Translational Animal Science最新文献

We conducted two experiments to evaluate the effect of direct-fed microbials (DFM) on fermentation parameters and nutrient degradability with two different approaches using rumen fluid from lactating Holstein dairy cows. In Exp. 1, three doses of a DFM containing Lactobacillus animalis and Propionibacterium freudenreichii (PRO-A) at doses of 3.9 × 10⁶, 7.8 × 10⁶, and 11.7 × 10⁶ CFU or a DFM containing PRO-A, Bacillus subtilis, and B. licheniformis (PRO-B) at doses of 15.2 × 10⁶, 30.4 × 10⁶, and 45.6 × 10⁶ CFU were incubated using corn silage as substrate and pooled rumen fluid from three-rumen fistulated lactating Holstein cows. Dry matter and NDF degradability, gas production, and rumen pH were measured over a 24-h period. In Exp. 2, three ruminally cannulated multiparous cows (165 ± 63 DIM) were used in a 3 × 3 Latin square design. Each experimental period was of 28 d. All cows received a corn silage-based TMR (basal diet), and were assigned to: 1) Control (CON), 2) PRO-A: Basal diet top-dressed with PRO-A at 3 × 10⁹ CFU/day, and 3) PRO-B: Basal diet top-dressed with PRO-B at 11.8 × 10⁹ CFU/day. An ex vivo study (Exp. 2) was conducted using rumen fluid collected during wk 4 of each experimental period from experimental animals. Treatments included: CON, PRO-A, PRO-B, each of which utilized rumen fluid from donor cows given respective treatments. Another set of rumen fluid from PRO-A and PRO-B cows were dosed with additional dose of respective DFM, resulting in two more treatments (PRO-A+ and PRO-B+). In Exp. 1, linear effects (P = 0.03) were observed on in vitro NDF degradability following DFM incubation. In Exp. 2, no treatment effects were observed on DM and NDF digestibility. In summary, DFM increased DM and NDF degradability in vitro using rumen fluid from cows not exposed to DFM; however, no effects were observed under ex vivo experimental conditions when rumen fluid was collected from cows consuming DFM.

Gastrointestinal nematode (GIN) infection adversely affects the performance and well-being of forage-based sheep throughout the world. The study objectives were to estimate longitudinal differences between birth seasons and production systems for lamb postweaning growth and indicators of GIN infection. Data were collected on Katahdin lambs within a single flock from 2006 to 2022. Lambs were born in either the winter or fall and reared in conventional or certified organic production systems. Four sub-flocks were defined as the combination of birth season and production system (winter-conventional = W-C, n = 1766; winter-organic = W-O, n = 190; fall-conventional = F-C, n = 846; and fall-organic = F-O, n = 189). All lambs were naturally infected with GIN from previously grazed pastures, weaned at approximately 60 d of age, and remained on pasture throughout the postweaning phase. At approximately 90, 120, and 150 d of age lamb body weight (BW) was recorded, and fecal egg count and blood packed cell volume (PCV) were quantified. Fecal egg count was log-transformed (LFEC) prior to analyses. Traits were initially analyzed within collection timepoint to compare all 4 sub-flocks. Final BW at 150 d and LFEC and PCV throughout the postweaning phase were similar between conventional and organic lambs born in the same season. Repeated measures models were then used to analyze records from W-C and F-C lambs over time. The collection timepoint × deworming treatment × sub-flock interaction effect was significant for all traits (P < 0.01). Within lambs that did not require deworming, no difference in BW between birth seasons was observed. However, LFEC trends for untreated F-C and W-C lambs were nearly exact opposite of one another, being greater for F-C at 90 d, (P < 0.01) not different at 120 d, and greater for W-C at 150 d (P < 0.01). Additionally, PCV of untreated F-C lambs was lower at 90 d but greater at 120 and 150 d than untreated W-C lambs (P ≤ 0.04). This was the first study conducted in the U.S. to compare longitudinal performance between lambs born in different seasons and reared in different production systems. Under the conditions of this study, organically managed lambs had similar performance to their conventionally managed counterparts. However, large differences in GIN infection risk over time existed between birth seasons and deworming regimens which have important implications for producer management decisions and genetic improvement programs.

The objective of this study was to determine the effects of dietary agro-industrial by-products (AIBP) with different amounts of metabolizable energy (ME) and crude protein (CP) on fermentation (96 h) and gas production (GP) kinetics in vitro, as well as acceptability, animal performance, digestibility, and blood parameters in lambs. The gas production technique (GPT) and fermentation characteristics were used in an in vitro trial. This experiment used diets with ME contents of 6.28, 7.53, and 9.62 MJ/kg, as well as levels 120, 140, and 160 g/kg CP. Principal component analysis (PCA) was used to select the most important dietary ingredient ruminal fermentation parameters. The in vitro results showed that increasing ME and CP content increased and decreased GP (P < 0.05), respectively. An increase in CP content caused an increase in ruminal ammonia nitrogen (NH₃-N) concentration (P < 0.05) and an increase in ME caused a decrease in pH (P < 0.05). PCA, by reducing the dimensions of the variables, shows that neutral detergent fiber (NDF), synchronization index (SI), and lignin as dietary parameters and pH and NH₃ as fermentation quality parameters were the main variables in predicting LWG (P < 0.05). Next, to prove the ineffectiveness of dietary protein content on LWG, the highest ME content (ME = 9.62 MJ/kg) was selected for in vivo experiment. For the in vivo trial, eighteen male lambs of 6-7 months of age and 30.6 ± 2.27 kg body weight were randomly fed on three diets containing 120, 140, and 160 g/kg CP and ME 9.62 MJ/kg. There was no effect of the experimental diets on acceptability, performance characteristics, or apparent digestibility in an in vivo trial (P > 0.05). NH₃-N concentration was affected by the varying content of CP (P < 0.05). The results of this study indicate that Khorasan Kurdish lambs have a high potential for using AIBP in their diet. Additionally, lamb producers can prevent N wastage without worrying about the loss of animal performance by using 120 g/kg CP, which meets the animals' needs and has beneficial environmental consequences.

The snaplage residue presents itself as a potential alternative roughage source in finishing systems, owing to its high fiber concentration which aids in maintaining rumen health. Nevertheless, the performance of animals will hinge on both the allowance and the nutritive value it offers. This study aimed to evaluate different stocking rates of heifers grazing snaplage residue as an exclusive source of fiber on finishing phase performance. The treatments included two stocking rates (SR): i) low stocking rate (LS; 3.5 AU/ha) and ii) high stocking rate (HS; 7.0 AU/ha), which were obtained by modifying the size of the paddocks. Crossbred beef heifers (n = 48; initial body weight = 276 ± 23 kg) were assigned to 16 paddocks (3 heifers/paddock). The concentrate (87% of corn, 3.5% of soybean meal, 3.9% of cottonseed meal, 1.2% of urea, and 4% of mineral; DM basis) was fed ad libitum daily at 0600 hours. Data were analyzed using the MIXED procedure of SAS. There was no SR × time effect (P = 0.88) on residue mass. There was less (P < 0.01) total residue mass for HS than LS, and total mass decreased (P < 0.01) over time. There was no SR × time effect (P ≥ 0.16) for behavior characteristics. There was no difference between HS and LS for average residue intake (P = 0.34; 0.44 vs 0.48 kg/d, respectively), concentrate intake (P = 0.84; 7.72 vs 7.78 kg/d, respectively), and daily gain (ADG; P = 0.94; 0.95 vs 0.95 kg/d, respectively), The HS treatment increased (P < 0.01) gain per area (618 vs 309 kg/ha) compared to LS. No differences between SR were observed for carcass characteristics (P ≥ 0.12). The meat's chemical composition was not different (P ≥ 0.37) between treatments. Overall, the snaplage residue stocking rate did not affect the finishing phase performance of beef heifers, but the greater stocking rate (7.0 AU/ha) increased gain per land area.

The purpose was to determine local (articular) and systemic effects of intra-articular interleukin-1 in horses supplemented with a dietary PUFA supplement [STRUCTURE-Joint (ST-J)]. Sixteen (16) healthy, mature, light breed horses were randomly assigned to diets containing 0 or 120 mL (n = 8 per group) of ST-J for 30 d. On days 0 (prior to beginning supplementation) and 27, recombinant equine interleukin-1β (reIL-1 β) (75 ng) was injected into the left or right intercarpal joint to induce mild, transient synovitis. Synovial fluid was obtained by aseptic arthrocentesis at postinjection hour 0 (immediately prior to IL-1 injection), 6, 12, and 72. ST-J supplementation for 30 d significantly increased synovial fluid nitric oxide, and resolvin D1 compared with the unsupplemented control group and significantly increased PGE₂ levels and reduced joint circumference in the ST-J treated horses on day 30 compared to the same group of horses on day 0. There was also a significant increase in plasma hemoglobin, free and total bilirubin, and decrease in plasma glucose. These data provide evidence for the usefulness of ST-J to modulate physiological variables with importance in exercise performance and tissue adaptation to exercise stress and further research on this product is warranted.

The objective of this study was to evaluate the efficacy of using 3 yeast-based additives as an alternative to sodium monensin on rumen fermentation parameters using a dual-flow continuous fermentation system. Ten fermenters (1,223 ± 21 mL) were used in 2 simultaneous 5 × 5 Latin squares arrangement with 3 periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. Each Latin square assigning either a low or high level of concentrate to beef cattle diets, with 5 specified treatments: Control: no additives; Blend 1: yeast culture (Saccharomyces cerevisiae), beta-glucans, fructooligosaccharides, galactooligosaccharides, and mannanoligosaccharides [1,600 mg/kg dry matter (DM)]; Blend 2: Beta-glucan and mannanoligosaccharide fractions from S. cerevisiae (1,600 mg/kg DM); Yeast Cells: hydrolyzed, inactivated, and spray-dried yeast cells (S. cerevisiae; 2,133 mg/kg DM); monensin (25 mg/kg DM). On days 8, 9, and 10, samples of 500 mL of solid and liquid digesta effluent were mixed, homogenized, and stored at -20 °C. Subsamples of 10 mL were collected for later determination of ammonia nitrogen (NH₃-N) and volatile fatty acids (VFA). Diets with high-concentrate showed higher organic matter (OM) digestibility but lower crude protein and neutral detergent fiber (NDF) digestibilities (P < 0.01). There were no feed additive effects for DM, OM, and NDF digestibilities (P > 0.05). Total VFA concentration and butyrate concentration were higher for the high-concentrate diet (P < 0.01). Conversely, pH and concentrations of acetate and iso-butyrate were higher for the low-concentrate diet (P < 0.01). Treatments with Blend 1, Blend 2, and Yeast Cells had higher VFA concentrations compared to the control (P = 0.04). Blend 1 treatment exhibited higher propionate concentration in fermenters fed with a high-concentrate diet (P < 0.01). In the high-concentrate diet, Blend 1 had a lower acetate: propionate ratio compared to Control, Yeast Cells, and Blend 2 treatments (P < 0.01). The high-concentrate diet showed higher means for all other parameters: Microbial efficiency, N efficiency, N flow, and Bacterial N flow (P < 0.01). Treatments with Blend 2 and Control showed higher rumen undegradable protein N flow compared to Yeast Cells and Blend 1 treatments (P < 0.01). Our findings imply that yeast-based additives might be used as alternatives to monensin, improving ruminal fermentation and promoting enhanced sustainability in livestock.

Yaks are a domesticated species utilized for meat, fiber, and transportation in many countries. In the United States, yak meat is growing in popularity due to its classification as a "healthy" meat. Penetrating captive bolt (PCB) is an approved method of preslaughter stunning and euthanasia for cattle. At the time of our study, peer-reviewed literature or industry guidelines for PCB stunning or euthanasia did not appear to exist for yaks. This study aimed to identify and describe an ideal placement based on the location of the thalamus, part of the brain that is important for sensibility, and to describe the tissue depths at this placement. To do this, 10 hide-on cadaver heads from yaks were sourced from a population of 30 yaks aged 24 to 48 mo, which had a mean hot carcass weight of 180.1 ± 52.0 kg (±SD). Source animals were stunned in a frontal location with a handheld PCB during normal slaughter procedures at the collaborating slaughter establishment. Cadaver heads were stored in a walk-in freezer for 96 d before head processing. Head weight, total head length, horn tip spread, and horn base circumference were measured. Heads were split down the midline using a band saw. Heads were imaged and tissue thicknesses of the exposed surface of each head were measured. Thalamic depth and measurements to describe the location of the thalamus relative to external head anatomy were recorded from these images. Results are reported as mean ± SD. On average, the total length of the head from the poll to the nose was 37.74 ± 2.83 cm. The center of the thalamus was located 11.86 ± 1.32 cm below the poll: 23.88 ± 1.56% down the frontal plane of the head. The exposed diameter of the thalamus on the frontal plane of the head was 3.43 ± 0.31%. Thus, an ideal PCB placement for yaks is located approximately 25% of the way down the frontal plane of the face of the animal. Tissue depth measurements are reported as mean ± SD followed by a 97.5% one-sided upper reference limit (URL). Soft tissue thickness was 16.03 ± 3.26 mm (URL: 23.77 mm), cranial thickness was 30.69 ± 4.34 mm (URL: 40.97 mm), and total tissue thickness was 46.71 ± 7.15 mm (URL: 63.68 mm). Thalamic depth was 92.22 ± 11.60 mm (URL: 119.74 mm). These results show that an ideal PCB placement for yaks is located at 23.88 ± 1.56% of the distance from the poll to the nose down the frontal plane of the head and a penetration depth of 92.22 ± 11.60 mm is required to reach the thalamus.

The varying growth rates within a group of pigs present a significant challenge for the current all-in-all-out systems in the pig industry. This study evaluated the applicability of statistical methods for classifying pigs at risk of growth retardation at different production stages using a robust dataset collected under commercial conditions. Data from 26,749 crossbred pigs (Yorkshire × Landrace) with Duroc at weaning (17 to 27 d), 15,409 pigs at the end of the nursery period (60 to 78 d), and 4996 pigs at slaughter (151 to 161 d) were analyzed under three different cut points (lowest 10%, 20%, and 30% weights) to characterize light animals. Records were randomly split into training and testing sets in a 2:1 ratio, and each training dataset was analyzed using an ordinary least squares approach and three machine learning algorithms (decision tree, random forest, and generalized boosted regression). The classification performance of each analytical approach was evaluated by the area under the curve (AUC). In all production stages and cut points, the random forest and generalized boosted regression models demonstrated superior classification performance, with AUC estimates ranging from 0.772 to 0.861. The parametric linear model also showed acceptable classification performance, with slightly lower AUC estimates ranging from 0.752 to 0.818. In contrast, the single decision tree was categorized as worthless, with AUC estimates between 0.608 and 0.726. Key prediction factors varied across production stages, with birthweight-related factors being most significant at weaning, and weight at previous stages becoming more crucial later in the production cycle. These findings suggest the potential of machine learning algorithms to improve decision-making and efficiency in pig production systems by accurately identifying pigs at risk of growth retardation.

Computer vision techniques are becoming increasingly popular for monitoring pig behavior. For instance, object detection models allow us to detect the presence of pigs, their location, and their posture. The performance of object detection models can be affected by variations in lighting conditions (e.g., intensity, spectrum, and uniformity). Furthermore, lighting conditions can influence pigs' active and resting behavior. In the context of experiments testing different lighting conditions, a detection model was developed to detect the location and postures of group-housed growing-finishing pigs. The objective of this paper is to validate the model developed using YOLOv8 detecting standing, sitting, sternal lying, and lateral lying pigs. Training, validation, and test datasets included annotation of pigs from 10 to 24 wk of age in 10 different light settings; varying in intensity, spectrum, and uniformity. Pig detection was comparable for the different lighting conditions, despite a slightly lower posture agreement for warm light and uneven light distribution, likely due to a less clear contrast between pigs and their background and the presence of shadows. The detection reached a mean average precision (mAP) of 89.4%. Standing was the best-detected posture with the highest precision, sensitivity, and F1 score, while the sensitivity and F1 score of sitting was the lowest. This lower performance resulted from confusion of sitting with sternal lying and standing, as a consequence of the top camera view and a low occurrence of sitting pigs in the annotated dataset. This issue is inherent to pig behavior and could be tackled using data augmentation. Some confusion was reported between types of lying due to occlusion by pen mates or pigs' own bodies, and grouping both types of lying postures resulted in an improvement in the detection (mAP = 97.0%). Therefore, comparing resting postures (both lying types) to active postures could lead to a more reliable interpretation of pigs' behavior. Some detection errors were observed, e.g., two detections for the same pig were generated due to posture uncertainty, dirt on cameras detected as a pig, and undetected pigs due to occlusion. The localization accuracy measured by the intersection over union was higher than 95.5% for 75% of the dataset, meaning that the location of predicted pigs was very close to annotated pigs. Tracking individual pigs revealed challenges with ID changes and switches between pen mates, requiring further work.

A total of 2,268 crossbred pigs (L337 × 1050, PIC; initially 5.5 ± 0.18 kg) were used in a 42-d growth study to evaluate the effects of 1,25(OH)₂D₃-glycoside provided from a plant extract on growth performance, bone characteristics, and serum criteria of nursery pigs. Pigs were weaned at approximately 21 d of age and randomly assigned to 1 of the 3 dietary treatments in a randomized complete block design. A total of 84 pens were used with 27 pigs per pen and 28 replications per treatment with pens blocked by BW and date of entry into the facility. Treatment diets were corn-soybean meal-based and consisted of a control diet (1,653 IU/kg of vitamin D₃), or the control diet with 1.2 or 2.0 μg of 1,25(OH)₂D₃-glycoside/kg. Blood samples were collected from 25 gilts/treatment on days 21 and 42 to assess 25(OH)D₃, cytokine concentrations, and antibody titers. At the end of the study, 10 pigs per treatment were euthanized and the right fibula, metacarpal, second and 10th ribs were collected to determine bone density, breaking strength, and percentage bone ash. Overall, there was a tendency (linear, P = 0.067) for a reduction in G:F as added 1,25(OH)₂D₃-glycoside increased, but no significant effects on final BW, ADG, ADFI, or mortality were observed. There were no treatment × bone interactions for bone breaking strength and bone ash. Percentage bone ash increased (linear, P = 0.030) across all bones as 1,25(OH)₂D₃-glycoside increased. Treatment did not affect bone ash weight and breaking strength. Metacarpals and 10th ribs had the greatest bone ash weight followed by the fibula with the second ribs having the lowest (P < 0.05). Metacarpals had greater breaking strength compared to all other bones, followed by the fibula and 10th rib, with the second rib having the lowest (P < 0.001). There was a bone × treatment interaction for bone density, where increasing 1,25(OH)₂D₃-glycoside increased bone density for the second rib (P = 0.012), but there was no treatment difference for other bones. There was no difference between treatments for antibody titers, 25(OH)D₃ status, or circulating cytokine concentrations except for IL-8 concentrations which decreased (linear, P = 0.037) as 1,25(OH)₂D₃-glycoside increased. In summary, adding 1.2 or 2.0 μg 1,25(OH)₂D₃-glycoside/kg provided from a plant extract to a diet already containing 1,653 IU/kg of vitamin D₃ had no effect on growth or the evaluated serum parameters; however, increasing 1,25(OH)₂D₃-glycoside increased percentage bone ash.