Journal of Animal Science

Hamilton, Emma M; Anderson, Karly N; Kirk, Ashlynn A; Vogel, Kurt D; Grandin, Temple

doi: 10.1093/jas/skaf300.001pmid: N/A

More than 25 million fed cattle are slaughtered each year in the United States. Animal welfare issues associated with hoof abnormalities and congestive heart failure (CHF) have increased, with minimal evaluation of the root cause and methods of mitigation for these issues. Both disorders are deleterious to animal health, welfare, and carcass quality. Our objective was to determine the prevalence of hoof abnormalities and CHF within various physical characteristics. To meet this objective, scorecards for each condition were developed based on existing literature and images from the source population of animals. Scores were recorded at a slaughter establishment in the western region of the United States (elevation: 1,417 m) on cattle < 30 mos of age (N = 398). Statistical analysis was performed to determine the prevalence of each disorder. Further analysis was completed to evaluate the differences between the prevalence of carcass characteristics (USDA quality grade (QG), USDA yield grade (YG), hot carcass weight (HCW), ribeye area (REA), and fat thickness (FT)) within each hoof abnormality or CHF score, as well as the differences between each CHF score within each hoof abnormality. Eighty-five percent of cattle had at least one hoof abnormality, 52% had CHF, and 43% had both. We did not find differences (P > 0.1463) in REA, FT, QG, YG, sex, and hide color across hoof scores. Cattle with a wide toe and inward curved hoof had lighter (P > 0.0258) carcasses (421.62 ± 11.26 kg) than cattle with only an inward curve (460.95 ± 2.92 kg). Cattle with mild CHF had heavier (P = 0.0295) HCW (463.60 ± 3.24 kg) than cattle with no CHF (451.51 ± 3.22 kg). REA for cattle with no CHF was 103.17 ± 0.93 cm2, mild CHF was 104.51 ± 0.88 cm2, and severe CHF was 98.63 ± 2.46 cm2 (P = 0.0711). There were no differences (P > 0.1846) in FT or QG between CHF scores. There was a greater proportion (P = 0.0099) of heifers without CHF (70.97 ± 8.17%) than steers (45.78 ± 2.61%). There was no difference (P > 0.4955) between the presence of CHF within each hoof score. Over half of the cattle in this study had hoof abnormalities, CHF, or both. Data suggested there are developing relationships between CHF score and carcass characteristics including HCW and sex. Further research is required to guide actions to address the animal welfare and productivity concerns associated with these issues.

Gellatly, Desiree; Lei, Yaogeng; Smith, Lyndsey; Edgar, Emilie; Neale, Alison; Bloomfield, Brittany; Elliot, Brianna; Sobrinho, Laio Silva; Baird, Lorna; Thompson, Sean

doi: 10.1093/jas/skaf300.003pmid:

Metallo, Bianca F; Da Selva, Lucas C Spetic; Da Fonseca, Arieli Daieny; Niblett, Richard T; Aviles-Rosa, Edgar O

doi: 10.1093/jas/skaf300.002pmid: N/A

For the past 30 years, research has been conducted to determine the effect of weaning age on piglets’ performance. Nonetheless, the literature is full of contradictory results, and thus there remains no clear consensus on the optimal weaning age. The objective of this study was to evaluate the effect of weaning piglets at 3 and 4 weeks of age (approximately 21 and 28 days) on a set of physiological, behavioral, and performance indicators of welfare, to gain a holistic understanding of the impact of weaning age on piglets’ overall welfare. Sixteen litters were randomly assigned to be weaned at 3 (21-25 days; n=80) or 4 (28-34 days; n=80) weeks of age. At weaning, piglets were blocked by weight and randomly housed in mixed-sex pens of 5 piglets. Blood samples were collected from one focal male and female, per pen, prior to weaning and at 24 hours and 7 days post-weaning to evaluate a treatment effect on blood leukocytes. A subset of pens was video recorded for the first 48 hours post-weaning to evaluate their behavior. Weight gain and feed intake were monitored at 7-, 14-, 21-, and 28-days post-weaning. A series of mixed models were used for statistical analysis. The models included the fixed effects of weaning age, time, and their interaction, and the random effect of pig or pen. Piglets weaned at 3 weeks expressed a higher neutrophil-lymphocyte ratio (3 weeks = 1.93 ± 0.20 SE, 4 weeks = 0.98 ± 0.20 SE; P < 0.001) at 24 hours post-weaning, and less feeding behavior (3 weeks = 0.35 ± 0.08% SE, 4 weeks = 1.34 ± 0.29% SE; P < 0.05) during the first 24 hours post-weaning, compared to piglets weaned at 4 weeks. Overall, piglets weaned at 3 weeks also had lower average daily feed intake (3 weeks = 0.47 (95% CI 0.43, 0.50), 4 weeks = 0.69 (95% CI 0.64, 0.73) kg/day; P < 0.0001) and lower average daily gain (3 weeks = 0.32 (95% CI 0.28, 0.37), 4 weeks = 0.48 (95% CI 0.44, 0.52) kg/day; P < 0.0001) during the 28-day nursery phase. Our results indicate that weaning piglets at 4 weeks of age, as opposed to 3 weeks, has a positive impact not only on their performance, but also on behavioral and physiological indicators of welfare, highlighting the welfare benefits of delaying weaning.

Olatinwo, Omowumi A; Young, Jennifer M; Shevtsova, Tetiana; Voronov, Andriy; Byrd, Christopher J

doi: 10.1093/jas/skaf300.004pmid: N/A

This study evaluated the effect of topical gels containing oleic acid and fish oil on serum-based wound healing indicators in piglets following surgical castration. Fifty-two piglets (3-7 d of age) were randomly assigned to 1 of 6 treatment groups: T1 (sham castration, n = 9); T2 (surgical castration, n = 10); T3 (surgical castration + oleic acid in its natural form, n = 8); T4 (surgical castration + 33% oleic acid gel, n = 8); T5 (surgical castration + 25% oleic acid gel, n = 8); or T6 (surgical castration + 16.5% oleic acid and 16.5% fish oil gel, n = 9). The treatments were topically applied to the incision site immediately after surgical castration. Blood samples collected immediately prior to castration (baseline) and again at +4, +8, +24, +72, and +168 h post-castration were tested for IFN-γ, IL-6, IL-8, and VEGF-α. All data were analyzed using the Proc MIXED procedure in SAS 9.4. No treatment effect was observed for IFN-γ (P > 0.10). Regardless of treatment, IFN-γ did not differ from baseline at any timepoint but was lower at 8h (P = 0.002) and 24h (P = 0.005) compared to 72h (P = 0.304). There was no effect of treatment (P > 0.09) or timepoint (P > 0.05) on IL-6. Similarly, there was no effect of treatment on IL-8 (P > 0.13). However, compared to baseline, IL-8 was lower at 4h (P = 0.001), 8h (P = 0.001), and 24h (P = 0.04) post-castration. Additionally, IL-8 was greater at 168h compared to 4h (P = 0.004), 8h (P = 0.0003), 24h (P = 0.003), and 72h (P = 0.0002) timepoints. There tended to be a treatment effect on VEGF-α (P = 0.08), where T1 exhibited lower VEGF-α concentrations compared to T2 (P = 0.012) and T3 (P = 0.005). Regardless of treatment, VEGF-α was lower at 168h compared to baseline (P = 0.04), 4h (P = 0.03), 8h (P =0.001), and 24h (P = 0.018) timepoints. Additionally, VEGF-α was lower at 72h compared to 4h (P = 0.038) and 8h (P = 0.013) timepoints. In conclusion, topical application of gels containing oleic acid and fish oil did not have an effect on blood-based wound healing indicators following surgical castration.

Joshi, Himani; Prasad, Gagana Sathya Narayana; Bethini, Aravind; McBride, Abigail; McGee, Marcus; Fan, Peixin

doi: 10.1093/jas/skaf300.006pmid: N/A

Lactating dairy cows, including Holstein and Jersey breeds, are particularly vulnerable to heat stress, which elicits distinct behavioral adaptations such as increased respiration, standing duration, decreased feed intake, elevated water consumption, and heightened restlessness. These behavioral responses can significantly compromise animal health, reduce productive efficiency, and impair overall welfare. While these behavioral adaptations serve as critical indicators of heat stress, their detection in real-world cattle herd settings remains challenging and prone to observer bias. Therefore, integration of advanced digital and time-efficient technologies in livestock systems is required to enhance monitoring, reduce handling, and improve welfare perceptions. Machine learning driven computer vision systems are emerging for behavioral monitoring in cattle, yet predictive applications remain limited for lactating cows exhibiting heat stress responses. This study aimed to develop artificial-intelligence-based models using Residual Network-50 Convolutional Neural Networks (ResNet-50-CNN) and You Only Look Once (YOLOv8) to predict differential behavior patterns, during heat stress conditions, among Holstein and Jersey breeds of lactating dairy cows. Twenty-four lactating Holsteins and twelve Jerseys were housed in free stalls during mid-summer (Starkville, Mississippi State, USA) and were provided with ad libitum access to feed and water during a 14-day period. Behavioral observations, i.e., standing, lying, and eating, among Holstein and Jersey lactating cows were captured via twelve stationary ReoLink 5MP PoE IP cameras during four daily intervals (06:00-08:00, 13:00-15:00, 18:00-20:00, and 01:00-03:00), from day 0 to 14, respectively. Raw video footage was processed, and unique frames were extracted at 30-second intervals for each behavior type and annotated for individual animal behaviors i.e. “Standing”, “Lying”, and “Eating”, in each frame using Roboflow software. A total of 1,120 extracted frames (730 for Holstein and 390 for Jersey) were used for training and validation (20%, 100 epochs) using the raw videos from the adaptation days. Additionally, live videos of the four-heat stress (THI>72) trial days were reserved for independent model performance testing. Our trained model, upon validation, showed high accuracy of 0.979 and precision of 0.965 in classifying multi-class behavior in a single frame. When evaluated on unlabeled independent raw videos, it maintained robust performance with an accuracy of 0.892, precision of 0.895, and recall rate of 0.874 in predicting behavior phenotypes and correctly differentiating breed types. Our findings demonstrate that the CNN and YOLOv8 models can effectively distinguish behavior classes and duration across multiple cows and breeds, with promising potential for future applications in detecting heat stress, health indicators, and targeted behavioral traits.

Haggard, Ryne D; Stucke, Rachael M; Varela, Alex; Villard, Allison; Edwards-Callaway, Lily N; Cadaret, Caitlin N

doi: 10.1093/jas/skaf300.005pmid: N/A

Tail docking improves hygiene, reduces flystrike, and enhances efficiency for routine husbandry practices such as shearing, serving as an important management practice that promotes sheep health. However, the procedure is known to cause acute stress and discomfort. Thus, the objective of this study was to evaluate the effectiveness of a lidocaine impregnated band at mitigating pain when tail docking newborn lambs. Thirty-two lambs were randomly assigned to receive a lidocaine impregnated rubber O-ring band (LB; n=16) or a non-medicated standard O-ring band (CON; n=16). An elastrator was used to place CON and LB rings below the third caudal vertebrae for docking lambs at three days of life. At –1h, 0h, 2h, 12h, 24h, 3d, 7d, 14d, 21d, and 28d, behavioral observations, algometry, infrared thermography, and blood collection were performed. From birth to 30d of age, daily weights were collected and used to determine growth and average daily gain (ADG). There was a band by time (P < 0.05) interaction for behavioral response at the time of banding (0h), in which LB lambs exhibited fewer painful behaviors compared to CON. LB lambs had higher (P < 0.05) pressure thresholds above the site of docking compared to CON, while thresholds below the banding site and at the control site did not differ. Thermal imaging revealed no temperature differences between LB and CON lambs at any timepoint or location. There was a treatment by time interaction where LB lambs had decreased (P < 0.05) haptoglobin levels two days post banding compared to CON lambs. First 30d performance did not differ between groups when evaluated as growth or ADG. Length of time until the tail fell off did not differ between treatments. These results indicate that lidocaine bands reduce initial pain response, tissue sensitivity, and resolve the acute phase response faster than traditional bands, minimizing discomfort and stress while still achieving tail docking in the same amount of time. Thus, LBs may serve as a simple tool for livestock producers to incorporate into their standard management practices to enhance animal welfare.

Woiwode, Ruth; Dennis, Elliott J; Akin, Heather

doi: 10.1093/jas/skaf300.007pmid: N/A

Few matters of great societal concern transcend that of a common requirement for food to survive; while everyone eats, a mere 1.36% of the U.S. workforce is employed in agriculture, which includes crop and animal production. The importance of occupational skill has long been recognized, yet attributes of cattle handling skill remain largely unresolved in the literature. For animal caretakers, there is no industry standard defining skill level, and few barriers to entry, such as requisite training. Instead, this sector of the workforce has traditionally relied on self-reported years of experience (YOE), often gained growing up on a farm or ranch, as a proxy for skill. When 50% of the population was involved in agriculture, this may have been a realistic prerequisite, but for modern agriculture, the assumption that familiarity with agriculture is a prerequisite can be deadly. While fatal injuries in crop production decline, fatal injuries steadily increase for animal workers, despite adoption of technology by both sectors. The relationship between skill level of cattle handlers and risk for injury has not been well described in the literature. We compared self-reported YOE, self-rated expertise, and self-reported scores for ten cattle handling tasks with independently assigned scores, and investigated the relationship between demographic information, prior injury history, self-reported measures, and expert assessment of skill level. A panel of experts identified ten tasks intended to be representative of a core skill set used by workers across sectors of the cattle industry. Each task included categories reflecting attributes of skill believed to be important for both animal welfare and handler safety. The skill assessment tool (SAT) developed by the panel was used to evaluate 15 participants of varied backgrounds. Participants were asked to report experience in number of years for all major livestock species; all reported ≥5 YOE. Participants were asked about prior injuries; seven reported no previous injuries; eight reported previous injuries sustained working with livestock. Participants completed 10 tasks with a group of cattle and were asked to score their own performance for each task. Classroom training covering principles of low-stress cattle handling was provided between handling trials. Following the training, participants repeated the cattle handling tasks and again scored themselves. The same expert was present to score all handling trials live. Video recordings were used post-hoc to validate live scores. Demographic information and self-reported scores were compared to expert-assigned scores, and the SAT was sensitive enough to detect differences in skill level between participants for both self-reported and expert-assessed scores. Male participants scored themselves higher than females, and all participants scored themselves higher than the expert. No differences were observed for self-reported or expert assigned scores before or after the training, suggesting this approach to training has limited efficacy.

Webberson, Emily M; Garcia, Arlene; Aviles-Rosa, Edgar O

doi: 10.1093/jas/skaf300.008pmid: N/A

An increase in aggressive behaviors is observed when unfamiliar breeding-age gilts are mixed. High incidence of aggression can lead to injuries and ultimately affect gilts’ longevity, reproductive performance, and welfare. Research has found that environmental enrichment in the form of toys can help redirect undesired behaviors. However, gilts’ preference for enrichment toys of varying size, location, and food additives with the potential to reduce aggression when breeding-age gilts are mixed has not been thoroughly studied. The objective of this study was to assess breeding-age gilts’ preference for different enrichment objects. In Experiment 1 and 2, we evaluated gilts (N=32) preference for 3 different toys (Jolly Ball, Kong, Ring ball) at different locations (floor, hanging) and either alone or with a food additive (applesauce, peanut butter). Each combination of toy, location, and food was tested individually and in random order, and gilts’ behavior was recorded for 5 hours to measure interaction time. Experiment 1 showed gilts interacted significantly more with toys on the floor (4.9%, 95% CI [3.9%, 6.2%]) than hanging (3.1%, 95% CI [2.4%, 4.0%]) (p< 0.0001). The results also showed a statistical significant interaction where gilts interacted significantly more with Jolly Balls on the floor (5.3%, 95% CI [4.1%, 6.8%]), and Kongs on the floor (5.1%, 95% CI (4.0%, 6.5%]) and hanging (4.5%, 95% CI (3.5%, 5.8%]), than any other combination of toy and location (p<0.0001). A statistically significant 3-way interaction between location, toy, and food was observed in Experiment 2 (p=0.02). Overall, gilts interacted with the Jolly Ball on the floor filled with applesauce (7.9%, 95% CI [6.6%, 9.4%]) or peanut butter (8.9%, 95% CI [7.5%, 10.5%]) more than any other permutation of food, toy, and location. We are currently evaluating if providing the Jolly Ball filled with applesauce on the floor reduces the incidence of aggression when breeding-age gilts are mixed. Our work will provide insight as to enrichment that can be utilized to potentially reduce aggression in breeding-age gilts and thus improve gilt welfare and longevity.

Davis, Noah; Wyffels, Sam; Carr, Craig; Nugent, Paul; DelCurto, Tim

doi: 10.1093/jas/skaf300.009pmid: N/A

Foraging animals select for resources across spatial scales, however, information quantifying this is limited for livestock species. Therefore, this study evaluated the relative selection for resources across multiple spatial scales. Over the course of two winters, a herd of 140 mature, Angus-based cows grazed a 645-ha native rangeland pasture in southwestern Montana. Each winter, 17 cows were randomly selected and equipped with global positioning system (GPS) collars and monitored between December and February. For each animal, we generated a utilization distribution using GPS locations identified as occurring during grazing activity. We obtained gridded, 30-m resolution data on pasture attributes, including topography (elevation, slope, terrain roughness, aspect), vegetation (cover and biomass by plant functional group), and distances to water and supplement sites. To create coarser-scale data for each attribute, we used a moving window to calculate the mean value up to a 1000 m neighborhood size for each cell of the grid. Then, for each metric, we built a multi-level resource utilization function that calculated the selection coefficient for each animal at each scale. To evaluate how population-level selection varies across scales, we analyzed selection coefficients with a set of candidate linear mixed-effect models. Of the 18 attributes evaluated, 17 showed a significant relationship between scale and resource selection (P ≤ 0.03). Fourteen of the attributes indicated strongest support for a second- or third-order quadratic relationship. The remaining four showed strongest support for a linear relationship. Cows selected against the topographical attributes of elevation, slope and terrain ruggedness across all scales (P < 0.01) and most strongly at coarser scales (620-1000 m resolution). Additionally, cows selected for directional components of aspect at coarser scales (780-1000 m resolution; P < 0.01). Cows selected for annual and perennial herbaceous cover at fine scales (30-110 m resolution; P < 0.01). Cows selected against bare ground, litter, and tree cover across all scales and (P < 0.01) most strongly at the coarsest scale considered (1000 m). Cows most strongly selected for perennial herbaceous biomass at the finest scale considered (30 m; P < 0.01) and for annual herbaceous biomass at a moderate scale (620 m; P < 0.01). Cows selected against distance from water and supplement across all scales (P < 0.01). The intraclass correlation coefficient (ICC) was highest for distance attributes (ICC = 0.99), followed by topographical attributes (ICC = 0.45), and lowest for vegetation attributes (ICC = 0.23), indicating that selection for vegetation attributes was more consistent among individuals, whereas selection for distance attributes was least consistent. This information provides insight for rangeland scientists and livestock managers to inform the development of resource use models and evaluate the effective scale for various rangeland improvements.

Li, Yuzhi; Archer, Courtney A; Anderson, Jon; Schmidt, Ty B; Mote, Benny E; Johnston, Lee J

doi: 10.1093/jas/skaf300.010pmid: N/A

Understanding the dynamics of tail biting in pigs, such as which pigs are involved and what roles these pigs play in this damaging behavior, can help us develop management strategies to minimize tail biting outbreaks. We evaluated social structures and positions of pigs involved in tail biting outbreaks (TBO) using social network analysis. Pigs (n=252, initial weight=28.9±3.4 kg) with intact tails were grouped (7 pigs/pen, 36 pens) based on litter origins (littermates, half-group littermates, non-littermates). Pigs were housed in barns with slatted floors (0.98m2/pig) for 12 weeks until market weight (123.1±11.9 kg). Behavior of pigs was recorded continuously using the NUtrack Livestock Monitoring System. Tail injury was evaluated weekly to monitor TBO. Thirteen pens (littermates=3 pens, half-littermates=5 pens, and non-littermates=5 pens) experienced TBO in which at least one pig in a pen had blood on the tail caused by tail biting. Videos for these pens, recorded the day before and during the first TBO, were manually reviewed to document tail biting events and identify the roles of the pigs involved. The top 25% of pigs responsible for the most tail-biting incidents were classified as tail-biters and others as non-biters. Network metrics were calculated using RStudio. Data were analyzed using Glimmix and NPAR1WAY procedures. No difference in network metrics at the pen-level (all P ≥ 0.128; Table 1) was detected among litter origins. Average density ranged from 0.27 to 0.33, indicating that 27 to 33% of possible pairs (dyads) of pigs engaged in tail biting. Among these pairs, 17 to 37% (reciprocity) were biting each other. Out-, in- and all-degree centralizations were closer to 0 than 1, indicating that tail biting was not performed mainly or received by few pigs. At the pig-level, no difference was detected in unweighted or weighted centralities among litter origins (all P ≥ 0.32). Compared to non-biters, tail-biters had greater unweighted out-degree, closeness, and betweenness, and greater weighted out-edge strength and betweenness centralities (all P ≤ 0.04, Table 2), indicating that tail-biters bit more pigs, were more connected to other tail-biters, and committed more tail biting events. No difference was detected in unweighted in-degree, weighted in-edge strength, out- and in-closeness centralities between tail-biters and non-biters. Both tail-biters and non-biters were bitten about 3 times (in-edge strength) by 1.76 pigs (unweighted in-degree centrality) on average, suggesting that tail-biters were bitten as often as non-biters. Gilts tended to have greater (all P ≤ 0.08) unweighted closeness and betweenness, weighted out-edge strength and betweenness centralities than barrows, suggesting that gilts were more closely connected with other pigs that were involved in tail biting and performed more tail biting than barrows. These results demonstrate that social network analysis can provide insight into the dynamics of tail biting among pigs.