Journal of animal science最新文献

{"title":"242. Behavioral and Physiological Indicators of Litter Outcome in Gestating Gilts.","authors":"Andrea M Luttman, Nancy E Raney, Catherine W Ernst","doi":"10.1093/jas/skag272.314","DOIUrl":"https://doi.org/10.1093/jas/skag272.314","url":null,"abstract":"With rapid development and integration of precision technologies on swine farms, research is needed to identify behavioral indicators of productivity to inform these technologies and translate data into management recommendations. Biological relevance of postural behaviors that are common in automated identification and tracking is largely unknown. The objective of this study was to investigate salivary biomarkers and postural behavior in gestating gilts as potential indicators of farrowing outcomes. To achieve this, 16 gilts were housed in 4 pens of free-access stalls (n = 4/pen). Gilts were unlocked from the stalls, initiating social mixing, at 30 days of gestation (dg) and maintained as stable groups for the remaining gestational period. Saliva was collected by allowing the gilts to passively chew on ropes at 30 and 90 dg. Overhead, continuous video was recorded from 12:00 – 20:00 h at 30 and 90 dg. Recorded video was manually decoded for gilt location (pen, stall) and posture using instantaneous scans at 1 min intervals for a total of 480 scans per timepoint and 960 scans overall. Salivary cortisol, testosterone, and progesterone were quantified using commercially available ELISA kits. Farrowing outcomes recorded for each litter included total number born (TNB), number born alive (NBA), stillbirths, mummies, overlays, litter birth weight (LBW), average birth weight, birth weight standard deviation as a measure of piglet uniformity, number weaned, and litter wean weight (LWW). Greater kneeling behavior at 30 dg was significantly correlated with incidence of farrowing mummies (R = 0.75, P = 0.008, FDR = 0.012). At 90 dg, kneeling behavior was positively correlated with overlaying (R = 0.70, P = 0.005, FDR = 0.069). Sitting behavior at 90 dg was positively correlated with farrowing mummies and negatively correlated with number weaned (R = 0.74, P = 0.002, FDR = 0.042; R = -0.77, P = 0.001, FDR = 0.030, respectively). Each of these relationships remained significant after correcting for TNB. Gilts that spent more time lying sternal as opposed to lateral at 30 dg had less uniform piglets (R = 0.70, P = 0.008, FDR = 0.069). Similarly, sternal lying at 90 dg was negatively correlated with number weaned and LWW (R = -0.74, P = 0.002, FDR = 0.042; R = -0.72, P = 0.004, FDR = 0.063, respectively). There were no correlations detected between postural behaviors and salivary biomarkers, or between salivary biomarkers and farrowing outcomes. Nonetheless, these data suggest that kneeling and sitting behavior in gestating gilts are promising behavioral indicators of at-risk litters, and excessive sternal lying may be indicative of gilts that will be poor producers. As technology is already able to detect and differentiate between postural behaviors, this data provides insights for development of future precision tools for management and gilt selection.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"10 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077526","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":"PS2-6. Increasing Supply of omega-6 Fatty Acids to Beef Cows During the Early Embryonic Period: Effects on D 22 Pregnancies.","authors":"Izadora de Souza, Reinaldo F Cooke, Camila Prado, Thainá Minela, Zachary K Seekford, Brette Poliakiwski, Damon Smith, Ky G Pohler","doi":"10.1093/jas/skag272.540","DOIUrl":"https://doi.org/10.1093/jas/skag272.540","url":null,"abstract":"This experiment compared hormonal, uterine, and conceptus factors associated with pregnancy establishment in beef cows supplemented with different levels of Ca salts of soybean oil (CSSO) for 22 d beginning after artificial insemination (AI). Sixty-six multiparous, non-lactating Angus-influenced cows were allocated to 11 pens equipped with Calan-gate feeders (6 cows/pen), and timed-inseminated on d 0. After AI, cows were ranked by expression of estrus, body weight, and body condition score, and assigned to receive 1 of the 4 treatments: a) 100 g/d of CSSO (n = 16), b) 250 g/d of CSSO (n = 17), c) 100 g/d of Ca salts of palm oil (CON; n = 16), d) 250 g/d of CON (n = 17). Treatments were mixed with 0.5 kg of corn, and individually fed to cows daily using the Calan-gate feeders. Cows received ad libitum access to hay, mineral mix, and water. Blood samples were collected and transrectal ultrasonography was performed to verify ovulation and corpus luteum (CL) volume immediately before AI (d 0), on d 7, 14, and 21. All cows were slaughtered on d 22 for collection of conceptus and uterine luminal flushing. Fatty acid (FA) source × dose interactions (P ≤ 0.05) were detected for plasma concentrations of linoleic and total omega-6 FA, which were similar (P ≥ 0.55) between CON at 100 or 250 g/d, greater (P ≤ 0.05) in CSSO at 100 g/d compared with both CON treatments, and greater (P ≤ 0.05) in CSSO at 250 g/d compared with all treatments. No FA source nor FA dose effects were detected (P ≥ 0.12) for plasma progesterone concentrations and CL volume during the experiment, as well as proportion of cows with a conceptus. Within cows that had a conceptus, cows supplemented with CSSO had heavier (P = 0.04) conceptuses, and tended to have greater concentration of prostaglandin F2α in the uterine flushing media compared with CON cows (FA source effect), whereas dose effects were not detected (P ≥ 0.22) for these variables. No FA source nor FA dose effects were detected (P ≥ 0.17) for concentrations of prostaglandin E2 in the uterine flushing media from cows that had a conceptus. Within cows that had a conceptus, CSSO-supplemented cows had greater (P ≤ 0.05) mean mRNA expression of myxovirus resistance 2 and interferon-stimulated gene 15 in whole blood, whereas a tendency for a similar outcome was observed for mean mRNA expression of 20,50-oligoadenylate synthetase compared with CON-supplemented cows. No dose effects were detected (P ≥ 0.37) for mRNA expression of these genes in whole blood. In summary, post-AI CSSO supplementation increased plasma concentrations of omega-6 FA and improved factors associated with maternal recognition of pregnancy on d 22 of gestation.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"53 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077570","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":"PS5-7. In-situ Evaluation of Forage Grown in Soil Amended with Manure from Cattle Fed Different Types of Biochar.","authors":"Lauren Orlando, Kim Boardman, Samira Islas Valdez, Nicole Wagner, Merritt L Drewery","doi":"10.1093/jas/skag272.389","DOIUrl":"https://doi.org/10.1093/jas/skag272.389","url":null,"abstract":"Biochar is produced by pyrolyzing organic materials - primarily agricultural or forestry waste - at high temperatures (400-800 °C) under low-oxygen conditions, yielding a carbon-rich product with a large surface area. Biochar has been investigated as a soil amendment to improve soil health and promote plant growth; however, its incorporation into soil can be labor-intensive. As biochar passes through the gastrointestinal tract mainly intact, there is potential to feed it to grazing cattle, which then inoculate it with rumen microbes and deposit it with manure. However, there remains a deficit of research investigating the effects of biochar-amended manure on plant growth and quality for ruminant animals. The objective of this study was to evaluate how manure from cattle fed different types of biochar affects forage growth and rumen degradability. Beef steers (n = 5) consuming ad libitum forage were provided one of five treatments at 1.6% of the previous 3-d intake for 7-d: no biochar (CON); and biochar derived from pecan shells (PEC), bamboo (BB), mixed brush (MB), or pine (PN). Manure was collected from each steer over a 48-h period and mixed with native soil at a 0.02:1 ratio. Rye grass was grown in manure/soil mixtures, in soil treated with organic fertilizers (ORG), or soil without manure or organic fertilizers (SOL) for seven treatments total. Rye grass was harvested at 2.5 cm (grazing length), dried, ground, and ruminally incubated in cannulated beef steers (n = 3, 625.2 ± 97.9 kg) consuming ad libitum hay and receiving CSM (0.5 kg/d) in reverse order for 0, 4, 6, 12, 24, 48, and 72 h. Upon removal, bags were rinsed and dried at 55 °C for 96 h then air-equilibrated for 24 h to determine partial dry matter (PDM). Dry yields of rye grass were affected by treatment such that there were significant differences (P ≤ 0.05) between yields for biochar/manure-based treatments (25.9 ± 4.57 g) versus SOL (6.83 ± 2.56 g) and ORG (4.33 ± 1.63 g), but there were no differences across the various biochar/manure treatments or for SOL versus ORG. There were not adequate quantities of rye grass from SOL or ORG for in situ analysis. Across biochar/manure treatments, there were no differences in fractions of rye grass categorized as Instantly Degradable (18.1%; P = 0.98), Potentially Degradable (70.3%; P = 0.42), or Undegradable (11.6%; P = 0.13). Treatment also did not affect rate of degradability (kd; P = 0.30), which averaged 5.3%/h, or partial DM degradability (PDMD; P = 0.31). However, there were numerical differences in PDMD that may translate to biologically meaningful differences - i.e., MBB had lower PDMD (42.8%) than CON (50.1%) which was lower than MBP (58.2%), MBM (59.6%), and MBS (60.0%). These findings suggest that manure enhances rye grass yield and the presence of biochar within manure may enhance rumen degradability.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"17 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077675","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":"PS10-20. Effect of Sesame Plant Silage Level on In Vitro Digestibility, Ruminal Fermentation, and Methane Production.","authors":"Luis Corona Gochi, Karla Ximena Ávila-Juárez, Esteban Julián Mireles-Martínez, José Alonso-Galeana, Sebastián Mata-Cruz, José Moises Talamantes-Gómez, Águeda García-Pérez, Claudia Márquez-Mota, María Fernanda Vázquez-Carrillo, Armir Romero-Pérez","doi":"10.1093/jas/skag272.575","DOIUrl":"https://doi.org/10.1093/jas/skag272.575","url":null,"abstract":"The objective was to evaluate the inclusion of sesame plant silage (SPS) in a tropical grass-based diet using an in vitro gas production test, determining in vitro dry matter digestibility (IVDMD) and methane gas production. The base diet was Brachiaria sp. hay, with SPS substituted at 0%, 20%, 40%, 60%, 80%, and 100%. 0.5 g of substrate was placed in 4 x 10 cm nylon bags with 24 µm pores. These bags were deposited into 120 mL amber bottles. A completely randomized block design was used, with three flasks (replicates) per experimental treatment and per incubation, over three runs (blocks). Rumen contents were obtained from four Holstein cows and filtered through four layers of gauze. The rumen fluid was mixed with buffer according to the method of Menke and Steingass (1988). The flasks were placed in a 39 °C water bath. Gas production and pressure were recorded at 0, 3, 6, 9, 12, 18, 24, 36, 42, 48, and 72 hours using a digital manometer (Traceable®, Fisher Scientific). Gas samples were collected using a 50 mL syringe and transferred to vacuum flasks for later methane determination using an infrared detector (Gas-Pro Crowcon). Samples were analyzed for NH3-N and volatile fatty acids (VFAs) by gas chromatography. Fermentation kinetics were obtained by converting gas pressure to volume using the equation y = 7.0245x - 1.0849 (R² = 0.989), where y is gas volume and x is gas pressure (PSI). The fractional degradation rate (S, h), lag phase, and maximum gas production volume (Vmax) were calculated. Data were analyzed with a randomized complete block design in SAS MIXED. Mean comparisons used Tukey's test and orthogonal polynomials for the SPS level. For fermentation kinetics and IVDMD (Table 1), increasing SPS inclusion increased IVDMD up to 80% (quadratic effect, p < 0.01), after which it decreased. Vmax decreased (linear effect, P < 0.01) and S increased (linear effect, P < 0.01) as SPS increased. Table 2 shows that increasing SPS resulted in a linear decrease (P < 0.05) in all methane variables, reaching a 50% reduction at 100% SPS. This is mainly due to the sesame plant's oil content of 14% (DB). The IVDMD improves to 80% SPS, resulting in a 32% reduction in methane. Therefore, SPS offers a sustainable alternative in tropical areas for improving dietary digestibility and reducing methane emissions. This study was partially funded by the PAPIIT TA200625 project of the DGAPA, UNAM. For image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"16 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077900","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":"193. Increasing Organic Trace Mineral Supplementation During Late Gestation and Lactation Influences Sow Iron Status and Litter Weaning Performance in Prolific Sows.","authors":"Katlyn A McClellan, Darcy Pamulaklakin, Courtney Pohlen, Joshua Jendza, Eric M Weaver","doi":"10.1093/jas/skag272.167","DOIUrl":"https://doi.org/10.1093/jas/skag272.167","url":null,"abstract":"The objective of this study was to evaluate the effects of increasing dietary TM supplementation during late gestation and lactation on reproductive performance and sow and progeny iron status. Forty-five sows (parity 0–4) at 70 ± 2 d of gestation were alloted by parity, body weight (BW), and blood hemoglobin (Hb) and assigned to one of four dietary treatments: 1) control with no supplemental TM (CON), 2) TM supplied at NRC (2012) estimated requirements (NRC), 3) 2 × NRC TM levels (2×NRC), or 4) 3 × NRC TM levels (3×NRC). Trace minerals were supplied in organic forms, with zinc, iron, copper, and manganese provided as polysaccharide-complexed sources. Selenium inclusion was constrained to remain within established regulatory limits across all treatments. Sow blood samples and BWs were collected on d 70, 90, and 110 of gestation and on d 2 of lactation and at weaning (lactation d 20 ± 3). Piglets were weighed and tested for Hb at birth (N = 732) and weaning (N = 639). Blood samples were collected from two piglets per litter (n = 140) at 40–48 h after birth and again at weaning. Data was analyzed using PROC MIXED (SAS 9.4) with dietary treatment as a fixed effect and sow as a random effect, and orthogonal polynomial contrasts were used to evaluate quadratic responses to increasing TM supplementation. Day 90 gestation sow Hb responded quadratically to increasing trace mineral supplementation (CON: 11.6 g/dL; NRC: 11.7 g/dL; 2xNRC: 12.8 g/dL; 3xNRC: 12.2 g/dL, quadratic: P = 0.076), with the fitted model estimating maximal Hb concentration at 2.4 × NRC recommendations. Predicted peak Hb concentration at the estimated optimum was 12.4 g/dL. Reproductive traits, including total born, liveborn, stillborn percentage, and farrowing duration, as well as sow BW, were not affected by treatment. Number of pigs weaned increased and then decreased (quadratic, P = 0.014) as TM supplementation increased (CON: 12.91; NRC: 14.72; 2xNRC: 15.00; 3xNRC: 14.17). Piglet wean weights tended to be greater in the 2xNRC (6.34kg) than the other treatment groups (CON: 5.71kg; NRC: 5.59 kg; 3xNRC: 5.61kg; P = 0.091). Total litter wean weight exhibited a quadratic response to increasing TM supplementation (CON: 76.78 kg ; NRC: 80.31kg; 2xNRC: 91.15kg; 3xNRC: 79.56kg, quadratic: P = 0.072), with the fitted model estimating maximal litter wean weight at approximately 1.75 × NRC recommendations. The predicted litter wean weight at the estimated optimum was 86.9 kg. In conclusion, maternal Hb concentration and litter wean weight were optimized at different organic TM inclusion levels, suggesting that supplementation at 1.75 to 2.0 × NRC TM estimated requirements supports maternal iron status without compromising litter growth performance.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"23 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149078011","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":"349. Award Talk: Effects of Betaine Supplementation and Nutrient Restriction During Gestation Onfetal Muscle Development and Oxidative Status in Sheep.","authors":"Santhi Priya Voggu, Nicole M Tillquist, Cheyenne S Summers, Kaitlyn Baran, Nicholas Barnello, Manda S Reiter, Mia Y Kawaida, Sarah A Reed, Steven A Zinn, Kristen E Govoni","doi":"10.1093/jas/skag272.137","DOIUrl":"https://doi.org/10.1093/jas/skag272.137","url":null,"abstract":"Maternal nutritional status during gestation impacts fetal myogenesis and liver oxidative balance, thereby altering growth and metabolic function. Supplementation of betaine, a methyl donor, supports muscle development and antioxidant capacity, and improves physiological responses. We hypothesized that maternal nutrient restriction during gestation would impair fetal muscle development and alter fetal liver antioxidant status, while betaine supplementation would alleviate the negative effects of maternal nutrient restriction. To test this hypothesis, 32 multiparous Dorset ewes were estrus-synchronized and bred to one of three related rams. Ewes pregnant with twins were assigned to one of four diets [100% NRC requirements (CON), 60% NRC (RES), CON+betaine (CON+BET; 2 g/day), and RES+BET] from day 30 to 130 of gestation. The offspring included 27 males (CON:8, RES:5, CON+BET:5, RES+BET:9) and 37 females (CON:8, RES:9, CON+BET:11, RES+BET:9). Maternal blood was collected on days 30 and 130 of gestation, and at necropsy on day 130, fetal semitendinosus (STN) and longissimus dorsi (LM) muscles, and liver were collected for immunohistochemistry and oxidative status, respectively. Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were measured in maternal plasma and fetal liver isolates using commercially available assay kits. Data were analyzed using RStudio with ANOVA, including fetal sex as a covariate, with P ≤ 0.05 considered significant and 0.05 < P ≤ 0.10 as a tendency. In fetal STN, the percentage of Pax7-positive cells was reduced in RES compared with CON and RES+BET (P ≤ 0.01). In contrast, the percentage of Pax7-positive cells in the LM was not affected by maternal diet (P = 0.65). Male fetuses from RES ewes had greater type I and fewer type II fibers compared with RES+BET males in STN (P = 0.03). Maternal plasma MDA concentration, SOD, and GPx activities did not differ among diet groups at day 30 of gestation (P ≥ 0.20). At day 130, maternal plasma GPx activity tended to be reduced in RES+BET (5.86±1.12 U/mL) compared with CON+BET (10.26±1.28 U/mL; P = 0.08), while MDA and SOD were not different (P ≥ 0.64). Fetal liver SOD and GPx activities were greater in CON (40±1.95 and 74.5±3.55 U/mg protein, respectively) and CON+BET (35.7±2.18 and 77±4.13 U/mg protein) than in RES (27±2.64 and 58±4.16 U/mg protein) and RES+BET (29±1.90 and 63±3.70 U/mg protein; P ≤ 0.001). Fetal liver MDA concentrations were not affected by maternal diet but tended to be greater in males (0.133±0.007 nmol/mg protein) than females (0.114±0.006 nmol/mg protein; P = 0.06). Overall, maternal nutrient restriction altered fetal muscle development and liver antioxidant capacity, with betaine supplementation providing partial, tissue specific responses, highlighting the need for further study of betaine as a targeted nutritional intervention during maternal nutrient restriction.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"17 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077525","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":"268. Copper Deficiency of Cool-Season Invaded Grassland Affects Liver Mineral Content of Growing Beef Heifers.","authors":"Rachael G Christensen","doi":"10.1093/jas/skag272.125","DOIUrl":"https://doi.org/10.1093/jas/skag272.125","url":null,"abstract":"Yearling beef heifers grazing grasslands often exhibit outward signs of copper (Cu) deficiency, including poor coat color, dulled hair and weakened immune response, indicating inefficiencies in growth and production. We utilized a 2 by 2 factorial study to compare liver mineral concentration and weight gain of yearling heifers (Bos taurus) receiving one of two types of Cu supplement (amino acid complexed copper vs. copper chloride) and grazing on cool-season dominated pastures that were managed two different ways (rested one or more years prior to grazing vs grazed yearly). Three different pastures were split in 4 paddock strips, with two assigned for organic supplementation and two for inorganic supplementation of copper with a group of 3 heifers (blocked by weight) grazing in each sub paddock. Pastures contained primarily smooth bromegrass (Bromus inermis Leyss.), Kentucky bluegrass (Poa pratensis L.), western wheatgrass [ Pascopyrum smithii (Rydb.) A. Liive], needle and thread (Stipa comata Trin. and Rupr.), green needlegrass (S. viridula Trin.), blue grama [Bouteloua gracilis(Willd.ex Kunth) Lag. Ex Griffiths] and upland sedges (Carex spp.). Liver samples were collected before and after grazing the trial pastures for 6 wk. for two years, while due to drought conditions, a smaller group of cattle were grazed the other two years. Therefore, four years of weekly forage samples and biomass data were collected but only two years of biopsied liver, forage and mineral consumption, and weight data. Heifers were supplemented with loose mineral supplying 168 mg Cu hd-1d-1. Liver Cu concentration in the pre-trial sampling averaged 29 ±21.01 mg/g DW for both groups. Post trial liver Cu was increased 35 mg/g DW for heifers receiving amino-acid complexed copper, and 29.8 mg/g DW for those on inorganic sources, but the difference was not significant and was not affected by pasture management (P = 0.56). Forage samples did not demonstrate differences in Cu concentration due to management. There were also no differences in body weight increase between amino acid Cu- supplemented and Cu-chloride supplemented heifers during the grazing season. Average daily gain was significantly different due to year (0.65 kg the first year and 0.46 kg, P = 0.02 the next year) but not affected by copper source or pasture management. The most consistent benefit from Cu supplementation was an increase in liver copper concentration regardless of copper source. Forage values indicate that grassland forages are marginal to deficient in Cu for optimal development of beef heifers and supplementation is necessary, with amino-acid chelated Cu heifers posing a marginally greater Cu content in liver.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"112 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077600","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":"PS6-8. High Fat Milk Replacers Promote Early Marbling Development in Angus X Holstein Calf Ribeyes.","authors":"Perri Gish, Logan Rosenberg, Lucas Smith, Payam Vahmani","doi":"10.1093/jas/skag272.394","DOIUrl":"https://doi.org/10.1093/jas/skag272.394","url":null,"abstract":"Beef-on-dairy calves raised at calf ranches are fed milk replacer during the pre-weaning stage, creating opportunities to promote enhanced muscle and marbling development through early-life nutritional interventions. The objective of this study was to measure how dietary energy source affects skeletal muscle development in beef-on-dairy calves. 16 same-sire Holstein x Angus calves were assigned to either a high-fat (HF, 34% lactose and 30% crude fat) or high-lactose (HL, 50% lactose and 18% crude fat) diet on day 1 of life, and calves were fed their respective milk replacer on a step-up step-down feeding schedule for 50 days. Diets were isonitrogenous and fed at 150g/L (HL) or 132g/L to ensure an isocaloric intake; chopped wheat straw and water were offered ab libitum. Fecal and respiratory scores were taken daily, all feed refusals were measured, and weight was recorded weekly. Calves were slaughtered at 50 ± 3 days of age and the right longissimus thoracis (ribeye) was frozen at -20 °C for later meat quality assessment. Samples from the left ribeye and brisket were flash frozen in liquid nitrogen and stored at -80 °C until cryosectioning. For meat quality assessment, collected ribeyes were thawed in a low cooler until 3 °C and measured using a colorimeter. Warner-Bratzler shear force was performed parallel to muscle fibers on triplicate cooked ribeye cores using a 1000N load cell. For ex vivo histology, flash frozen muscle was cryosectioned transversely and immunohistochemically stained for perilipin-1 to stain mature lipid membranes, PDGFRa to stain fibro-adipogenic progenitor cells (FAP) which predate marbling, and Ki67 to stain proliferating cells. Statistical analysis was performed using an unpaired t-test, and significance was set at p < 0.05 and trends at 0.05< p < 0.1. Both fecal and respiratory scores were not significantly different between treatment groups, and HF and HL calves had similar feed conversion ratios and average daily gains. HF ribeyes were significantly greener than HL, and HF trended to be more yellow in objective color measurement; shear force was not significantly impacted. HF ribeyes had a significantly higher fat:muscle ratio in the ribeye, but in the brisket HL samples has a higher fat:muscle ratio. Despite this finding, we found no significant difference between HL and HF FAP cell counts or their proliferation rates. This preliminary data shows that while health and performance is maintained between isocaloric diets, a dietary energy source of primarily fat promotes early marbling development in a muscle-specific manner within the first 50 days of life. However, the mechanism behind this remains unclear. Future work will further assess pro-meat quality muscle development and the systemic effects of dietary energy source.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"196 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077774","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":"PS1-22. Monensin, Narasin, and Their Alternation in High-concentrate Diets Do Not Accelerate Puberty in F1 (Angus × Nellore) Heifers.","authors":"Larissa Peroti Bello, Bismarck Soares Alexandrino, Mariana Jeronymo, Pedro Henrique de Lima Salmaso, Mirela B Balistrieri Dias, Bárbara Martins Brixner, Daniel Montanher Polizel, Diogo Fleury Azevedo Costa, Flávio Augusto Portela Santos, Alexandre Vaz Pires","doi":"10.1093/jas/skag272.570","DOIUrl":"https://doi.org/10.1093/jas/skag272.570","url":null,"abstract":"Age at puberty and age at first calving are key determinants of efficiency in beef production systems. Earlier reproductive maturity allows heifers to calve sooner and remain productive for a longer period, increasing lifetime productivity. Puberty onset is influenced by the interaction between genetic background and nutritional management during the pre-pubertal growth phase. Nutritional strategies that enhance body development during this stage may contribute to earlier reproductive maturity. In this context, feedlot systems combined with feed additives that improve dietary energy utilization could potentially promote earlier puberty. Therefore, we hypothesized that feedlotting pre-pubertal heifers associated with ionophore supplementation would enhance body development and advance the onset of puberty. Forty F1 (Angus × Nellore) heifers were used in this study. At the beginning of the experiment, animals averaged 210 ± 16.95 kg of body weight and were approximately 8 months of age. Heifers were assigned to a randomized complete block design according to initial body weight. Treatments consisted of: (1) CON = basal diet without additive; (2) MON = CON diet plus 25 ppm monensin; (3) NARA = CON diet plus 13 ppm narasin; and (4) N+M = alternation between narasin (13 ppm) and monensin (25 ppm) at each experimental period. The experimental period lasted 154 days, including 14 days of dietary adaptation followed by 140 days of evaluation, divided into five 28-day experimental periods. Heifers were monitored for reproductive development by transrectal ultrasonography to detect corpus luteum (CL) formation. Evaluations began during the second experimental period and were conducted weekly, totaling 14 evaluations per animal throughout the study. The presence of a CL was used as an indicator of luteal activity, and heifers were considered pubertal on the day the structure was first detected. Growth performance was also monitored during the experimental period. Data were analyzed using the MIXED procedure of SAS, and treatment effects were considered significant at P ≤ 0.05. No treatment effects were observed for age at puberty (P = 0.75), body weight at puberty (P = 0.87), average daily gain until puberty (P = 0.73), or corpus luteum diameter (P = 0.19). At the end of the experimental period, all heifers in the control treatment reached puberty, whereas approximately 80% of heifers receiving ionophores (MON, NARA, and N+M) presented a corpus luteum. These results indicate that ionophore supplementation during feedlot development did not accelerate puberty in F1 Angus × Nellore heifers. However, the feedlot system allowed early identification of heifers that reached puberty, which may support management decisions for replacement selection. Heifers that fail to reach puberty during this period may be redirected to finishing systems, whereas pubertal females may be retained as replacements, improving efficiency in beef production systems.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"40 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077898","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":"PS4-2. Triticale Silage Used as Ruminal in Situ Substrate to Assess the Effects of Saccharomyces Cerevisiae in Beef Cattle Grower and Finisher Diets.","authors":"Fernanda Berumen, Jhones O Sarturi, Ahmari D Henry, Brooke A McCrumb, Kaliu Scaranto Silva, Kip K Karges, Beatriz Q Dos Reis, Osman R A Melgar, Otavio France","doi":"10.1093/jas/skag272.413","DOIUrl":"https://doi.org/10.1093/jas/skag272.413","url":null,"abstract":"Ruminal degradability kinetics of triticale silage (in situ substrate) of beef steers consuming beef cattle grower and finisher diets with or without (live yeast) Saccharomyces cerevisiae were evaluated. Eight surgically prepared beef steers were used in a duplicated 4 × 4 Latin square design (four 38-day periods) following a 2 × 2 factorial arrangement of treatments: A) presence of live yeast (Saccharomyces cerevisiae [CNCM I-1077], at 1 × 1010 CFU/animal-daily); and B) diet type (steam-flaked corn-based grower or finisher diets [ad libitum intake]). Live yeast was delivered via gel capsules (0.25 g, as-is) twice daily through the ruminal cannula. Pre-dehydrated (55ºC for 72 h) triticale silage substrate was ground (2 mm) and placed into 10 × 20 cm (28 µm) nylon bags (5g, as-is). Bags were placed in the ruminal ventral sac within a nylon mesh (with weights) and reversely removed at 0, 2, 4, 8, 12, 20, 32, 48, 64, 72, and 96 h after incubation. Residue bags were rinsed and dehydrated for 72 h at 55ºC. Residue duplicates were composited, corrected for moisture, and used to fit a first-order kinetics model using the NLIN procedure of SAS. The GLIMMIX procedure of SAS was used with animals as the experimental unit, the fixed effects (diet, period, interaction), and the random effects of animal ID within square, square, and period. Live yeast inclusion tended (Diet × Yeast interaction, P = 0.06) to increase the rate of degradation and the effective degradability calculated at 4, 5, and 6 %/h of the substrate organic matter (OM) when offered in finisher diets, while not affecting such fractions in grower diets. Regardless of diet type, live yeast increased the substrate dry matter (DM) rate of degradation (P = 0.04), tended (P = 0.10) to increase the effective degradability of the DM fraction (calculated at 4%/h rate of passage), and tended (P = 0.11) to decrease the substrate hemicellulose fraction lag-time (h). Regardless of live yeast inclusion, steers offered the grower diet had greater (P < 0.01) triticale silage substrate potentially degradable fraction, lesser undegradable (P < 0.01), and greater (P < 0.01) effective degradability calculated at 4, 5, and 6 %/h rate of passage for DM, OM, NDF, ADF, and hemicellulose fractions, while also tending (P = 0.11) to increase the substrate DM rate of degradation compared to finisher diets. The current ruminal in situ model replicated expected results between beef cattle steam-flaked corn-based grower and finisher diets when using a forage substrate. Live yeast seemed to improve ruminal effective degradability of a high-quality forage substrate (triticale silage) OM fraction in a beef cattle finisher diet more intensively than in a grower diet, while other positive effects were observed regardless of diet type.","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":"10 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149077904","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}