bluuebunny/crossref_metadata_2025_split huggingface dataset:
30 Central Regulation of Kndy Neurons During Undernutrition in Sheep
Authors: Nestor Casey 
Published: November 2023

Abstract
Adequate energy intake is essential for reproduction. While we have known for decades that feed restriction inhibits gonadotropin-releasing hormone/luteinizing hormone (GnRH/LH) secretion, the central mechanisms that govern this reduction during undernutrition remain to be fully elucidated. The past few years, we have focused on examining central mechanisms whereby chronic feed restriction in young sheep results in the inhibition of LH secretion. This presentation will focus on our current understanding of how feed restriction impacts kisspeptin/neurokinin B/dynorphin (KNDy) neurons in young sheep and will give a glimpse into our next few years as we examine how input to KNDy neurons could play a key role in regulating reproduction during undernutrition.
302 Incremental Variables in Predicting Beef Cattle Dry Matter Intake
Authors: Blake Nathan , Walker Matthew , Holaskova Ida , Mata-Padrino Domingo , Wilson Matthew E 
Published: November 2023

Abstract
The great strain of increasing climate variability on animal agriculture necessitates improvement of current production processes, the development of methods to measure individual feed and water intakes, and the improvement of feed and water use efficiency in cattle. The use of machine learning (ML) approaches in predicting beef cattle dry matter intake (DMI) have provided groundwork for improvement of beef cattle production using big data and ML. However, despite wide variation between daily feed intakes, typical variables in animal intake-based ML approaches are not incremental, not allowing for daily prediction of intake. Our work introduces first-differenced intake, climate, and animal performance variables into a ML algorithm to predict beef cattle DMI and increase the immediacy of prediction applications. A total of 745 animals were evaluated in eight test groups from 11/25/2019 to 9/2/2021 in a dry lot equipped with In-Pen Weighing Positions and Feed and Water-Intake Nodes. Relationships among average daily gain (ADG), DMI, residual feed intake (RFI), water intake (WI), residual water intake (RWI), animal performance variables, and environmental variables at the individual animal level were investigated on a first test group of 125 Angus bulls and 53 crossbred steers. Out-Of-Bag root mean square error (OOB RMSE), an internal measure of Random Forest (RF) prediction accuracy, was used as a measure of error between model-predicted and observed DMI. Input variables were first-differenced by differencing a variable’s value between sequential test days for the entire test period. Two models were run using the RF package in R (ntree = 500, mtry = 11), with the first model (M1) using a standard test-train data split and the second model (M2) using all first-differenced and non-incremental observations to train the model. The model incorporating the test-train split performed marginally better than M2 (OOB RMSE = 1.39 and 1.44, respectively), indicating that first-differenced input variables can be used to predict daily individual DMI by within 1.39 kg by using M1. Using percent-increase in MSE (%IncMSE), first-differenced variables were found to be of less overall predictive value than non-incremental variables, with incremental daily gain and first-differenced water intake being ~55 and 45% less predictive than ADG and overall water intake in both M1 and M2. Though first-differenced variables were less predictive than non-incremental variables, inclusion of first-differenced variables allowed for prediction of individual DMI by within 1.39 kg. Our work demonstrates critical preliminary steps in the development of a deployable algorithm for the efficient prediction of DMI and the improvement of beef cattle intake efficiencies for the continued sustainability of animal agriculture.
320 Effects of Sorting Strategy on Within-Pen Variation and Profitability
Authors: Harrison Meredith A , Oltjen James W 
Published: November 2023

Abstract
Decreasing variation in a pen of feedlot cattle reduces overfeeding, increases carcass quality and uniformity, and improves economic returns. The objective of this study was to evaluate the effect of sorting by body weight (BW) or expected days on feed (DOF) on pen performance and profitability. Ninety-six Angus-cross steers (initial BW = 360 ± 28 kg) were randomly assigned to sorting by BW or DOF determined using the Davis Growth Model and initial body measurements for BW, hip height, back fat thickness (BF), and ribeye area. Steers within BW and DOF sort groups were randomly assigned to one of two replicates. Within replicate, BW groups were divided into light and heavy pens (initial BW = 323 and 366 kg, respectively), and DOF groups were divided into short and long pens (DOF = 119 and 160 d, respectively), for a total of 8 pens with 12 steers in each pen. Pen feeding was managed using the slick bunk method and time of marketing was determined based on observation of an average pen BF of 1.1 cm. Steers were harvested at a commercial abattoir and individual carcass characteristics were recorded. Profit was calculated as carcass value minus feed costs. For comparison of sorting treatments, pen was the experimental unit, and treatment means and variances were compared using a t-test and F-test, respectively. Steers were harvested in three groups: both heavy-BW sort pens and both short-DOF sort pens were harvested after 84 d, both long-DOF sort pens and one light-BW sort pen were harvested after 104 d, and the final light-BW sort pen was harvested after 116 d on the finishing ration. There were no differences in mean initial BW (P = 0.95) or initial percent empty body fat (EBF; P = 0.28), but variation in initial BW was reduced (P &lt; 0.01) for the BW sort group. Final mean BW did not differ between sort groups (P = 0.54), but variance in final BW and hot carcass weight was less (P &lt; 0.01) for the group sorted by BW. Final percent EBF also did not differ between groups (P = 0.41), but percent EBF variance was 2.4 %-units for DOF and 2.9 %-units for BW sorted pens, although differences were not statistically significant. There were no differences in average daily gain or feed conversion rate between sort groups. Variation in yield grade, BF, and marbling score were numerically reduced for the DOF group; however, differences were not statistically significant (P &gt; 0.10). Average profit per steer was $ 321.42 and $ 235.05 for DOF and BW sorted groups, respectively. Sorting by DOF increased profitability by 26% by increasing harvest BW, improving uniformity, and decreasing overweight carcasses.
321 Rancher Motivations for Joining Sustainability Programs
Authors: Klopatek Sarah C , Oltjen James W , Roche Leslie , Stackhouse-Lawson Kim R , Cantwell Allison 
Published: November 2023

Abstract
Livestock’s environmental footprint has become a pivotal concern for both consumers and investment corporations. To stay competitive in the sustainable foods movement, the beef industry has sought to improve sustainability within their own supply chains. However, before system sustainability can be achieved, more sustainability practices must be adopted and implemented by the foundation of the system. Therefore, to gain insight into motivations of ranchers for adopting new sustainable practices we administered an online multi-state survey to cattle ranchers in collaboration with state Cattlemen’s Associations. In total, the survey consisted of 45 questions and was divided into four sections including: 1) rancher demographics, 2) ranching educational resources, 3) current best management practices, and 4) willingness to join new rancher sustainability program. Of the survey participants (n = 884), when asked what made them trust/ believe in a ranching educational program, 64% of ranchers stated they trusted (very or extremely) science, 55% or ranchers stated they trusted a ranching educational program if the program was partnered with state cattlemen’s associations, and 32% of ranchers stated they trusted the program if other ranchers they knew were currently enrolled in the program. When survey participants were asked who they trusted most to dispense ranching educational information 79% trusted veterinarians (very or extremely), 63% trusted extension agents/ farm advisors, 57% trusted professors (very or extremely), and 54% trusted other cattle producers. In regards to where cattlemen acquired ranching information 94% utilized trade publications or magazines, 90% utilized university or extension, 70% utilized state or national cattlemen’s meetings, and 52% utilized social media. The top three reasons why survey participants would choose to adopt a new ranching practice included increases profitability 79%, improves animal health 78%, and expected benefits greatly outright the cost or effort to implement 51%. Meanwhile, only 18% of ranchers selected improving environmental health as one of their top 3 reasons for adopting a new ranching practice. In terms of best management practices, 77% of producers stated they had a grazing management practice, however only 29% had their plane written down. Finally, the survey indicated that ranchers who were male, had been through the Beef Quality Assurance training, and were enrolled in a land assistance program were more likely to state that joining a sustainability program would be beneficial to their operation (P &lt; 0.05). Overall, this survey provides the necessary insight into why and how ranchers learn about new ranching practices and provides a possible framework for how to develop successful ranching educational and sustainability programs in the future.
351 Effects of Replacing Soybean Hulls with Molasses During the Receiving Period of Feedlot Steers
Authors: Raudales Quijada Angel A , Henry Darren D H , Pagoada Romero Alejandro A J , Fontes Pedro L P , Burato Samir , Messias Ciriaco Francine M 
Published: November 2023

Abstract
An experiment was conducted to evaluate the effects of replacing soybean hulls with molasses in the receiving diets of weaned feedlot steer-calves on growth performance, nutrient digestibility, enteric methane emissions, and blood inflammatory marker. Eighteen growing Angus crossbred steers (293 ± 11 kg body weight) were used in a completely randomized design with two diets, which were considered treatments. Diets consisted of (DM basis): 1) 46% corn silage, 25% dried distillers grains with solubles, 27% molasses, 0.5% limestone, and 1.5% vitamins and mineral packet (MOL), and 2) 46% corn silage, 22% dried distillers grains with solubles, 30% soybean hulls, 0.5% limestone and 1.5% vitamins and mineral packet (SBH). The experiment consisted of a 42-d period. On d -2 and -1, steers were weighed, and the average was considered initial body weight. On day -1, after weighing, steers were transported via truck and trailer for 12 h (6 h in one direction then 6 h back to the facility) to induce stress experienced by calves when shipped to another location as is standard in the beef industry. Steers were provided hay the evening they returned to the facilities. Steers were stratified by initial body weight and randomly assigned to individual pens, which were randomly assigned to one of the two treatments (MOL or SBH; n = 9 steers/treatment). Dietary treatments started on d 0. Other body weight measurements were recorded on d 7, 14, 21, 28, 35, 41 and 42. Final body weight was considered the average of two consecutive weights recorded on d 41 and 42. Blood samples were collected via venipuncture on days corresponding to body weight measurements. Feed intake data was collected daily by measuring dry matter of feed offered and orts refused. From d 14 to 20, breath samples were collected, using the sulfur hexaflouride technique, to determine enteric methane production, and feces were collected to determine apparent total tract nutrient digestibility. Data were analyzed using the MIXED procedure of SAS and steer as the experimental unit. The model included the fixed effect of treatment. Initial (P = 0.82) and final body weight (P = 0.64) were not affected by treatment. Additionally, no effects of treatment were observed on dry matter intake (P = 0.80) or average daily gain (P = 0.48). Data on enteric methane emissions, nutrient digestibility, and plasma LPS binding protein are still being analyzed. Preliminary data indicate that molasses can replace soybean hulls as an energy source in feedlot receiving diets without affecting animal performance.
342 Effectiveness of Liver Abscess-Controlling Antibiotic on Rumen Kinetics of Beef Steers Consuming a High-Grain Diet
Authors: Batista Luiz Fernando Dias , Rivera Madeline E , Mendes Egleu D M , O'Reilly Keara , Tedeschi Luis O 
Published: November 2023

Abstract
Virginiamycin (VM) possesses antimicrobial properties due to its blocking of protein synthase in Gram-positive bacteria, allowing it to reduce lactic acidosis and the incidence of liver abscesses in ruminants. Ruminal acidosis is a common metabolic disorder that affects feedlot and dairy cattle and occurs when the supply of organic acids from fermentation exceeds its absorption and degradation, accumulating acid content in the rumen. The objective of this study was to evaluate the effects of three different doses of VM administration on in vivo and in vitro ruminal digestion kinetics of beef steers consuming a high-grain diet [metabolizable energy (ME): 2.99 Mcal/kg; Crude Protein (CP): 15.2 % dry matter basis (DM)]. Nine ruminally cannulated British-crossbred steers (596 ± 49 kg) were assigned to this experiment. Animals were housed in three pens (n = 3/pen) equipped with a Calan gate feed system and water trough. Pens were enrolled in a 3×3 Latin square design containing three periods of 16 d, and a 5-d washout interval between periods. Dietary treatments consisted of VM administration at 0 mg/d (VM0), 180 mg/d (VM180), and 240 mg/d (VM240). During d 15 and 16 of each period, about 600 mL of rumen fluid was collected before (0 h) and at 4, 8, 12, and 16 h relative to the morning feed (0730 h) pH and redox potential (Eh) measurements were taken immediately after collection using a portable pH and redox meter, and subsamples were taken for volatile fatty acids (VFA), and NH3-N analyses. During the 4-h post-morning feed rumen collection, rumen inoculum was utilized to perform in vitro gas production (IVGP) measurements. All statistical procedures were performed using SAS software where steer was considered the experimental unit, and period and square were included as random. Acetate, propionate, and total VFA did not differ among treatments (P ≥ 0.50), whereas butyrate increased linearly (P = 0.033) as the VM dose increased. Acetate:propionate ratio did not differ among treatments (P = 0.273). Lactate concentration decreased linearly (P = 0.027) as the VM dose increased; likewise, pH increased linearly (P = 0.019) as the VM dose increased. Branched-chain VFA and NH3-N concentrations increased linearly (P ≤ 0.056) as the VM dose increased. The total and rate of gas production were similar among treatments (P ≥ 0.161). However, second-pool gas production increased linearly as VM inclusion increased (P = 0.023). The in vitro neutral detergent fiber digestibility did not differ among treatments (P = 0.984). The provision of VM altered the rumen dynamics in a dose-dependent manner. Animals consuming high-grain diets will likely promote rumen health through a more stable pH and fermentation profile.
403 Awardee Talk: Characterization of Rumen Microbiome and Immune Genes Expression of Crossbred Beef Steers with Divergent Residual Feed Intake Phenotypes
Authors: Taiwo Godstime A , Ogunade Ibukun M 
Published: November 2023

Abstract
We investigated whole blood and hepatic mRNA expressions of immune genes and rumen microbiome of crossbred beef steers with divergent residual feed intake (RFI) phenotype to identify relevant biological processes underpinning feed efficiency in beef cattle. Low-RFI beef steers (n = 20; RFI = - 1.83 kg/d) and high-RFI beef steers (n = 20; RFI = + 2.12 kg/d) were selected from a group of 108 growing crossbred beef steers (average BW = 282 ± 30.4 kg) fed a high-forage total mixed ration after a 70-d performance testing period. At the end of the 70-d testing period, liver biopsies and blood samples were collected for total RNA extraction and cDNA synthesis. Rumen fluid samples were also collected for analysis of the rumen microbial community. The mRNA expression of 84 genes related to innate and adaptive immunity was analyzed using pathway-focused PCR-based arrays. Differentially expressed genes were determined using P-value ≤ 0.05 and fold change (FC) ≥ 1.5 (in whole blood) or ≥ 2.0 (in liver). Gene ontology analysis of the differentially expressed genes revealed that pathways related to pattern recognition receptor activity, positive regulation of phagocytosis, positive regulation of vitamin metabolic process, vascular endothelial growth factor production, positive regulation of epithelial tube formation and T-helper cell differentiation were significantly enriched (FDR &lt; 0.05) in low-RFI steers. In the rumen, the relative abundance of PeH15, Arthrobacter, Moryella, Weissella and Muribaculaceae was enriched in low-RFI steers, while Methanobrevibacter, Bacteroidales_BS11_gut_group, Bacteroides and Clostridium_sensu_stricto_1 were reduced. Our study found that low-RFI beef steers exhibit increased mRNA expression of genes related to immune cell functions in whole blood and liver tissues, specifically those involved in pathogen recognition and phagocytosis regulation. Additionally, these low-RFI steers showed differences in relative abundance of some microbial taxa which may partially account for their improved feed efficiency compared with high-RFI steers.
428 Awardee Talk: Can the Ruminal Microbiome Ever Answer All the Questions That Nutritionists have?
Authors: Callaway Todd 
Published: November 2023

Abstract
The rumen microbial consortium has long been viewed as a “black box”, where we recognize what goes in, and most of what comes out, but the ruminal catabolic and anabolic activity remains shrouded in uncertainty. Microbiologists from the 1940s through the early 2000s identified microbes responsible for ruminal feedstuff degradation, highlighted animal-important fermentation endproducts (such as volatile fatty acids, VFA), and examined how microbes interacted with each other (e.g., interspecies hydrogen transfer), and with the host animal. However, our knowledge was dependent on our ability to grow anaerobic microbes in pure or mixed cultures, but it became apparent that our limiting factor was that we could culture &lt;10% of the ruminal microbes. In the past 15 years, there has been a proliferation of new techniques to identify what is occurring in the rumen of live ruminants such as, culturable and unculturable microorganism populations, microbial biochemical pathways and important metabolic intermediates, potential interactions between microbes, and biologically relevant endproducts that impact host animal physiology, health, and production efficiency. As Next Generation Sequencing (NGS) has become increasingly affordable, there has been a surge in research examining the “microbiome” with a resultant influx of massive datasets. However, without the ability to connect microbial populations to biochemical degradative pathways, endproducts, microbial interactions or animal production parameters, this information is of limited impact in ruminant nutrition. Ruminant nutrition is on a precipice where we can finally fully integrate microbiology with metabolomics and animal performance and nutrition. Advancements in ruminal microbiology will allow us to fully grasp the functional nature of the microbial ecosystem and where it fits within ruminant nutrition, which will improve animal productivity and ruminant-derived protein food production sustainability.
327 A Novel, in Vivo Model to Increase Endogenous Pancreatic and Small Intestinal Carbohydrase Activity to Evaluate Limitations of Small Intestinal Starch Digestion in Cattle
Authors: Trotta Ronald J , Swanson Kendall C , Klotz James L , Harmon David L 
Published: November 2023

Abstract
Consumption of high-grain diets by cattle can result in large quantities of starch that flow to the small intestine for potential enzymatic digestion. However, small intestinal starch digestion is potentially limited because of insufficient activity of pancreatic and/or small intestinal carbohydrases. Studies suggest regulation of carbohydrase activity is complex in cattle and perhaps uncoordinated in response to luminal carbohydrate flow. The objective of this experiment was to use postruminal casein infusion and exogenous glucagon-like peptide 2 (GLP-2) administration, known stimulators of pancreatic and small intestinal function, to evaluate their effects on pancreatic and small intestinal carbohydrase activities. Twenty-four Holstein steers [250 ± 23 kg body weight (BW)] were used in a randomized complete block design with a 2 × 2 factorial arrangement of treatments. Steers were fed an alfalfa cube-based diet to limit dietary starch intake. Steers received a continuous abomasal infusion of 4 g/kg of BW of raw corn starch combined with either 0 or 1.33 g/kg of BW of casein for 7 d. Steers received subcutaneous injections in two portions daily of excipient (0.5% bovine serum albumin) or 100 µg/kg of BW GLP-2. This resulted in four treatments: control, casein, GLP-2, and casein + GLP-2. At the end of the 7-d treatment period, steers were slaughtered for pancreatic and small intestinal tissue collection. Data were analyzed using the GLM procedure of SAS. Postruminal casein infusion increased (P ≤ 0.03) pancreatic mass by 12.6%, total pancreatic α-amylase activity by 50%, and postruminal starch disappearance from 96.7% to 99.3%. Exogenous GLP-2 increased (P &lt; 0.01) total small intestinal mass and small intestinal mucosal mass by 1.2 kg and 896 g, respectively. Relative to control, GLP-2 and casein + GLP-2 treatments increased (P = 0.04) total small intestinal α-glucosidase activity (sum of maltase, isomaltase, glucoamylase) by 83.5%. Total small intestinal maltase, isomaltase, and glucoamylase activity was 90%, 100%, and 66.7% greater for GLP-2 and casein + GLP-2 steers compared with control. The use of postruminal casein infusion and exogenous GLP-2 administration resulted in four distinct carbohydrase activity phenotypes. Relative to control, casein increased pancreatic α-amylase activity, GLP-2 increased small intestinal α-glucosidase activity, and the combination of casein and GLP-2 increased both pancreatic α-amylase activity and small intestinal α-glucosidase activity. This approach provides a novel in vivo animal model to selectively increase endogenous carbohydrase activity to overcome complications of coordinating carbohydrase activity with luminal nutrient flows. This model could be useful to understand physiological mechanisms that might improve small intestinal starch assimilation and efficiency of cattle consuming high-grain diets.