bluuebunny/crossref_metadata_2025 huggingface dataset:
127 Effects of maternal pre- and post-partum supplementation of a Bacillus-based DFM on plasma metabolome profile of Bos indicus-influenced heifers and their offspring
Authors: Izquierdo Vinicius S , Cappellozza Bruno I , Gonella-Diaza Angela M , Ashrafi Nadia , Mimi Romana A , Graham Stewart F , Vendramini Joao M B , Moriel Philipe
Published: September 2024

This study evaluated the effects of maternal supplementation during pre- and postpartum of a Bacillus-based direct-fed microbial (DFM) on plasma metabolome of Bos indicus-influenced cow-calf pairs. On d 0, 72 pregnant Brangus crossbred beef heifers (20 to 22 mo of age) were stratified by their initial body weight (BW; 431 ± 31 kg) and body condition score (BCS; 6.0 ± 0.36), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and 6 heifers/pasture). Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of heifers supplemented with 1 kg/d of soybean hulls dry matter added (BAC) or not (CON) with a Bacillus-based DFM mixture (Bovacillus; Chr. Hansen A/S, Hørsholm, Denmark) from d 0 to 242 (139 ± 4 d prepartum to 104 ± 4 d postpartum). Calves were weaned on d 242 (96 ± 30 d of age) and then allocated into 1 of 12 drylot pens and limit-fed the same concentrate at 3.25% of BW until day 319. On d 271 and 287, calves were vaccinated against pathogens associated with bovine respiratory disease and Clostridium. Blood samples were collected from all heifers on d 0 and 63 and from all calves on d 271, 274, and 287 to determine the plasma concentration of metabolites using liquid chromatography. The PLS-DA revealed a clear separation of plasma metabolome profile of BAC and CON heifers and offspring. For the heifer metabolome, 66.5% of the treatment separation on d 63 was explained using 3 components (R2 = 0.96), and BAC heifers had increased (P ≤ 0.05) plasma concentration of 17 metabolites, including phosphatidylcholines and amino acids related classes, but decreased (P ≤ 0.05) plasma concentration of 4 metabolites from triglycerides class compared with CON heifers. For the calf metabolome, 45.6 (R2 = 0.95), 56.7 (R2 = 0.95), and 61.3% (R2 = 0.99) of the treatment separation on d 271, 274, and 287, respectively, were explained using 3 components. Plasma concentrations of 9, 10, and 28 metabolites associated with protein and fatty acid metabolism increased (P ≤ 0.05) in BAC vs. CON calves on d 271, 274, and 287, respectively. Compared with CON, BAC calves had increased (P ≤ 0.05) concentration of metabolites from phosphatidylcholines class all days, from amino acids related class on d 274 and 287, and from triglycerides class on d 287. Plasma concentrations of 3 and 6 metabolites from triglycerides class decreased (P ≤ 0.05) in BAC vs. CON calves on d 271 and 274, respectively. Thus, maternal supplementation of Bacillus-based DFM altered the plasma metabolome of heifers and their calves, leading to increased plasma concentrations of phosphatidylcholine and amino acids related classes in heifers and calves, but fluctuating effects on triglycerides class concentrations in calves.
156 Probiotics (direct fed microbials) and feed efficiency in dairy cows
Authors: Bach Alex
Published: September 2024

Enhancing feed efficiency in dairy cattle is important because on one side it improves the utilization of natural resources, and thus reduces the environmental impact to produce milk; and on the other it may contribute to improve economic returns. Key factors modulating feed efficiency of cows include the fermentation process in the rumen as well as the digestion in both the small and large intestines, but also the way nutrients are metabolized and diverted to different body functions. These four aspects are influenced by the type and amounts of dietary nutrients, which in turn influence the rumen, as well as intestinal microbiomes. These four aspects can also be modulated by probiotics. Probiotics are defined as “live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host”, but a better word for this type of microorganisms is “direct fed microbials” (DFM), as they can confer benefits not associated to heath. Most DFM for dairy cows have focused on the rumen (to foster fiber degradation or reduce risk of rumen acidosis) and have mainly been yeast-based. But there is a poorly explored opportunity to use bacterial and also fungal DFM targeting not only the rumen but also the small and large intestines. Some DFM have been shown to modify nutrient digestion, pH of the digesta, and alter the microbiome and the metabolites it produces. However, inconclusive results are reported in the literature, mainly due to the type of DFM supplemented and the lack of a holistic approach to understand the potential alteration in the dynamics of the entire digestive microbiome. Microbes in the digestive system have a role in degrading some of the nutrients, but they also interact with the intestinal epithelium, altering its absorptive capacity, and may exert an effect in the metabolism of the gut wall, and even influence the metabolism of the host. Modifications in the digestive microbiome elicited by some DFM have resulted in drastic changes in gene expression in whole blood from cows. These changes in the gut microbiome may also facilitate rapid fluctuations in the metabolism of the host and help the cow to adapt to sudden environmental changes, such as heat waves. Many studies using DFM have focused on milk yield, with fewer evaluating consequences on feed efficiency and digestive function. Some DFM may play a role on methane returns to the environment by modulating hydrogen fate in both the rumen and hindgut, and these DFM may also have potential to increase feed efficiency as more carbons could be potentially retained in the digesta. A summary of current state-of-the-art will be provided along with possible future directions and opportunities with DFM in dairy cows.
150 Supplementing Bovacillus to high-risk cattle during a 90-d grazing period
Authors: Cooke Reinaldo F , Mackey Shea , Pickett Autumn , Harvey Kelsey M , Karisch Brandi B , Cappellozza Bruno I
Published: September 2024

This experiment compared performance, health, and physiological responses of high-risk beef cattle receiving a Bacillus-based probiotic during a 90-d grazing period in a study replicated over 2 yr. Angus-influenced steers (n = 120/yr) were obtained from an auction yard and transported to the experimental facility (150 km). Steer body weight (BW) was recorded at arrival (d -1), and this value was averaged with BW recorded on d 0 to represent initial BW (236.6 ± 1.5 kg). On d 0, steers were ranked by BW and allocated to 1 of 12 pastures (4-ha pastures; 10 steers/pasture). Pastures were randomly assigned to receive daily supplementation with dried distillers grains at 1% of BW containing either: 1) Bacillus subtilis and B. licheniformis ingredient (BOV; 2 g/steer daily of Bovacillus; Novonesis, Horsholm, Denmark) or 2) no additive (CON). Cattle received treatments from d 0 to 90 while housed in pastures containing stockpiled native grass forage, as well as free-choice access to water and a commercial mineral + vitamin mix without ionophores. Steers were assessed for bovine respiratory disease (BRD) signs daily. Blood samples were collected, and BW recorded on d 0, 14, 28, 56, and 90. Shrunk BW was recorded on d 91 for average daily gain calculation. No treatment differences were detected (P ≥ 0.36) for glucose, non-esterified fatty acids, β-hydroxybutyrate, insulin-like growth factor-1, or plasma concentrations of antibodies against BRD viruses. A treatment × day interaction was detected (P ≤ 0.05) for plasma haptoglobin concentration, which was greater for CON steers on d 14 and 28 (P ≤ 0.02). Although BRD incidence response lacked treatment differences (P = 0.97), steer mortality and removals for health complications were greater in CON compared with BOV steers (0.00 vs 5.04 %; P = 0.01). Body weight and average daily gain were not impacted by BOV supplementation (P ≥ 0.73). Total BW gain per pasture was greater in BOV compared with CON (643 vs. 496 kg BW change/pen; P = 0.02). Overall profit per pasture was increased in BOV steers compared with CON ($29.1 vs $-330; P = 0.03) resulting in a return on investment of 33:1 over the 90-d experimental grazing period. Despite lacking difference for incidences of BRD or most physiological responses, an increased number of BOV steers completed the trial. Hence, supplementation with a probiotic based on B. subtilis and B. licheniformis to high-risk beef steers increased overall production liveweight and investment return during a 90-d grazing period.
179 Charting the evolution of rumen microbial models from past to present
Authors: Tedeschi Luis O , Adams Jordan M , Lee Mingyung , O’Reilly Keara , Guarnido-Lopez Pablo , Batista Luiz Fernando Dias
Published: September 2024

This review delves into the intricate realm of ruminal microbes, shedding light on their complexity beyond previously recognized dimensions. Existing publications have probed the essential facets of these microorganisms on a finer scale than previously acknowledged. Mathematical models have emerged to simulate the behavior of approximately 200 distinct bacterial species, 25 genera of ciliate protozoa, and five genera of anaerobic fungi, constituting about 10% of the total viable bacteria in the rumen. However, the expansive diversity and density of rumen microbes challenge the complete characterization of species or genera in relation to substrates or end products. Consequently, continuous revision and re-engineering of mathematical models become imperative. In the context of ruminants, prevalent models often categorize bacteria into fiber-fermenting and nonfiber-fermenting groups. An additional subgroup featuring hyper-ammonia-producing bacteria has been proposed, but its explicit integration into nutrition models remains unexplored. Furthermore, incorporating a more mechanistic evaluation of protozoa and fungal growth may be warranted to improve nutrition models. The time horizon and intervals at which models are constructed present another critical consideration, with feed efficiency variations among ruminants believed to be closely tied to differences in the ruminal microbiota. Addressing immediate concerns, this review underscores the need for a comprehensive exploration of factors influencing microbial growth in the rumen. Several indices have been suggested and adopted to predict microbial efficiencies, but they may provide simplification for practical application. Thus, a mechanistic approach should be considered to remove dependencies between estimates and improve predictive accuracy and precision. While artificial intelligence holds promise in elucidating gaps within empirical and mechanistic models, the generation of accurate, vetted datasets is paramount. Furthermore, this review posits that factors such as recycled nitrogen, endotoxins, and microbial population dynamics (i.e., cross-feeding and competition) may be limiting our understanding of microbial growth, suggesting the necessity of modeling these intricacies concurrently to achieve a more nuanced comprehension. This multifaceted approach aims to propel the understanding of ruminal microbial dynamics into new frontiers, paving the way for more informed and effective modeling in the future.
206 Effects of breed type and days on trial on feeding behavior in growing goats fed a total mixed diets using GrowSafe feeding technology
Authors: Kidane Negusse F , Irvin MerricK E , Foxworth William B , Carstens Gordon E , Horner Scott D , O’Reilly Keara
Published: September 2024

The objective of this study was to evaluate the effects of breed and days on trial (DOT) on feeding behavior traits in two breeds of growing goats. Nineteen female goats [n = 10 Alpine; n = 9 Spanish, with average initial ages of 360 d and 352 d, and body weight (BW) of 38.8 ± 2.8 kg and 35.5 ± 3.1 kg, respectively], were randomly assigned within the breed to one of two non-adjacent pens (5 goats/pen), each equipped with GrowSafe feed bunks. A pelletized total mixed ration (TMR) was fed twice per day and goats had ad libitum access to feed, water, and mineral block throughout the 84-d trial. Feeding behavior traits, including feed intake, bunk visit frequency (BVF), head-down duration (HDD), and dry matter intake (DMI) were collected daily using the GrowSafe feeding system. A 14-d interval was used to derive feed behavior traits of individual goats at 42, 56, 70, and 84 DOT. Data were analyzed using a repeated-measures model with a fixed effect of breed, DOT as a repeated measure, and breed x DOT interaction with pen as a random effect. Alpine goats had greater (P < 0.05) initial and final BW (37.6 kg and 51.7 kg, respectively) than Spanish goats (34.7 kg and 46.5 kg, respectively) although DMI (P = 0.10; 1.73 ± 0.31 and 1.39 ± 0.18 kg/d) did not differ. There was not a significant difference (P > 0.05) between breeds for frequency of bunk visits (21.1 vs. 18.6) and bunk duration (P > 0.05). Similarly, the effect of breed on DMI (27.1g/min vs. 22.8 g/min) was non-significant (P > 0.05). Furthermore, breed did not significantly (P > 0.05) affect HDD (31.3 min/d vs 31.9 min/d). However, there was a significant interaction (P < 0.05) between breed and DOT for HDD. In addition, significant differences (P < 0.05) were observed due to the length of DOT for BVD, bunk visit duration, HDD, and eating rate (g/min). Our results suggest that Spanish goats tended to visit feed bunks more frequently per day and tended to consume less feed per visit than their counterpart Alpine goats, and the feeding behaviors of goats change with age. However, further research is warranted to determine changes in the feeding behavior of goats in different production cycles.
208 Assessment of a new oral neonatal supplement for lambs
Authors: Ralston Brenda J , Hanson Andrea M , Nagel Denis , Beaugrand Kendall , Schatz Crystal , Ross Joe , Olson Merle , Allan Nick
Published: September 2024

The objective of this study was to evaluate an easy to administer and economical oral nutritional supplement for neonatal lambs. Neonates are at risk of nutrient deficiencies because of maternal deficiencies, minimal body stores at birth and decreased nutritional intake. The pre-ruminant lamb relies solely on milk for adequate immunity and nutrition until they begin ingesting forages. Insufficiencies can lead to increased mortality and morbidity. However, deficiencies in the ewe are common due to variation in management, feeding and health protocols. A total of 10 lambs (5 sets of twins) were enrolled into the study. The lambs were divided into two groups (one twin from each set) received a treatment of an oral vitamin-mineral supplement (VitaFerst-Care) 3 mL and the control lambs a saline solution of 3 mL, all at 3 d of age (d0). Blood samples were collected, prior to, and again following supplementation (d 0, d 21) by jugular venipuncture. Vitamin A, vitamin E, iron (Fe) and selenium (Se) concentrations were determined in blood serum/plasma of the lambs by HPLC. Kidney and liver function markers were analyzed using HESKA DC5X veterinary analyzer to confirm the safety of the supplement. Variables tested included alkaline phosphatase (ALP), alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine (CREA), glucose (GLU), total protein (TP), total bilirubin (T-BILI), albumin (ALB), phosphorus (PHOS), calcium (CA), cholesterol (CHOL), and gamma-glutamyl transferase (GGT). All lambs remained with their mothers. The average difference was calculated between d 21 and d 0 (baseline) for treated versus control animals for vitamin A, vitamin E, Se, and Fe. Significance was calculated using a two-tailed student’s t-test where P < 0.10 between d 21 control and treated animals. Control animals had an average vitamin E plasma concentration of 1.168 + 0.355 ppm on d 21, whereas treated animals had an average of 1.547 + 0.559 ppm. Significance was calculated at P = 0.09. Vitamin A, Fe and Se concentrations did not reach significance. Kidney and liver panel checks for animals in each group were not concerning. Future studies should look at modifying first and second sampling timepoints to be closer together. Based on results in calves with a similar study design, shortening the time between treatment and second sampling would give a clearer picture of how the neonatal supplement influenced the nutritional status of the treatment versus control animals.
215 Tracking growth performance and insulin response on four-month-old maternal heat-stressed lambs
Authors: Rios Andrea P , Fuentevilla Ela , Diaz Duarte E , Limesand Sean
Published: September 2024

Poor growth performance and metabolic disorders are prevalent problems in lambs exposed to maternal heat stress, specifically during the last mid-third of gestation. Columbia–Rambouillet crossbred lambs (n = 12) were immediately separated from their heat-stressed and non-stressed dam at lambing. The maternal heat stress exposure occurred during the last mid-third gestation and was for about 40 d (40 to 80 d). Lamb body weight (BW) was recorded daily for 4 mo. A glucose tolerance test was performed in mo 4 to evaluate glucose concentrations and insulin response. Maternal heat-stressed lamb (HS) presented reduced BW throughout the experimental time (P < 0.05) than maternal thermoneutral lamb (TN; CN = 12.69 ± 0.29 kg and HS = 9.89 ± 0.29 kg). Glucose concentrations were similar between environmental conditions (P > 0.05). Neither the insulin response presented a significance (P > 0.05) between those lambs exposed to HS and TN conditions during gestation. Although maternal exposure to HS can affect performance of the offspring throughout life, metabolic disorders associated with insulin resistance are not a problem at 4 mo. However, preliminary data showed that these same lambs at 8 mo old and 11 mo old show an irregular insulin response in maternal heat-stressed lambs that can persist throughout the life of the offspring.
214 Immuno-detection and stability of SARS-CoV-2 in milk from white-tailed deer
Authors: Raso Hannah , Smith Wraylyn , Tobar Lorena , Reddy Diya , Johnson Jenny , Biesemier Andrew , Harvey Rubin , Raso Dominic S , Finkielstein Carla V
Published: September 2024

SARS-CoV-2, the virus responsible for the COVID-19 pandemic, has expanded to species beyond humans, such as domestic and wild animals, underscoring zoonotic transmission and the urgency of epidemiological preparedness in light of spillovers. In humans, the humoral immune response to SARS-CoV-2 is initially dominated by immunoglobulin (Ig) M and later by IgG and IgA isotypes, with IgA playing a role in mucosal protection. These neutralizing antibodies have been detected in a variety of human fluids, including saliva, respiratory secretions, serum, and breast milk. It is speculated that these antibodies serve to reduce the infectivity of human secretions and viral transmission, while also acting as a form of passive immunity. Thus, we asked whether this immune-protective mechanism is present in a common animal that is both wild and farmed, the white-tailed deer (WTD). We present previously unreported evidence of the existence of neutralizing antibodies against SARS-CoV-2 in serum and milk samples from six WTD harvested during the 2022 and 2023 hunting seasons in central Virginia, USA. Identification of antibodies against SARS-CoV-2 was conducted using species-independent qualitative lateral flow latex immunochromatography from three different commercial sources, as well as enzyme-linked immunosorbent assay (ELISA). Three out of six WTD showed positive antibody signals for both serum and milk using all analytical methods. A fourth sample was positive only for serum, while another sample provided a positive result by ELISA but not lateral flow. The last sample tested negative. Breast milk from pre- and post-SARS-Cov-2-infected human volunteers was used to validate the studies. In addition, RT-qPCR targeting SARS-CoV-2 N, E, and S genes yield negative results in milk samples, further supporting previous studies in human milk that established the absence of viral particles in the fluid. Immunohistochemical analysis of WTD mammary tissue revealed a rare histiocyte positive for SARS-CoV-2, a result that more likely reflects a migration event stimulated by inflammation rather than actual infection. Lastly, in vitro stability studies were carried out in deer and human milk spiked with B.1.1, B.1.1.7, or BA.5 variants. Samples were maintained at room temperature, 37 °C, or 63 °C (pasteurization temperature) and collected at various times. The results showed that while B.1.1 and B.1.1.7 remained largely stable in human samples, they rapidly degraded in deer milk. All virus variants were eliminated from human and deer milk at 63 °C, albeit with different kinetics. These findings underscore the potential role of WTD as reservoirs for SARS-CoV-2 neutralizing antibodies, emphasizing the importance of comprehending zoonotic transmission dynamics and viral variant stability. Such insights may have significant implications for informing public health interventions and surveillance strategies.
465 Comparative analysis of semantic segmentation and deep regression models with supervised pre-training for accurate prediction of pig body weight from video data: Insights from industry-scale datasets
Authors: Bi Ye , Xuan Jianhua , Huang Yijian , Morota Gota
Published: September 2024

Accurate pig body weight (BW) measurement is essential for producers as it is related to pig growth, health, and marketing, yet conventional manual weighing methods are time-consuming and may cause potential stress to the animals. Although there is a growing trend towards the adoption of three-dimensional cameras coupled with computer vision techniques for pig BW estimation, their validation using industry-scale data are still limited. Among the prevailing methodologies, semantic segmentation and supervised pre-training regression are prominent models currently used. Therefore, the objectives of this study were: 1) to estimate pig BW from repeatedly measured video data obtained from a commercial setting, 2) to compare the performance of the two image analysis methods: thresholding segmentation and deep regression approaches, and 3) to evaluate the predictive ability of BW estimation models. An Intel RealSense D435 camera was installed in the commercial farm to collect top-view videos of 540 pigs biweekly at five different time points over three months. At the same time, manually measured BW records were collected using a digital weighing system. We used an automated video conversion pipeline and fine-tuned YOLOv8 to pre-process the raw depth videos. Subsequently, we acquired a total of 151,756 depth images and depth map files. Adaptive thresholding was applied to segment the pig body from the background. Four image-derived biometric features, including dorsal length, abdominal width, height, and volume, were estimated from the segmented images and fitted using ordinary least squares and random forest models. We applied transfer learning by initializing the weights of five deep learning models, including ResNet50, Xception, EfficientNetV2S, ConvNeXtBase, and Vision Transformer, with pre-trained weights from ImageNet. We then fine-tuned these models on the pig depth images. The last layer of each model was adapted to linear regression, enabling direct estimation of BW for each image without the need for additional image pre-processing steps. We employed random repeated subsampling cross-validation, dividing 80% of the pigs for training and 20% for testing, to evaluate prediction performance at each time point. The best prediction coefficients of determination and mean absolute percentage error for each time point were 0.76, 0.86, 0.90, 0.83, 0.90, and 4.57%, 3.76%, 3.01%, 3.41%, 4.84%, respectively. On average, the Xception model resulted in the best prediction coefficient of determination and mean absolute percentage error of 0.90 and 3.01%. Our results suggest that deep learning-based supervised learning models improve the prediction performance of pig BW from industry-scale depth video data.
338 Classroom mental wellness exercise improves wellness domains
Authors: Turner Kari K , Gonzalez John M
Published: September 2024

Poor mental health is a rising problem in undergraduate students, with anxiety and depression leading mental health issues. Insufficient or low physical activity, social isolation, and loneliness are among risk factors that predict mental health issues. Increased demand for already limited mental health resources such as counseling, combined with the stigma surrounding mental health has led to many issues going untreated. Mental health can be comprised of several domains such as academic, physical, emotional, financial, occupational, and stage of life. Improving individual domains will improve overall mental wellness. The objective of this study was to improve mental wellness in individual domains by discussing mental health and encouraging undergraduate students to reduce predictive factors and specifically focus on self-selected wellness domains. Following a 60-min classroom discussion in an animal science course on the prevalence of mental health issues and the common wellness domains (Academic, Emotional, Financial, Interpersonal, Occupational, Physical, and Stage of Life) students (n = 24) rated their current feeling of wellness in each domain on a Likert-scale of 0 (totally lacking) to 6 (completely fulfilled) in an anonymous Qualtrics survey. Strategies on improving the different wellness domains were then discussed, and students were placed into groups based on common domains they would like to improve, and the groups helped individual members identify semester personal goals. A class-wide social media group was formed, and students were given bonus points for posting pictures and texts of progression towards their goals. To encourage participation and support from group members, groups were awarded additional bonus points for having the greatest member activity. After 12 wk, students were given a post-course survey to rate their wellness domain fulfillments, as well as report the amount of time dedicated to improving the specific domains. Pre-and post-course wellness fulfillment ratings were compared using the Mann-Whitney-U Test in SPSS, and Spearman’s rho was used to determine correlations between post-fulfillment ratings and time dedicated to each domain. Fulfillment of Emotional and Physical increased following the exercise (P ≤ 0.016), and Academic tended to increase (P = 0.079). Time spent fulfilling a specific domain was positively correlated with the respective domain for Academic (P = 0.003), Emotional (P < 0.001), Interpersonal (P = 0.006), Physical (P < 0.001), and Stage of Life (P < 0.001) and tended to be positively correlated (P = 0.084) for Occupational. There was no correlation between time spent fulfilling the Financial domain and Financial fulfillment score (P = 0.183). Employing open classroom discussions about mental health and encouraging students to become proactive in their strategies for improving specific mental wellness domains increases their feelings of fulfillment in those domains.
409 From Classroom to Careers: Using coursework to expand student career perspectives and preparedness in animal science
Authors: Abrams Amy
Published: September 2024

Preparing students for careers in the animal science industry often requires a multifaceted approach and involves varying challenges depending on the resources available and student demographics of the academic program. Several factors that contribute to attrition from an animal science program or a lack of preparedness for employment in industry upon graduating include limited knowledge regarding career options, a resistance to learning about different career options, lack of confidence in their abilities, and misconceptions about different careers or skill requirements. The options available to address these issues will vary between academic programs depending on the programs size, financial support, degrees offered, and input from and access to industry partners. Despite diversity between programs, a shared approach to addressing gaps in career preparedness is through the incorporation of industry guided experiential learning practices in the classroom. By strategically integrating curriculum elements that highlight various sectors and specializations, educators can expose animal science students to a wide range of career paths, broaden their perspectives and encourage exploration of different pathways. The saying “you won’t know if it’s right until you try it”, can also apply to career choices. Many students do not have the opportunity to “try” different career options and will not be able to experience their chosen field until they graduate and begin working in industry. Incorporating case studies, guest lectures, related skill development, and industry presentations into coursework provides students with firsthand insights into the day-to-day responsibilities, skills required, challenges, and rewards associated with different career paths. Utilizing experiential learning aimed at career exploration and development not only enriches students’ educational experiences, but it can foster critical thinking and other attributes that are highly valued by industry employers. Furthermore, this coursework can be tailored to address emerging trends, evolving career opportunities, and current industry needs within the field of animal science. By bridging the gap between academic learning and real-world applications, industry centered experiential learning practices equip students with the skills, knowledge, and motivation needed to be successful and meet the needs of industry employers.
284 The influence of growth promoting implants at weaning with different supplementations levels on growth performance and ovarian parameters in developing beef heifers
Authors: Andrews Taylor N , Scholljegerdes Eric J , Perry George A , Cox Shad H , Dunlap Richard L , Cooper Joyce Anne , Bedke Clayton , Gallacher Kristie L , Summers Adam F
Published: September 2024

Administration of a pre-weaning growth promoting implant in beef heifers in Southwestern rangelands can improve growth; however, the effect of administering a second growth promoting implant after weaning on growth and ovarian parameters is unknown. The objective of this study was to determine the effect of supplement level when heifers were administered a second Synovex-C implant at weaning on growth and ovarian parameters. At 2 mo of age heifers (n = 30) were randomly assigned to receive one of three implant treatments: 1) non-implanted (CON), 2) Synovex-C implant at 2 mo of age (BIMP), or 3) Synovex-C implant at 2 and 8 mo of age (WIMP). At 8 mo heifers were randomly assigned to one of two supplement levels (High or Low); thus, creating six treatment groups: High CON (n = 5), Low CON (n = 5), High BIMP (n = 5), Low BIMP (n = 5), High WIMP (n = 5), and Low WIMP (n = 5); assigned in a complete randomized design with a 3 x 2 factorial. Heifers were individually fed supplement three times per week for 25 wk (High 1.26 kg·heifer⁻¹·d⁻¹and Low 0.68 kg·heifer⁻¹·d⁻¹of a 32% CP cube) with refusals weighed back after each feeding. Body weights (BW) were recorded biweekly and grouped in 4 periods (wk 0, 2 to 4, 6 to 14, and 16 to 25). At the end of the supplementation period heifers underwent bilateral ovariectomies. Body weight, height, and length of each ovary was recorded. Surface antral follicles were counted on both ovaries and recorded. Length of the largest follicle was recorded, and follicular fluid (FF) was collected for analysis of estradiol and progesterone concentrations. Ovarian and follicular measurements were analyzed using MIXED procedures in SAS. Average daily gain (ADG) and BW were analyzed as repeated measures using MIXED procedures in SAS. Supplement level × implant interaction tended to influence BW (P = 0.09). Period 4 had increased ADG compared with periods 2 and 3 (P < 0.0001). High heifers had increased ovarian length compared with Low heifers (P = 0.03) and implant tended to increase ovarian length (P = 0.09) compared with CON. Supplement level tended to influence diameter of the largest follicle (P = 0.09). Progesterone FF concentrations tended to be reduced in High heifers compared with Low heifers (P = 0.09). In conclusion, administration of a second Synovex-C implant at weaning did not impact growth performance; however, supplement level tended to hinder follicular parameters.
286 Impact of rate of overwinter gain in March-born yearling range heifers on growth rates and reproductive performance
Authors: Crouch Josie , Mulliniks Travis , Musgrave Jacki A , McCarthy Kacie L
Published: September 2024

Our objective was to determine the impact of rate of overwinter gain in March-born yearling heifers on pre- and post-breeding growth rates and reproductive performance. Red Angus x Simmental crossbred beef heifers [n = 182; weaning body weight (BW) = 242 kg ± 23 kg] were utilized in a 3-yr study conducted at the University of Nebraska, Gudmundsen Sandhills Laboratory (GSL) near Whitman, NE. Using 3-d BW averages collected in January, heifers were stratified by BW and randomly assigned to one of two treatments: 1) to achieve a low overwinter rate of gain at 0.34 kg/d (LO, n = 106), or 2) to achieve a high overwinter rate of gain at 0.68 kg/d (HI, n = 76). To achieve gains, heifers were managed together and had individual access to a dried distillers grain supplement via a C-lock Smart Feeder (Rapid City, SD). Each year, treatments were initiated in January and ended in May (111 ± 4 d). Heifer BW was collected at the start of trial (January), end of the trial (May), pre-breeding (May), pregnancy diagnosis (October), and pre-calving (February). Heifer body condition score (BCS) was collected at pregnancy diagnosis (October) and pre-calving (February; Yr 1 and 2). Before the breeding season, two blood samples were collected 10-d apart via coccygeal venipuncture to determine the percentage of heifers cycling. At breeding, HI-fed heifers had a greater (P < 0.01) BW than LO-fed heifers (813 and 788 kg, respectively; Table 1). However, heifer BW at pregnancy diagnosis and pre-calving were not impacted (P ≥ 0.16) by supplemental treatment. Additionally, there were no differences (P ≥ 0.16) in BCS at pregnancy diagnosis and pre-calving among treatments. Furthermore, rate of gain did not influence (P ≥ 0.38) the percent pubertal prior to the breeding season, pregnancy rates, or the percent that calved in the first 21-d of the calving season. Moreover, rate of gain did not impact (P = 0.89) subsequent calf BW at birth. There was a significant treatment x year interaction (P < 0.01) for subsequent calving date, where HI treatment heifers calved 7-d earlier than LO treatment heifers in Yr 1. This study implies that producers can develop heifers at a less overwinter rate of gain without impacting reproductive performance or subsequent calf birth weight.
PSII-7 Development and assessment of a mobility scoring system for beef cattle
Authors: Guzman Paula Olivares , Schwartzkopf-Genswein Karen S , Bescucci Danisa , Guluarte Jose Ortiz , Ryait Hardeep S , Mohajerani Majid , Sutherland Robert , Van Donkersgoed Joyce
Published: September 2024

Lameness is a disruption of normal gait due to infection, injury, or abnormal conformation, causing pain and discomfort. Several scoring systems have been developed to determine lameness severity; a key indicator in deciding if an animal is fit to withstand transport. However, most scoring systems were developed for dairy cattle and may not be suited for use in feedlot cattle due to the large genetic variation between beef breeds as well as the highly variable environment in which they are housed. Lack of consistency when scoring lameness and reduced ability to detect early lame cattle can result in poor animal welfare and increased costs. The objectives of this study were 1) to develop a mobility scoring system that aids in transport decisions for beef cattle, and 2) to determine observer repeatability using this scoring system. Over a 7-mo period, video cameras were placed in an alley to record the ambulation of individual cattle exiting the processing barn at 4 commercial feedlots in Southern Alberta. Cameras were set to record whole-body videos of cattle walking, running, or trotting. Five researchers trained to use this mobility scoring system, individually evaluated 174 cattle from the collected videos, for fitness for transport and the presence/absence of gait abnormalities: shortness of stride, stiffness (mild, moderate, or severe), limp (mild, moderate, or severe), hip hike, head dropped, head bob, arched back, non-weight bearing, or reluctance to move. The mobility scoring system used was a modified (NCBA and Zinpro) 4-point scale (0-3) for locomotion: 0) an animal with no gait abnormalities; 1) an animal with mild stiffness and shortness of stride; 2) an animal with difficulty taking some steps and one or more of the following: severe stiffness, limp favoring affected limb, limps with a head bob when walking but still bears weight; and 3) an animal reluctant or unable to move, bearing little or no weight on affected limb, the head of the animal is dropped and back arched with pronounced head bob and severe limp detected, or incoordination. Fitness for transport was scored as fit, compromised, or unfit according to the humane transportation guidelines of the Canadian Food Inspection Agency. A kappa statistic was calculated to assess inter-observer reliability for both mobility and transport fitness scoring systems as well as gait abnormalities. The combined mobility scores had substantial agreement between observers (Κ = 0.63; P < 0.001). Mobility score of 2 had the highest agreement among all variables (Κ = 0.88; P < 0.001), followed by head bob (Κ = 0.85; P < 0.001), and arched back (Κ = 0.76; P < 0.001). Results of this study will aid in the development of a mobility score that improves industry stakeholder agreement regarding lameness severity and transport loading decisions.
PSII-8 The effects of diet and finishing phase on the behavioral time budgets of feedlot cattle
Authors: Coon Rachael E , Tucker Cassandra B
Published: September 2024

Feedlot cattle undergo many transitions in diet, social group structure, and environment during the finishing period. Little is known about how their behavior may be altered by these transitions. The objective of our pilot project was to compare the behavior of younger feedlot cattle fed a low-concentrate diet to that of finishing cattle, and to create 24-h time budgets for activity and oral behaviors in these groups. Cattle [n = 20; body weight (BW) = 305 ± 21 kg, mean ± SD] were fed a low-concentrate feedlot diet (60:40, concentrate:forage; ST) and cattle (n = 20; BW = 522 ± 45 kg) received a finishing diet (90:10, concentrate:forage; FI) twice daily. Animals were separated by diet and housed in groups of 10. Trained observers recorded behaviors of each group by live instantaneous recording every 5 min for a continuous 48 h, resulting in 192 h of data collected. We predicted that ST cattle would spend more time eating and ruminating due to the higher forage diet. We also expected that FI animals would rest more and spend less time standing and walking as a result of being more familiar with the environment and their social group structure. We also quantified a wide range of oral behaviors including rumination, grooming and manipulation of non-feed items in the pen. Behaviors were summarized by 24-h period, animal, group, and diet, then averaged by animal, and then averaged again by group (n = 2/diet). Missing values accounted for 3% of the activity data and 11% of the oral behaviors. T-tests revealed that ST cattle ruminated more than FI (352 ± 3 vs. 304 ± 1 min/d, mean ± SE, P = 0.02), but differences between treatments were not detected for time spent eating (196 ± 15 vs. 131 ± 3 min/d), standing (584 ± 13 vs. 588 ± 29 min/d), walking (46 ± 10 vs. 35 ± 5 min/d), or lying (768 ± 16 vs. 772 ± 7 min/d; P ≥ 0.13). When fed the ST diet, cattle spent 5 ± 2 min/d grooming group mates, while FI cattle groomed others for 11 ± 1 min/d, although this was not analyzed statistically because it was rare. Similarly, there were numerical differences in the amount of time spent orally manipulating non-food items (8 ± 3 and 18 ± 1 min/d for ST and FI animals, respectively) that have not been previously described. These results suggest that behavioral differences might be more apparent with larger sample sizes, but with the present experimental design, the predictions were not supported. Nonetheless, these are the first behavioral observations of feedlot cattle and provide a comprehensive time budget of their activity, including a range of oral behaviors over a 48-h period.
PSII-3 Effect of environmental enrichment on pig average daily feed intake and average daily gain in the early nursery phase
Authors: Fortney Daytona , Sundman Emiline R , Gabler Nicholas K , Millman Suzanne T , Johnson Anna K
Published: September 2024

Transition from the sow to nursery is a stressful time for pigs and commonly leads to negative impacts on pig health, welfare, and lifetime performance. The objective of this study was to determine if the addition of a biologically relevant enrichment device affected average daily gain (ADG) and average daily feed intake (ADFI) during the first 2 wk of nursery. A total of 160 mixed-sex pigs (Camborough 1050 X 337, PIC), 19 to 24 d of age [body weight (BW) = 5.77 SD 0.97 kg], were randomly allocated to pens at the Iowa State University Swine Nutrition Farm. Each pen contained 10 pigs (~0.29 m2/pig). Each pen was randomly assigned to one of two treatments: 1) enrichment device with no attractant (positive treatment; n = 8), or 2) no enrichment device (negative treatment; n = 8). Each positive treatment pen had two enrichment devices, consisting of one cotton rope and two biscuits, suspended from the feeder at pig height. The biscuits were replaced daily at about 0800 h throughout wk 1 in nursery (d 0 to d 6). In wk 2 (d 7 to d 13) no pens had an enrichment device. Each pen was equipped with a 4-hole, dry self-feeder measuring 0.61 m long and two affixed nipple drinkers. The feeder was weighed daily, and the pigs weighed weekly. Changes in daily feeder weight and weekly pig BW were used to calculate average daily feed intake (ADFI) and average daily gain (ADG). Pen was the experimental unit. Data were analyzed using the PROC Mixed procedure of SAS. The model included treatment, week, and treatment by week interaction. A P-value of ≤ 0.05 was considered significantly different. There was an observed difference in ADFI and ADG between wk (P ≤ 0.001, Table 1). However, there were no observed differences in ADFI or ADG for treatment (P ≤ 0.79) or treatment by week interaction (P ≤ 0.93). In conclusion, the addition of this biologically relevant enrichment did not improve or impair ADFI and ADG during the first 2 wk of the nursery phase.
PSVII-11 Genetic parameter estimates for lamb survival in prolific and nonprolific ewes
Authors: Lazaro Sirlene F , Oliveira Hinayah R , Schenkel Flávio S
Published: September 2024

Given the increasing global demand for animal products, increasing lamb survival is a key breeding objective for sheep. However, high prolificacy can be associated with increases in fetal and lamb mortality. Therefore, the goal of this study was to estimate the variance components and genetic parameters for lamb survival (LS), using a: 1) single-trait model, where all ewes are analyzed together; and 2) two-trait model, where ewes are grouped in two groups based on birth type [i.e., Group 1 (G1) = single lamb/ewe, and Group 2 (G2) = multiple lambs/ewe]. In both models, LS was defined as the survival of lamb from birth to weaning and analyzed as a threshold trait. A total of 1,040,629 records (215,075 from single and 825,554 from multiple birth) from 319,467 ewes from several breeds/breed groups were available for the study. There were no females with two different types of births. Variance components were estimated through Bayesian inference via Gibbs sampling implemented in the GIBBSF90+ program, fitting a two-trait animal model with maternal effects, in which breed/breed groups were included as fixed effects. Average number of lambs/ewe in G2 was 2.57 (SD = 0.72). Heritability estimated (± SE) for LS on the underlying scale using the single-trait (0.04 ± 0.10) and two-trait model (0.010 ± 0.001 for LSG1 and 0.031 ± 0.004 for LSG2) were low. Maternal heritability estimated by the single-trait model was 0.007 ± 0.043, while by the two-trait model the estimates were 0.010 ± 0.006 and 0.040 ± 0.005 for LSG1 and LSG2, respectively. The genetic correlation estimated between LSG1 and LSG2 was weak and positive (0.25 ± 0.21). The low non-significant genetic correlation between single and multiple birth groups suggests that lamb survival is a different genetic trait in different birth types. Therefore, selecting for improving LS in nonprolific ewes may not necessarily translate to improving LS in prolific ewes. This underscores the need for careful consideration and targeted breeding strategies to achieve desired outcomes in nonprolific and prolific sheep simultaneously. Further studies to define the optimal statistical approach to genetically evaluate LS in prolific and nonprolific ewes are warranted.
PSVII-9 Improvement of feed efficiency in Korean Hanwoo cattle: investigation of feed intake and analysis of residual feed intake (RFI)
Authors: Park Mina , Seong Ha-Seung , Won Jeong-Il , Lee Seung-Soo , Dang Chang-Gwon , Lee Jae-Gu , Cha Jaebeom , Lee Sang-Min , Alam Mahboob
Published: September 2024

Feed efficiency is an important economic trait in beef cattle production, and improving feed efficiency can reduce production costs and environmental impact. Residual feed intake (RFI) is a useful measure of individual feed efficiency, representing the difference between the actual feed intake of an animal and its predicted feed intake based on its body weight (BW) and growth. This study aimed to investigate feed intake and analyze RFI in Hanwoo cattle to improve feed efficiency. Data were collected from 120 Hanwoo steers (9 to 11 mo old) from six different test stations across the country. Individual daily feed intake of concentrates and forage was recorded over 70 d, and BW was measured at the beginning and end of the feeding trial. Daily feed intake was calculated using the TDN values of the concentrates and forage. Expected feed intake was estimated using a linear regression model based on metabolic BW and daily gain. RFI was calculated as the difference between expected and actual feed intake. Average daily gain ranged from 1.05 to 1.71 kg/d, and average daily feed intake ranged from 5.10 to 7.72 kg/d across the test stations. RFI values ranged from -0.84 to 0.95 kg/d, indicating significant variation in feed efficiency among the animals. This study provides valuable information on feed intake and RFI in Hanwoo cattle. Further research with a larger dataset is needed to develop a genetic evaluation model for RFI and to select animals with superior feed efficiency for improving Hanwoo cattle production.