlational associations. Nevertheless, it provides insights for designing science-based and targeted interventions to improve the performance of the beef cattle industry in Río Negro, Argentina, and may be the basis for prospective or interventions studies in the future.