Translational Animal Science最新文献

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.

Various pet food diet formats are available, but many are poorly studied. The objective of this study was to determine the apparent total tract macronutrient digestibility (ATTD) of frozen raw, freeze-dried raw, fresh, and extruded dog foods and assess their effects on serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Ten beagle dogs (4.10 ± 0.74 yr) were used in a replicated 5 × 5 Latin square study to test the following diets: Chicken and Barley Recipe (extruded; Hill's Science Diet [EXT]), Chicken and White Rice Recipe (fresh; Just Food for Dogs [FRSH]), Chicken Formula (frozen raw; Primal [FRZN]), Chicken and Sorghum Hybrid Freeze-dried Formula (freeze-dried raw; Primal [HFD]), and Chicken Dinner Patties (freeze-dried raw; Stella & Chewy's [FD]). The experiment was composed of five 35-d periods, with each ending with fecal and blood collections. Data were analyzed using Mixed Models in SAS 9.4, with P < 0.05 being significant. Treatment was a fixed effect and dog a random effect. Protein ATTD was higher for FRZN and FD than other diets and higher for HFD than FRSH and EXT. Fat ATTD was higher for HFD than FRZN and EXT and lower for EXT than other diets. Fecal output was higher for dogs fed EXT than those fed other diets and higher for dogs fed FRSH than those fed FRZN, HFD, or FD. Fecal pH was lower in dogs fed EXT and FRSH than those fed other diets. Fecal scores were higher (looser) in dogs fed EXT and FRSH than those fed FRZN and FD. Fecal dry matter was higher in dogs fed FD than those fed other diets and higher in those fed FRZN and HFD than those fed EXT and FRSH. In general, fecal short-chain fatty acids were highest in dogs fed EXT, intermediate in dogs fed FRSH and HFD, and lowest in dogs fed FRZN and FD. Fecal isobutyrate and isovalerate were highest in dogs fed HFD, lowest in dogs fed FRSH, and intermediate in dogs fed other diets. Fecal primary bile acids were higher, while secondary bile acids were lower in dogs fed FRSH than in dogs fed other diets. Fecal microbiota were greatly impacted by diet, with alpha diversity, beta diversity, and relative abundances of over 40 bacterial genera being different among treatments. This study shows that dietary format may lead to great differences in nutrient digestibility and fecal characteristics, metabolites, and microbiota. More research is needed to distinguish the effects of ingredient source, processing method, and nutrient composition.

Experiments were conducted during the summers of 2021 and 2022 to evaluate the effects of feeding strategy and shade on growth performance, animal comfort, water usage, apparent diet digestibility, and ruminal fermentation characteristics of growing heifers during periods of heat stress. In Exp. 1, 852 heifers (initial body weight [BW] = 251 ± 13 kg) were assigned to one of 4 treatments: high-energy diet limit-fed at 2.2% of BW (dry matter [DM] basis; LIM) or high-roughage diet fed for ad libitum intake (ADLIB) with shade (SH) or without shade (NSH). Pen BWs were measured on day 0, weekly from days 14 to 84, day 90, and day 97. Pen weights were used to adjust weekly intakes of LIM. Refusals for ADLIB were targeted at 5% of feed consumed the previous day. Following the 90-d feeding period, a gut-fill equilibration diet was fed to all cattle at 2.5% of BW (DM basis) for 7 d to balance differences in gut-fill between dietary treatments. Dry matter intake was lesser (P < 0.01) for LIM compared with ADLIB. Average daily gain (ADG) and gain:feed (G:F) were greater (P < 0.01) for LIM compared with ADLIB. In addition, ADG and G:F were greater (P < 0.01) for SH compared with NSH. Water usage was less (P < 0.01) for SH heifers compared with NSH and was also less (P < 0.01) for LIM compared with ADLIB. Mean panting scores were lower (P < 0.01) for SH compared with NSH and LIM compared with ADLIB. In Exp. 2, 16 heifers (initial BW = 254 ± 22 kg) were arranged in 4 replicated 4 × 4 Latin squares to evaluate treatments from Exp. 1. Apparent total tract digestibility of DM and organic matter was greater (P < 0.01) for LIM compared with ADLIB. Ruminal pH was more acidic (P = 0.02) for LIM compared with ADLIB. Shade did not affect (P ≥ 0.68) apparent diet digestibility; however, ruminal pH was greater (P < 0.01) for SH compared with NSH. In conclusion, LIM improved feed efficiency, reduced mean panting score, and reduced water usage compared with ADLIB. In addition, SH improved growth performance, reduced water usage, and improved animal comfort during periods of heat stress.

Strip grazing can increase forage utilization, though it has been shown to decrease individual animal performance. The objective of this study was to evaluate forage utilization and cattle performance when strip grazing (STRIP) vs. continuously grazing (CONT) stockpiled annual forages. Experiment 1 consisted of a mix of Jerry oats (Avena sativa) and Trophy rapeseed (Brassica napus) while experiment 2 was a 17-species mix in which the forage mass was predominantly pearl millet (Pennisetum glaucum), German millet (Setaria italica), and browntop millet (Urochloa ramosa). Fields were divided into six 6.3-ha (experiment 1) or 4.1-ha (experiment 2) paddocks which were blocked by location. Treatment was randomly assigned within block (n = 3 replicates per treatment per experiment). Grazing was initiated in November and terminated in February. This resulted in a total of 83 and 54 grazing days for experiments 1 and 2, respectively. Forage was allocated to STRIP twice a week. The STRIP steers gained 16% less (P = 0.01) per day in experiment 1, but in experiment 2, there was no difference (P = 0.56) between treatments. Compared to CONT, the carrying capacity (AUM/ha) of STRIP was increased (P = 0.03) by 81% in experiment 1 and tended to increase (P = 0.10) in experiment 2. Gain per hectare increased (P = 0.02) for STRIP by 56% in experiment 1 and by 31% in experiment 2. Strip grazing stockpiled annual forages can be an effective way to increase carrying capacity and gain per hectare during the fall and winter months but effects on individual animal performance are inconsistent. Disparities in response to strip grazing could stem from differences in forage quality and allocation. Further research is needed to refine and optimize the utilization of this management approach.

Animal welfare is a global issue. The ability of our future workforce to solve global issues is contingent on their understanding of and ability to work with people from diverse cultural backgrounds. Study abroad programming can improve cross-cultural abilities of participating students. Therefore, study abroad opportunities in animal welfare education may be a particularly fruitful approach for preparing students to address animal welfare issues globally. We discuss the value of offering study abroad courses in animal welfare, detail one such course as a case study, and review pedagogical literature related to course design to guide the development of similar programs.

Dried distiller grains with solubles (DDGS) are a popular byproduct used in the livestock feed industry as it is a cost-effective feedstuff that is rich in crude protein and minerals. However, a common concern related to the use of DDGS in livestock diets is the negative impact that affects animal dry matter intake (DMI) and growth. To further investigate this challenge, the experiments aimed to evaluate the effect of feeding 1) two different diets, control versus heat processed DDGS or 2) increasing the concentration of DDGS and its effect on body weight (BW), average daily gain (ADG), DMI, and gain to feed ratio (G:F) in finishing lambs. In experiment 1, both diets were the same except for the heat processing of DDGS; the control diet used a commercial DDGS source directly from the supplier and the processed diet contained the same commercial DDGS source that differed through additional heat processing. For DDGS heat processing, 40% moisture was added to the DDGS and heated at 150 °C for 70 min. After the heating process, the DDGS was placed in a second oven at 56 °C for 2 d to allow for humidity evaporation. Lambs (n = 34), blocked by sex and BW, were housed in pens (2 to 3 lambs/pen, 6 pens/treatment) and were fed for 42 d. Lamb DMI was measured daily, and BW was measured every 14 d. In experiment 2, lambs (n = 75) were blocked by BW (5 lambs/ pen, 5 pens/treatment) and fed diets differing in inclusion rates of DDGS (10%, 20%, and 30%). The feeding period lasted for 56 d, and lamb DMI and BW were measured daily or every 28 d, respectively. In both experiments, diets were isonitrogenous, and the feeding procedure utilized slick bunk management. Data were analyzed in SAS using a mixed model considering the treatments as fixed effects and pen and block as random effects. In experiment 1, there were no treatment differences (P ≥ 0.13) in ADG, DMI, and G:F in finishing lambs. In experiment 2, a linear and quadratic contrast were used to separate the mean and demonstrated that increasing the concentration of DDGS decreased lamb DMI (linear P < 0.01; quadratic P = 0.05), but did not affect lamb BW, ADG, or G:F (P ≥ 0.26). Despite that previous research shows differences in animal growth because of an increase in DDGS concentration, our experiments illustrated that heat processing or increased concentrations of DDGS up to 30% in finishing lamb diets are not responsible for a decrease in lamb performance.

Concerns have been raised about the prevalence of anemia in sows, yet our understanding of its consequences, particularly its impact on the farrowing process, remains limited. This study investigated the relationship between hemoglobin concentration (HbC) and farrowing duration in sows. A total of 101 sows (n = 16 parity 0, 15 parity 1, 24 parity 2, and 46 parity 3 sows) were monitored for blood HbC (Hemocue Hb 201 device) from the ear vein before farrowing (day 112 of gestation) and between 40 to 48 h after farrowing (day 2). Sows were categorized as anemic (HbC < 10 g/dL), or nonanemic (HbC ≥ 10 g/dL) based on their day 112 HbC (i.e., prefarrowing status). Surveillance cameras recorded the farrowing process for each sow, complemented by human observation. Farrowing duration was defined as the time elapsed between the first piglet born and the last piglet born. All piglets were individually weighed within 18 h of birth, and stillborn piglets were identified using a lung flotation test conducted within 1 h of birth. The correlation between sow HbC, farrowing duration, and stillborn piglets was assessed using the PROC CORR procedure in SAS. Additionally, the effect of HbC category on labor duration was tested using the PROC MIXED procedure, with total piglets born included as a covariate. Anemic sows had a prolonged farrowing (7.2 h ± 0.92 min, P < 0.001) compared to nonanemic sows (3.5 h ± 0.88 min), and negative correlation was observed between prefarrow HbC and farrowing duration (r = -0.62, P < 0.001). There was a weak correlation between farrowing duration and stillborn piglets (r = 0.32, P = 0.01). No correlation was observed between farrowing duration and total born (r = 0.22, P = 0.11). There was no difference in total born (16.41 ± 0.7 vs 16.3 ± 0.7) between anemic (< 10 g/dL) and nonanemic (≥10 g/dL) sows, respectively. Factors such as barn temperature on the day of parturition and feed intake the day prior did not influence the observed differences in labor duration between anemic and nonanemic sows. In conclusion, maintaining HbC above 10 g/dL appears beneficial for sows, as lower concentrations of HbC are associated with prolonged labor and increased removal rates. Blood HbC could serve as a valuable biomarker for identifying at-risk sows, thereby aiding in improving herd management and productivity.