Journal of animal science最新文献

{"title":"PSII-23 Evaluation of diets varying in rumen available protein on methane production in continuous culture fermenters.","authors":"Yairanex Roman Garcia, Aimee N Hafla, Pablo J Guiroy, Maria I Sardi, Samia El-Haddad, William H Kolath, Guillermo F Schroeder, Pedro Veiga","doi":"10.1093/jas/skaf300.656","DOIUrl":"https://doi.org/10.1093/jas/skaf300.656","url":null,"abstract":"The objective of this study was to evaluate methane emissions and fermentation parameters in in vitro continuous culture (IVCC) fermenters receiving feedlot diets with varying levels of rumen available protein (RAP, sum of degradable intake CP and recycled nitrogen). Diets were formulated with the Cargill MAXTM system, which utilizes a model to estimate microbial CP (MCP) based on type and amount of dietary carbohydrates fermented in the rumen. Twelve fermenters were used in a randomized block design experiment with two 10-d periods. Dietary treatments were: DEF (RAP deficient by 20% compared to MCP requirements), BAL (balanced to MCP), EXNPN, (20% excess RAP compared to MCP), EXTP (20% excess RAP compared to MCP) but replacing NPP by true protein (urea vs soybean meal). Fermenters (~ 2 L capacity) were fed (~ 80) a steam flaked corn, DDGS and wheat hay-based TMR diet once daily. Effluent was collected the last 2 days of the experiment to determine nutrient degradation, VFA, and microbiome composition. Methane in the headspace was monitored continuously in all fermenters using a Micro-Oxymax Respirometer (Columbus Instrument Inc., Columbus OH). Data was analyzed with the lmer package in R with a model that contained the fixed effects of diet, their interaction with time (if applicable), and the random effects of period and fermenter. The DEF diet increased methane production (µmol/h) by approximately 43% compared to all other treatments (P < 0.01), and the effect was consistent across all hours, with no difference between the other diets. There was a tendency (P = 0.07) for excess diets to increase NDF degradation compared to DEF and BAL (34.0, 35.0, 43.1, 43.6% for DEF, BAL, EXNPN, and EXTP respectively, SEM=4.8%). There was no effect of diet on VFA production or proportion except for isovalerate which decreased (P = 0.03) only in EXNPN. Ammonia concentration was higher (P < 0.05) in EXNPN at 1-4 h post feeding. There was a tendency (P = 0.09) for the diet to affect bacterial DM flow with BAL having the highest flow (6.46, 7.24, 6.88, 5.82 g/d for DEF, BAL, EXNPN, and EXTP respectively, SEM = 0.72). There were no effects of diets on methanogens. Microbiome diversity was different (P = 0.03) for the DEF compared to the other diets. The BAL and excess diets had a more diverse carbohydrate-active potential than the DEF diet, suggesting that the DEF diet supports complex fermenting bacteria, while the BAL and Excess diets encourage a more diverse set of fermenting bacteria. These findings suggest that diets varying in RAP modulate the metabolic potential of the microbiome, which in turn affects methane production. This study shows that changes in RAP levels can have an impact on methane production in feedlot diets.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"7 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"75 Re-evaluating recommendations for Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) for adult dogs: A dose-response study on antioxidant status.","authors":"Fumiko Imai, Lindsey Rummell, Jordyn Welsh, Sydney Banton, Pawanpreet Singh, Janelle Kelly, Jennifer L Saunders-Blades, David W L Ma, James R Templeman, Lindsay E Robinson, Anna K Shoveller","doi":"10.1093/jas/skaf300.142","DOIUrl":"https://doi.org/10.1093/jas/skaf300.142","url":null,"abstract":"Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two common and beneficial n-3 fatty acids for dogs. The minimum required dose for adult dogs at maintenance has not been established, but the National Research Council (NRC) provides a combined recommended allowance (RA) for EPA+DHA of 0.03 g/kg body weight (BW)⁰·⁷⁵ and safe upper limit (SUL) of 0.37 g/BW⁰·⁷⁵. The SUL is based on findings in geriatric Beagles (9.5–11.5 years old), where supplementation at 0.45 g/BW⁰·⁷⁵ EPA+DHA resulted in lower α-tocopherol concentrations and higher lipid peroxidation. However, similar studies have not been conducted in healthy adult dogs, nor has a broader evaluation of oxidative balance been performed. To address this gap, an 8-week dose-response study was conducted to evaluate how feeding graded inclusions of dietary EPA+DHA may impact lipid metabolism of healthy, adult dogs. We hypothesized the RA minimizes lipid peroxidation and antioxidant depletion but may not fully maximize potential anti-inflammatory benefits, while higher doses may enhance immune benefits but may also increase oxidative stress and antioxidant depletion. Twenty-seven client-owned dogs (25 Siberian Huskies and 2 Alaskan Huskies) participated, consisting of 13 females (4 intact, 9 spayed) and 14 males (3 intact, 11 neutered), aged 1-12 years with a mean age of 6.9 ± 5.8 years and a mean BW of 21.5 ± 6.8 kg (mean ± SD). Following a 4-week acclimation with once-daily feeding at 15:00 with a commercial extruded diet, dogs were blocked by age and BW before random assignment to one of three dietary groups. All dogs were fed the same low-fat experimental diet (39.8% crude protein, 13.8% crude fat, 3.0% crude fibre). The diet was supplemented with fish oil (containing 0.53g EPA and 0.38g DHA per mL) to achieve daily EPA+DHA intakes of 0.03 g/BW⁰·⁷⁵ (LOW), 0.45 g/BW⁰·⁷⁵ (MOD), and 0.71 g/BW⁰·⁷⁵ (HIGH). Feed intake was adjusted to maintain BW throughout the study period. Fasted blood samples were collected at weeks 0, 4, and 8 to assess serum fatty acid profile, lipid fractions, inflammatory cytokines, α-tocopherol, and malondialdehyde (MDA). Data were analyzed using PROC GLIMMIX in SAS, where dog was treated as a random effect, week as a repeated measure, and dose of EPA+DHA as a fixed effect. Statistical significance was declared at P≤0.05. Serum α-tocopherol concentrations were comparable across all groups at week 0 and increased similarly among groups at week 4 (p< 0.01). Dogs fed HIGH had lower α-tocopherol concentrations than LOW group (p< 0.05) but did not differ from MOD group (p=0.42) at week 8, indicating EPA+DHA intake is related to antioxidant depletion. These findings offer valuable insights into the impact of EPA and DHA supplementation on oxidative balance and may help refine current NRC recommendations and inform best practices for dietary inclusion.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"4 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"384 Variability in bovine liver abscess frequency, proportional mass, and location within abscess severity scores.","authors":"Macy T Lawrence, Jay W Johnson, Trent Schwartz, Loni W Lucherk, Ty E Lawrence","doi":"10.1093/jas/skaf300.054","DOIUrl":"https://doi.org/10.1093/jas/skaf300.054","url":null,"abstract":"Liver abscesses (LA) are a multifactorial, polymicrobial disease that occur in all ages and classes of cattle. Abscesses vary in count, size, and shape. Bovine LA are associated with reduced feed intake, reduced weight gain, decreased feed efficiency, and decreased carcass yield. Liver abscess scoring systems are based upon visual appraisal of the external surfaces of the parenchyma. Limited research has been conducted on the location effect of LA within the bovine liver or the totality (frequency or mass percentage) of LA contained within the liver. The objective of this study was to document location effects of LA within finished bovine, and to compare visual evaluation of LA external on the liver to total number of LA. Abscessed livers (n = 294) were assigned an Elanco Liver Score by visual appraisal on-line in commercial harvest facilities; livers were removed offline for intensive evaluation. Diaphragmatic and visceral surfaces of each liver were photographed, and visual external LA number were recorded for both surfaces. Liver abscesses were individually excised, and the total count and mass percentages were determined for each liver. Relative location of visually external LA was determined by creating a frequency heatmap. Data were analyzed using GLIMMIX models; the fixed effect was visually appraised Elanco liver score, and means were separated using the LINES option. Mass percentage and frequency of abscesses were estimated from visual surface counts using REG procedures. Percentage of liver mass represented by LA was greatest (P < 0.01) in livers scored A+Open (13.4%), compared to A+Adhesion or A+ (10.5 and 8.3%, respectively), which were greater (P < 0.01) than livers score A or A- (3.1 and 1.6%, respectively). Similarly, frequency of LA was greater (P < 0.01) for livers scored A+Open (31.0) than all other scores (A+ = 14.1, A+Adhesion = 11.2, A = 3.5, A- = 2.5). Heatmap analysis indicated that LA were observed (P < 0.01) on the diaphragmatic (3.9) surface of the liver at twice the frequency of the visceral surface (1.9). Abscesses within the liver parenchyma and not visible on either surface were excised in the greatest (P < 0.01) frequency for livers scored A+Open (18.8) in comparison to those scored A+ (7.8), A+Adhesion (6.0), A (0.9), or A- (0.7). Regression outcomes indicate strong ability (R2 = 0.83 to 0.90) to estimate total frequency of LA via counting diaphragmatic and/or visceral surfaces. In contrast, linear regression suggests a weak ability (R2 = 0.25 to 0.27) to estimate the mass percentage of LA from diaphragmatic or visceral surface counts, due to extreme variability in absolute LA size (< 1 g to >11,500 g). These data support the creation of a new LA scoring system to include the wide variability in A+ severity.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"6 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PSVII-26 Integrating hands-on animal behavior experience into an undergraduate animal science course.","authors":"Morgan Marquardt, Ruth Woiwode","doi":"10.1093/jas/skaf300.755","DOIUrl":"https://doi.org/10.1093/jas/skaf300.755","url":null,"abstract":"Compared with years past, undergraduate animal science students have little prior experience with farm animals. Limited experience with animals leaves students with an inadequate understanding of how to decipher animal behavior. In order to be well-prepared for managing animals and people in future careers, it’s important for animal science students to have a foundational understanding of animal behavior. To expose students to established methods for animal behavior research and increase their overall understanding of animal behavior, weekly hands-on activities were assigned as a part of an undergraduate animal behavior and welfare course. Cattle handling at a commercial feedlot had been previously recorded and this video footage was edited to produce clips approximately five minutes in length. For each of 14 weeks during the semester, students used an ethogram to observe and record cattle behavior in the video clips. The objectives were 1) to introduce animal science students to methods for studying animal behavior, and 2) increase their understanding of cattle behavior. This approach was designed to reinforce concepts presented in lecture. Weekly activities were used to measure students’ understanding of cattle behavior, and their use of established tools to study animal behavior, using the mastery learning approach. Participation in weekly animal behavior activities contributed to student success in the course.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"5 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"30 Investigation into the relationship of mitochondrial haplotype on respiratory complex I activity in beef cattle skeletal muscle.","authors":"Mackenzie C Batt, Lauren E Seier, Abigail Webb, Andrew Lakamp, Anna M Fuller, Dustin T Yates, Kristi Montooth, Jessica L Petersen","doi":"10.1093/jas/skaf300.021","DOIUrl":"https://doi.org/10.1093/jas/skaf300.021","url":null,"abstract":"Mitochondria regulate energy metabolism by converting nutrients into ATP through the process of oxidative phosphorylation. A series of protein complexes in the inner mitochondrial membrane facilitate ATP production via electron transfer, with respiratory complex I (i.e., NADH dehydrogenase) transferring electrons from NADH to build the proton gradient that facilitates ATP synthesis. Efficient complex I activity supports ATP production in muscle tissue, sustaining mitochondrial function and metabolic processes essential for muscle efficiency and overall animal performance. Despite mitochondria’s key role in energy production, mitochondrial DNA (mtDNA) variation has been largely overlooked in livestock breeding, with its impact on economically relevant traits remaining largely unexplored due to the focus on paternal genetics and nuclear DNA. Therefore, the objective of this study was to investigate the relationship between mitochondrial haplotype and complex I activity in skeletal muscle to determine if genetic variation in mtDNA influences complex I function. Haplotype was determined by performing low-pass sequencing (average 55X mitochondrial coverage) on DNA of 84 beef steers from the composite University of Nebraska-Lincoln herd. Sequencing data were trimmed and aligned to the ARS-UCD2.0 genome using BWA-MEM and variants called using GATK. Mitochondrial haplotypes were defined by considering only nonsynonymous variants. Nine haplotypes were considered with 4-25 (average = 9) cattle represented per group. Calorimetric assays were used to quantify citrate synthase and complex I activities of sternomandibularis muscle homogenates collected at harvest. Complex I activity was normalized to citrate synthase activity to account for differences in mitochondrial content. Citrate synthase activity averaged 176.40 ± 83.60 nmol/min/mg of protein. Complex I activity normalized to citrate synthase activity averaged 0.99 ± 0.67. A linear mixed model was implemented with complex I activity normalized to citrate synthase as the dependent variable to assess the effect of mitochondrial haplotype on complex I activity. Fixed effects included mitochondrial haplotype, contemporary group (birth and harvest cohort), and age at sampling. A random animal effect, modeled using a genomic relationship matrix based on ~90,000 nuclear genomic markers, accounted for polygenic influences. Mitochondrial haplotype was not associated with complex I activity for these steers. Age and contemporary group also had no effect on complex I activity, suggesting that variation in these animals was driven by factors other than mitochondrial haplotype. Given that mitochondrial respiratory complexes are derived from both mitochondrial and nuclear-encoded genes, nuclear genetic variation or the interaction of nuclear and mitochondrial genes may have been more influential than complex I haplotype alone in determining the complex’s efficiency. Future analysis of data from more animals and consi","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"22 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PSXIII-19 Effect of a soluble trace-mineral based supplement on water intake, growth performance, and mineral status of newly weaned beef calves.","authors":"Sebastian Maresca, Agustín Vera, Sebastian O Lopez Valiente, Alejandro M Rodriguez, Nicolas DiLorenzo","doi":"10.1093/jas/skaf300.713","DOIUrl":"https://doi.org/10.1093/jas/skaf300.713","url":null,"abstract":"Early oral hydration and the provision of key nutrients may reduce the negative impact of stress related to post-weaning management, marketing, and transportation in newly received calves. This study evaluated a strategy to supply water and trace-minerals to newly weaned feedlot calves during the first 55 days following their arrival. Angus heifer calves (n = 18; initial body weight = 148 ± 11 kg) were individually weighed after 12 hours of fasting, housed in 6 pens (3 animals/pen), and randomly assigned to treatments (3 pens/treatment): Control (CON): no mineral supplementation, or Soluble Trace-Mineral Based Supplement (SUP): trace-mineral based drinking solution providing 3.0 g/head/d of mineral complex (Hidromix, Nutralmix, Argentina). The mineral solution was dosed in drinking water using a water-powered dosing pump (D9AL2, Dosatron, France). Heifers had ad libitum access to alfalfa hay (60.1% TDN, 14.2% CP on a dry matter basis). Water intake was measured daily throughout the experiment. Body weights (BW) were measured on days 0 and 55, and blood samples were collected on days 25 and 55 to determine Cu, Se, and Zn serum concentrations. Pens were considered the experimental unit, and data were analyzed using the PROC MIXED procedure of SAS, considering treatment and day as fixed effects and pen as a random effect. Water intake was greater for SUP than CON heifers (SUP = 17.6, CON = 15.6 L/d; P = 0.001) with no treatment × day interaction (P = 0.98). Treatments did not affect final BW (SUP = 173, CON = 170 kg; P = 0.90) or average daily gain (SUP = 0.420, CON = 0.444 kg; P = 0.91). There was no treatment effect or treatment × day interaction for Cu serum concentration (SUP = 72.3, CON = 73.1 µg/dL; P > 0.10). Serum Se concentration was greater in SUP than CON (SUP = 78.8, CON = 5.1 µ/l; P < 0.001) and a treatment × day interaction was observed (P = 0.05). The concentration of Zn tended to be greater in SUP than CON (SUP = 0.83, CON = 0.65 µ/ml; P = 0.07) with no treatment × day interaction (P = 0.98). The preliminary results suggest that providing a soluble trace-mineral supplement in drinking water enhances water intake and mineral status but does not result in increased growth performance in newly weaned beef calves.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"78 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1 Lecture I: Modeling the dynamics of complex systems: Incorporating AI and HPC into dynamic modeling.","authors":"Ignacio J Martinez Moyano","doi":"10.1093/jas/skaf300.086","DOIUrl":"https://doi.org/10.1093/jas/skaf300.086","url":null,"abstract":"Why do things change over time? Why is it difficult to identify the potential consequences of the implementation of policies in dynamic systems? Why do so many actions designed to correct problems do not work or make things worse? Change and complex interaction are the norm in real-world systems. Actors in such complex systems face challenges and problems when they try to accomplish activities geared toward meeting their goals. Decision-making processes are at the core of how organizations, and individuals, deal with the causes and consequences of complexity and change in complex systems. Because of the inherent unpredictability of complex systems, and because of multiple non-linear effects and time delays in how complex systems respond, decisions made to address or to prevent problems are often the reason why problems persist over time or emerge in the future. Linear and traditional analytic approaches (such as statistics or econometrics) often fall short in helping understand, and change, problematic behavior in complex systems. The system dynamics approach, based on feedback and control theory, is well suited for tackling such complex and dynamic phenomena. In this presentation, the basic principles underlying dynamic feedback systems and the use and applications of system dynamics modeling will be reviewed. Also, general insights related to the use of AI and HPC in dynamic modeling of complex systems will be discussed.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"17 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"377 Effects of corn silage inclusion rate in the finishing diet on performance, carcass characteristics, and liver abscess incidence of Holstein and Beef × Holstein steers.","authors":"Melanie Pimentel Concepción, Daniel Buskirk, Andrea Garmyn, Jongkyoo Kim, Jerad Jaborek","doi":"10.1093/jas/skaf300.098","DOIUrl":"https://doi.org/10.1093/jas/skaf300.098","url":null,"abstract":"The objectives were to investigate feedlot performance, carcass traits, and liver abscess incidence of Holstein (HO) and Beef × HO (B×HO) steers fed different corn silage inclusion rates in the finishing diet. After a 21-d adaptation, treatments were assigned in a 2x2 factorial arrangement, factors being breed type (HO or B×HO) and dietary inclusion of 20% or 40% corn silage (20CS or 40CS). Steers (n=120) were allocated to five pens per breed type by diet combination. Initial BW (266±18.7 kg) was included as a covariate for statistical analyses. Harvest occurred when treatments reached an average empty body fat (EBF) of 30% predicted by ultrasound. Carcass data were collected following a 48-h chill. The B×HO and HO steers were fed for 290 and 332-d, while 20CS and 40CS steers were fed for 307 and 314-d, respectively. There were no significant interactions between breed type and diet factors. The B×HO steers had a greater ADG, DMI, and gain:feed (P ≤ 0.01) compared with the HO steers. Dietary treatment did not affect performance metrics, except for DMI, which tended to be greater (P = 0.07) for steers fed 40CS than 20CS. Cost of gain was similar regardless of breed type and diet (P ≥ 0.68). Final live BW and hot carcass weight were greater for B×HO compared with HO (P ≤ 0.01) steers, but did not differ due to diet (P ≥ 0.19). Dressing percentage tended to be greater for B×HO compared with HO (P = 0.07) and was greater for steers fed 20CS compared with 40CS (P = 0.01). Liver abscess incidence was greater in HO compared with B×HO steers (49.2% vs. 21.7%; P < 0.01) and steers fed 20CS compared with 40CS (51.6% vs. 18.7%; P < 0.01). Additionally, B×HO carcasses had greater backfat thickness (P < 0.01) and greater longissimus muscle area (P < 0.01), but lesser kidney, pelvic, and heart fat percentage (P < 0.01), resulting in a lesser calculated USDA Yield Grade (P = 0.01) compared with HO carcasses. Carcass EBF, marbling score, and USDA Quality Grade were similar for breed type and diet (P ≥ 0.38). Carcass revenue was greater for B×HO carcasses when compared with HO carcasses (P = 0.04). Calculated breakeven value was $281/feeder calf greater for B×HO than HO (P = 0.02). Carcass revenue and breakeven feeder calf value were similar between diets (P ≥ 0.74). Overall, B×HO steers were more feed efficient, had a lesser incidence of liver abscesses, and produced carcasses with more desirable carcass yield, resulting in a greater breakeven feeder calf value compared with HO steers. Additionally, increasing corn silage inclusion from 20% to 40% reduced liver abscess incidence in both breed types without significantly influencing cost of gain.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"8 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PSX-23 Use of unmanned aerial vehicle technologies to assess nutrient landscape of cattle pens managed with energy dense vs. low energy feeding programs.","authors":"Logan E Diller, Haley E Larson, Logan R Thompson, Dale A Blasi","doi":"10.1093/jas/skaf300.593","DOIUrl":"https://doi.org/10.1093/jas/skaf300.593","url":null,"abstract":"An experiment was conducted to determine if feedlot pen conditions can be detected using unmanned aerial vehicle (UAV) technologies. Steers fed an energy-dense limit-fed diet or low-energy ad-libitum-fed diet were used to create a gradient in pen nutrient landscapes. The objectives were (1) characterize direct measurements to describe the landscape of cattle pens managed with energy-dense or low-energy feeding programs, and (2) evaluate the association of thermal images taken using UAV technologies with the nutrient landscape of feedlot pens. Dirt floor feedlot pens (n=6) (9.1 m x 15.2 m) stocked with 14 dairy-beef crossbred steers (avg. BW = 453.6 kg) at the Kansas State University Stocker Unit (Manhattan, KS) were used in the study. Two feeding programs were applied to the pens: 1) energy-dense 64 NEg limit-fed ration (n=3) and 2) low-energy 50 NEg ad libitum fed ration (n=3). Prior to data collection, pens were gridded into 15 quadrants (3 m x 3 m). Pen quadrants were further classified into pen regions. During the first daily feeding, a UAV (DJI M300) equipped with a thermal sensor (H20T) was flown over each pen (30 m altitude) to capture images. Images were processed using Pix4D, visualized using ArcGIS, and Photoshop was used to obtain color values (luminance) for each quadrant using 3 random sampling points. Within each pen, 3 pen floor grab samples (250 g) and 3 direct temperature measurements were taken from random locations within each quadrant and analyzed for moisture, ash, NDF, and ADF. Linear mixed-effects models were used to evaluate the effect of feeding program, pen region, and feeding program by pen region for each direct measurement (moisture, ash, moisture:ash, NDF, ADF, direct temperature, luminance). Differences in direct measurements across physical locations within feedlot pen by feeding program were identified for moisture (P< 0.01), moisture:ash (P< 0.01), direct temperature (P< 0.01), luminance (P< 0.01), ADF (P< 0.01), and NDF (P< 0.01). A trend (P=0.10) for an association between pen region and feeding program for ash was observed. Direct measurements with identified differences (P< 0.05) across the pen regions by feeding program were then tested for association by pen region to luminance using linear mixed-effects models. Results indicate a significant relationship between luminance and all direct measurement variables (P< 0.05). Lin’s concordance correlation coefficient was used to understand precision and accuracy between direct measurement variables and luminance. Moisture demonstrates good accuracy and precision (CCC=0.82) when predicted from luminance values. Results indicate moisture can be used to characterize pen landscape from UAV thermal images.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"157 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PSXIII-21 Animal performance and reproductive development in heifers fed with r-zeta® in high-concentrate diets.","authors":"Juan Sebastian Vittone, Maria Eugenia Munilla","doi":"10.1093/jas/skaf300.712","DOIUrl":"https://doi.org/10.1093/jas/skaf300.712","url":null,"abstract":"Nutritional management in replacements heifer is important to optimize the profitability of livestock farms. Food resources with high conversion rates offered in self-feeders achieve efficiency with easy management. It´s possible that the use of high-concentrate diets with the inclusion of additive to regulate intake contributes to increase animal performance and reproductive development in heifers. The aim of this work was to evaluate different rearing diet strategies with r-zeta® additive on replacements heifer performance and reproductive. One hundred twenty Hereford heifers (9,1± 1,7 month and 192,6 ± 19,0 kg body weight -BW-) were assigned to different treatments according to different diets to evaluate r-zeta® additive that regulate intake and modulate the ruminal microbiota. The defined treatments were HR+CS (hay roll and daily control supplementation at 1% BW); HR+Sr-zeta® (hay roll and daily balanced pellet r-zeta® supplementation at 1% BW); HR+SFr-zeta® (hay roll and self-feeding balanced pellet r-zeta®) and SFr-zeta® (self-feeding balanced pellet r-zeta®). In treatments with supplementation, ration was offered in linear feed bunks (daily supply) and in treatments with self-feeders was offered weekly. Triticale hay rolls were offered ad libitum. The control supplement and the balanced pellet were formulated with 36% PC/kg DM and 2.4 Mcal ME/kg DM. And the hay roll had 7.9% PC/kg DM and 1.3 Mcal ME/kg DM. The BW were used to adjust the supplement supply in the treatments HR+CS and HR+Sr-zeta®. Average daily gain (ADG), dry matter intake (DMI) and conversion (C) were estimated. Reproductive tract scoring (RTS) was measured at the final of the experience (day 83) and each heifer was scored from 1 (prepubertal) to 5 (cyclic). Data were performed using Infostat. The continuous variables studied were analyzed by ANOVA and RTS was compared by using a chi-square analysis. Significant differences were considered at p≤ 0.05. Heifers fed with r-zeta® in treatments with balanced pellet offered in self-feeders had higher ADG regarding those supplemented (1.2 vs. 0,7 kg/d). Total DMI (% LW) was lower in SFr-zeta® regardless to other treatments (2.4 vs. 2.6 to 2.8 % LW). In this sense, best conversion was in treatments with self-feeding balanced pellet with r-zeta® regardless of hay roll inclusion (Table 1). Finally, treatments with inclusion of the multifactorial additive had a higher proportion of heifers with good reproductive development (RTS 4 and 5). In the HR+CS, only 13% of the animals had this condition while in the HR+Sr-zeta®, HR+SFr-zeta® and SFr-zeta®, the 30, 39 and 37% were into RTS 4 and 5. In conclusion, r-zeta® additive in high-concentrate diets could be a strategy to use in raising heifers to improve their growth and reproductive development.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"8 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}