Journal of animal science最新文献

{"title":"Genetic associations between pregnancy loss and economically important traits in Nellore cattle.","authors":"Flávia C Bis, João B Silva Neto, Ludmilla C Brunes, Leticia Pereira, Rafael Espigolan, Elisângela C de Mattos Oliveira, Angelica Pereira, José Bento S Ferraz, Fernando Baldi, Sabrina T Amorim","doi":"10.1093/jas/skag130","DOIUrl":"https://doi.org/10.1093/jas/skag130","url":null,"abstract":"<p><p>Pregnancy losses (PL) affect calf production and economic efficiency in beef cattle operations. Here, PL was defined as failure from pregnancy diagnosis to calving, capturing a window approximately 60 days after the breeding season. In Zebu breeds, the genetic understanding of this phenomenon remains limited. The objective of this study was to estimate genetic parameters for PL in Nellore heifers and its associations with reproductive, growth, feed efficiency, and carcass traits. The dataset comprised 23,507 Nellore heifers with pregnancy diagnosis records (17,052 genotyped) from the Animal Genetics and Breeding Program (GMA), developed by the Animal Breeding and Biotechnology Group (GMAB) at the University of São Paulo, Brazil. Variance components and genetic parameters were estimated using a two-trait threshold-threshold animal model for PL jointly with the probability of early calving at 30 months of age (PP30) and stayability (STAY), and a two-trait threshold-linear animal model for PL with age at first calving (AFC), scrotal circumference adjusted to 365 days (SC365), cumulative cow productivity (CCP), body weight adjusted to 240 (W240) and 455 days of age (W455), rib eye area (REA), rump fat thickness (RFT), marbling (MAR), residual feed intake (RFI), and dry matter intake (DMI). For all traits, the single-step GBLUP methodology was applied. The two-trait analyses were carried out using Bayesian inference through the Gibbs sampling algorithm implemented in the GIBBSF90+ software. The estimated heritability (h2) for PL was low (0.033), indicating strong environmental influence. Genetic correlations between PL and reproductive traits (PP30, STAY, AFC, CCP, and SC365) ranged from -0.15 to 0.93. For growth (W240 and W455) and carcass (REA, RFT, and MAR), genetic correlation ranged from -0.16 to 0.01. For RFI and DMI, genetic correlations were -0.44, and 0.07, respectively. The direct genetic gain for PL was of low magnitude. The relative efficiency of selection indicates that direct selection for PL tends to be less efficient than indirect selection. Therefore, the results of this study demonstrate that, although PL shows low h2, it is favorably correlated with sexual precocity in females. Selection for growth and carcass traits is not expected to affect PL, whereas the observed antagonistic correlation with RFI suggests a potential increase in PL among more feed-efficient animals, although this effect is small and not conclusive.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863768","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":"Stage-specific remodeling of WNT signaling during oocyte-to-embryo transition in pigs.","authors":"Carolina G Cabrera-Gomez, David Gascon-Collado, Paula Blanco-Cueto, Belen Pequeño, Heriberto Rodriguez-Martinez, Cristina A Martinez-Serrano","doi":"10.1093/jas/skag134","DOIUrl":"https://doi.org/10.1093/jas/skag134","url":null,"abstract":"<p><p>The WNT signaling pathway is a central regulator of cell polarity, adhesion, cytoskeletal dynamics, and lineage specification during early embryonic development. Although its roles have been extensively studied in murine and human models, the temporal regulation and pathway architecture of WNT signaling during early porcine development remain poorly defined. Here, we performed a comprehensive transcriptomic analysis to characterize WNT pathway dynamics across key stages of pig in vitro development, including immature oocytes (IMO), mature oocytes (MO), zygotes (ZY), cleaved embryos (2-4 cells; CL), and blastocysts (BL). Global analyses revealed major transcriptomic transitions (FDR < 0.05; |Fold Change| ≥ 2) during oocyte maturation and blastocyst formation, whereas zygotes and cleaved embryos exhibited highly similar expression profiles. Module-based and gene-level analyses showed that oocyte maturation is associated with increased expression of extracellular WNT antagonists and components of the β-catenin destruction complex, together with selective regulation of Frizzled receptors, consistent with tight control of canonical WNT signaling at the MII stage. Following fertilization, this inhibitory configuration was partially relieved, alongside transient upregulation of specific WNT ligands, transcriptional mediators, and adhesion-related components during zygotic genome activation and early cleavage. At the blastocyst stage, WNT signaling became increasingly associated with planar cell polarity and epithelial organization modules. Together, the data reveal a highly dynamic and stage-specific restructuring of WNT signaling during early porcine development. Our findings indicate that precise temporal modulation-rather than uniform activation-of WNT pathway components accompanies the porcine oocyte-to-embryo transition, providing a molecular framework to better understand early developmental regulation and offering insights relevant to reproductive biotechnology and developmental biology.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863986","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":"Reducing dietary protein in corn-soybean meal diets by reducing soybean meal and adding synthetic amino acids does not affect net energy or ileal starch digestibility, but increases ileal amino acid digestibility and reduces nitrogen retention.","authors":"Minoy Cristobal, Su A Lee, Carl M Parsons, Hans H Stein","doi":"10.1093/jas/skag129","DOIUrl":"https://doi.org/10.1093/jas/skag129","url":null,"abstract":"<p><p>Two experiments were conducted to test the hypothesis that diet protein concentration does not affect apparent ileal digestibility (AID) of starch, standardized ileal digestibility (SID) of amino acids (AA), daily nitrogen retention, or net energy (NE) in diets fed to growing pigs. In experiment 1, seven diets were used. A corn-SBM diet without synthetic AA was formulated to contain 17% CP. Five additional diets containing 14, 13, 12, 11, or 10% CP were formulated by reducing SBM and increasing corn and synthetic AA. A nitrogen-free diet was also used to determine basal endogenous losses of AA, and Cr2O3 was included in all diets as an indigestible marker. Seven barrows (initial body weight: 38.2 ± 1.5 kg) that had a T-cannula installed in the distal ileum were allotted to a 7 × 7 Latin square design with 7 diets and 7 periods, and ileal digesta were collected for 2 days of each period. Results indicated that AID of starch was not influenced by diet CP concentration, but SID of CP and all indispensable and dispensable AA increased (linear, P < 0.05) as dietary CP was reduced. In experiment 2, the six protein-containing diets from experiment 1 were used, but Cr2O3 was replaced by corn and no nitrogen-free diet was used in this experiment. Twenty-four growing pigs (initial BW: 29.9 ± 2.4 kg) were placed in 6 calorimeter chambers with 4 pigs per chamber. The 6 chambers were allotted to the six diets using a 6 × 6 Latin square design with 6 periods of 14 days. Pigs had ad libitum access to diets throughout the experiment except during the final 36 h of each period, when pigs were fasted. Net energy in diets was determined using indirect calorimetry. Results indicated that digestible energy, metabolizable energy, and daily nitrogen retention were reduced (linear, P < 0.05) as dietary CP was reduced, but NE in diets was not influenced by dietary CP. In conclusion, the hypothesis that reducing CP of diets for pigs by reducing SBM and increasing corn and synthetic AA does not affect AID of starch or NE of diets was confirmed, but the hypothesis that SID of indispensable AA and daily nitrogen retention is not affected by dietary protein concentration was rejected.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863996","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":"Perinatal short-chain fructo-oligosaccharide supplementation to sow affects colostrum quality, and consequently microbiota composition and performances of progeny.","authors":"Cindy Le Bourgot, Jeroen Degroote, Agathe Roméo, Maryam Majdeddin, Noémie Van Noten, Elout Van Liefferinge, Joris Michiels","doi":"10.1093/jas/skag140","DOIUrl":"https://doi.org/10.1093/jas/skag140","url":null,"abstract":"<p><p>Perinatal nutrition of the sow plays a decisive role in controlling gut bacterial primo-colonization in the offspring and, thereby, is an important driver of the development of piglets. Since short-chain fructo-oligosaccharides (scFOS) are known to positively modulate the gut microbiota composition and its fermentative activity, our study aimed at evaluating the effects of such supplementation to the sow during the perinatal period on nutritional and immune quality of colostrum and milk, and gut microbiota establishment, and subsequent consequences on growth performances of piglets. Sows received a control diet or a diet supplemented with either a low dose (Low scFOS) or moderate dose of scFOS (Mid scFOS): 0.15% or 0.33% from day 28 pre-partum to day 2 post-partum, then 0.10% or 0.15% until the end of the lactation period, respectively. At 23 days of age, piglets were weaned on a standard diet and followed for growth parameters until 67 days of age. The supplementation of scFOS in sow diet improved the nutritional composition of colostrum and its immune quality by increasing protein content (Low and Mid scFOS), IgG (Low scFOS) and TGF-β1 (Mid scFOS) concentrations. Few changes were recorded regarding the sow fecal microbiota composition while the short-chain fatty acids (SCFA) synthesis was significantly increased in Low scFOS group, with Mid scFOS group being intermediate. On the contrary, in neonates, significant changes in fecal microbiota composition were measured, while SCFA production was not different between groups. Some strains of Lactobacillus were greatly increased upon maternal scFOS supplementation. The modulation of the microbiota resulted in a significant reduction of feed conversion ratio in weaned pigs born from scFOS supplemented mothers. Our results demonstrated that scFOS addition in the maternal diet represents a beneficial nutritional strategy to improve the quality of colostrum and modulate the gut microbiota colonization, positively impacting feed efficiency of piglets.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147864001","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":"Genome-wide association studies for feed efficiency, production and feeding behaviour traits in Canadian purebred Duroc pigs.","authors":"Belle Kim, Duy Ngoc Do, Mohsen Jafarikia, Dan Tulpan, Deborah Adewole, Ghader Manafiazar, Brian Sullivan, Justin Holl, Younes Miar","doi":"10.1093/jas/skag148","DOIUrl":"https://doi.org/10.1093/jas/skag148","url":null,"abstract":"<p><p>This study aimed to identify potential genetic variants and candidate genes associated with feed efficiency (FE), production, and feeding behaviour traits in Canadian purebred Duroc pigs. Genome-wide association studies (GWAS) were conducted using 8,861 individuals and an imputed Affymetrix PigGen Canada 50K panel v2.0 using a linear mixed model (LMM) and a Bayesian B model. This analysis used an adjusted p-value threshold (ranging from 6.6 × 10-5 to 1.3 × 10-4) using false-discovery rate to determine significance. The number of significant SNPs identified for each trait was as follows: average daily gain (ADG, 48), daily feed intake (DFI, 85), feed conversion ratio (FCR, 101), residual feed intake (RFI, 37), residual gain (RG, 64), residual intake and gain (RIG, 55), backfat thickness (BF, 100), loin depth (LD, 6), Keibler ratio (KR, 0), total time spent eating per day (TPD, 7), and number of visits to the feeder per day (NVD, 6). Several traits (BF, DFI, FCR, RFI, RG, and RIG) showed strong overlapping signals on chromosomes 7 and 10 with 24 shared significant SNPs, indicating potential shared genetic mechanisms. These traits also had 71 overlapping candidate genes such as PACSIN1, PTCH1, ADIPOR1 and ITPR3, associated with glucose, lipid and cholesterol metabolism. Well known candidate genes in literature associated with growth and fatness such as MC4R and CDH20 were also identified to be associated with ADG, BF, FCR and DFI in this study. Gene Ontology enrichment analysis revealed a set of the candidate genes were involved in the gonadotropin-releasing hormone (GnRH) and the platelet-derived growth factor (PDGF) signaling pathways. Overall, this study contributed to understating the genetic architecture and provided a biological foundation for improving FE, production and feeding behaviour traits in Canadian Duroc pigs facilitating the selection of more efficient pigs.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863783","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":"Multivariate structure of semen quality and growth performance in Limousin beef bulls: a CoSTATIS approach.","authors":"Alberto Benito-Díaz, Purificación Vicente Galindo, María Anciones-Polo, Mónica Montañés Foz, Raúl Bodas Rodríguez, Juan José García García, Ainhoa Sarmiento-García","doi":"10.1093/jas/skag157","DOIUrl":"https://doi.org/10.1093/jas/skag157","url":null,"abstract":"<p><p>In beef bull evaluation, semen quality and growth performance are routinely assessed, yet their multivariate relationship has not been systematically characterized. The present work aimed to characterize the multivariate organization of semen quality and growth performance in Limousin bulls and to assess the extent of shared structure between these domains using a multi-year analytical framework. Semen quality, including sperm kinematics and sperm concentration (CON), and growth performance data were collected from 30 Limousin bulls evaluated over three consecutive years (2021-2023) under standardized performance testing conditions. Multivariate analyses were conducted using STATIS DUAL to identify stable internal structures within each block of variables and CoSTATIS to evaluate co-structure between reproductive and productive traits across years. STATIS DUAL revealed internally consistent multivariate structures for both semen quality and growth performance traits despite differences in annual animal cohorts. Semen quality traits were organized into coherent functional groups dominated by sperm kinematic parameters, whereas quantitative ejaculate traits such as CON formed a distinct structural component. CoSTATIS analysis showed that the co-structure between semen quality and growth performance was captured within a low-dimensional space, with the first two co-inertia axes explaining 94.94% of the total co-inertia (axis 1: 80.07%; axis 2: 14.87%). The shared structure was driven mainly by CON and curvilinear velocity (VCL), while most semen quality traits contributed weakly to the common space. These results indicate that semen quality and growth performance in Limousin bulls represent largely independent multivariate biological structures with only partial overlap, highlighting the importance of evaluating reproductive and productive traits as complementary but non-redundant components in breeding and performance testing programmes.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863762","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":"Evaluating fecal inflammation biomarkers for non-invasive detection of weaning-related intestinal inflammation in piglets.","authors":"Júlia Suppi, Eudald Llauradó-Calero, Jaume Coma, Anna Pelegrí-Pineda, Yolanda Saco, Anna Bassols, David Solà-Oriol","doi":"10.1093/jas/skag132","DOIUrl":"https://doi.org/10.1093/jas/skag132","url":null,"abstract":"<p><p>Post-weaning diarrhea remains a major challenge without noninvasive diagnostic tools. Fecal biomarkers represent a promising alternative, as they reflect gut inflammation without invasive sampling. This study evaluated four biomarkers-calprotectin (fCal), lipocalin-2 (LCN-2), myeloperoxidase (MPO), and adenosine deaminase (ADA)-using a zinc oxide (ZnO) model to assess their value as gut-health indicators in piglets. 384 weaned piglets (23 days) were assigned to two diets: Control and ZnO-supplemented (1 g/kg feed). Piglets were weighed on days 0, 3, 8, and 14. On days 3 and 14, nine average-weight piglets per group were sampled for feces and intestinal tissue. fCal was measured by immunoturbidimetry, MPO by o-dianisidine oxidation, ADA by enzymatic colorimetry, and LCN-2 by ELISA. Microbiota was analyzed by 16S sequencing and tissues by qPCR and histology. On day 3, ZnO piglets showed fewer intraepithelial lymphocytes (P = 0.062), higher IL-10 expression (P = 0.029), and lower Escherichia-Shigella abundance (P = 0.045). By day 14, they were ∼300 g heavier (P = 0.071), had higher villus-to-crypt ratios (P = 0.026), maintained IL-10 upregulation (P = 0.083), and increased OCLN expression (P < 0.001). Their microbiota shifted toward Odoribacter and Akkermansia (P ≤ 0.002), with reductions in Clostridium sensu stricto 1 (P < 0.001). fCal and LCN-2 were reduced in the ZnO group on day 3 (P ≤ 0.002), but only fCal remained reduced by day 14 (P = 0.012). No diet effects were observed for MPO or ADA (P > 0.05). On day 3, fCal correlated with CRHR1 (R = 0.59, P = 0.025) and negatively with barrier-related genes MUC13 and OCLN (R ≤ -0.50, P ≤ 0.050). MPO tended to correlate with CRHR1, crypt depth (R ≥ 0.44, P ≤ 0.069), and Streptococcus abundance (R = 0.45, P = 0.073). LCN-2 was negatively associated with inflammatory genes such as TNF-α and NF-κB (R ≤ -0.55, P ≤ 0.041). ADA showed positive trends with potentially pathogenic phyla, such as Campilobacterota (R ≥ 0.43, P ≤ 0.084). By day 14, fCal, LCN-2, and MPO were correlated with immune-related genes (e.g., TNF-α, TGF-β; R ≥ 0.52, P ≤ 0.071), while ADA was associated with the stress-related gene HSD11B1 (R = 0.74, P = 0.002). Overall, fecal biomarkers were valuable indicators of post-weaning gut inflammation and barrier function. Specifically, fCal was the most consistent, LCN-2 and MPO may serve complementary roles, whereas ADA primarily reflected cellular stress rather than inflammation.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147864146","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":"Estimation of genetic parameters for heifer pregnancy and carcass traits in Angus cattle.","authors":"Sarah L Phelps, Miranda M Culbertson","doi":"10.1093/jas/skag139","DOIUrl":"https://doi.org/10.1093/jas/skag139","url":null,"abstract":"<p><p>The genetic relationship between heifer pregnancy (HP) and carcass traits in purebred Angus cattle was evaluated in this study to expand industry knowledge of the impact of carcass trait selection on HP and the potential use of carcass traits as indicators of HP. Historical data consisting of 1,462 records for HP and 4,519 records for carcass traits from the Iowa State University McNay Memorial Research and Demonstration Farm were used in this study. A pedigree consisting of 10,455 individuals with parent generations ranging from 1 to 9 for sires and 1 to 11 for dams was used to build relationships among individuals. Genetic correlations between HP and carcass traits were analyzed using multivariate models consisting of HP, weaning weight (WWT), and a single carcass trait. Results from this study estimated a low heritability of 0.09 ± 0.06 for HP and estimates of 0.36 ± 0.04 for ribeye area (REA), 0.39 ± 0.04 for backfat thickness (FAT), 0.48 ± 0.04 for marbling score (MS) 0.38 ± 0.04 for hot carcass weight (HCW), 0.18 ± 0.03 for weaning weight direct (WWTd), and 0.07 ± 0.02 for weaning weight maternal (WWTm). Genetic correlations between HP and both carcass and weaning traits were negative with estimates of -0.32 ± 0.23 for REA, -0.22 ± 0.23 for FAT, -0.10 ± 0.22 for MS, -0.44 ± 0.21 for HCW, and -0.20 ± 0.25 for WWTd. All estimates of genetic correlation were accompanied by large standard errors. The results from this study suggest a potential antagonistic genetic relationship between heifer pregnancy and carcass trait performance in this herd of Angus cattle.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147864099","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":"Effects of stocking density on growth, physiological, and puberty responses of replacement beef heifers reared in drylots.","authors":"Camila P Prado, Reinaldo F Cooke, Shea J Mackey, Autumn T Pickett, Guilherme A Monteiro, Izadora S De Souza, Courtney L Daigle, Kelsey M Harvey","doi":"10.1093/jas/skag151","DOIUrl":"https://doi.org/10.1093/jas/skag151","url":null,"abstract":"<p><p>This experiment evaluated growth, physiological responses, and puberty attainment in heifers reared in drylots with different stocking densities. A total of 240 heifers (75% Angus × 25% Brahman) were used. Heifers were ranked by age (270 ± 1 d), body weight (BW on d -3; 232 ± 2 kg) and temperament score on d 0, and assigned to drylot pens with: a) 14 m2/heifer (HDENS), b) 28 m2/heifer (MDENS), c) 42 m2/heifer (LDENS), or to pastures with 1,380 m2/heifer (CON). Each pen or pasture (n = 6/treatment) housed 10 heifers. Negligible forage was available for CON, and all treatments received the same limit-fed diet (∼9 kg/heifer daily, dry matter basis). Shrunk BW was recorded on d -3 and 171 to calculate BW gain. Heifers were fitted with an ear tag on d 0 to record behavioral responses. Blood samples were collected weekly for plasma progesterone analysis. Whole blood samples were collected on d 0, 58, 114, and 170 for mRNA isolation. Hair samples from the tail switch were collected on d 0, 30, 58, 85, 114, 142, and 170. Data were analyzed with pen or pasture as experimental unit. No treatment effects were detected (P = 0.92) for BW gain (∼0.647 kg/d). Heifers from CON spent more time eating (P < 0.01) and less time in other activity categories (active, highly active, and non-active; P ≤ 0.05) compared with heifers reared in drylots. Hair cortisol concentrations were greater (P ≤ 0.02) for HDENS compared with CON and MDENS on d 30, greater (P ≤ 0.04) for HDENS compared with all other treatments on d 58 and 142, and less (P ≤ 0.05) for CON compared with all drylot treatments on d 170 (treatment × day; P = 0.08). Expression of heat shock protein (HSP)-70 mRNA was greater (P ≤ 0.02) for HDENS compared with all other treatments on d 170 (treatment × day; P = 0.04). Expression of HSP-72 mRNA was greater (P < 0.01) for LDENS compared with all other treatments on d 114, and greater (P < 0.01) in HDENS compared with all other treatments on d 170 (treatment × day; P < 0.01). A greater (P ≤ 0.05) proportion of CON were pubertal by week 22 of the experiment compared with all other treatments, and compared with MDENS and HDENS on week 23 (treatment × day; P < 0.01). In summary, rearing heifers in drylots with high stocking density (14 m2/heifer) increased chronic stress and delayed puberty compared with pasture heifers, whereas reducing drylot stocking density (28 or 42 m2/heifer) attenuated stress responses but did not benefit heifer reproductive development.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147864082","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":"Effects of dietary starch concentration and feeding management regimen on bacterial pathogens in liver abscesses and ruminal and colonic epithelial tissues in feedlot steers.","authors":"Kasi N Schneid, Mina Abbasi, J Daniel Young, Alyssa K Deters, Xiaorong Shi, Leigh Ann George, T G Nagaraja, Ty E Lawrence, John T Richeson, Kendall L Samuelson","doi":"10.1093/jas/skag131","DOIUrl":"https://doi.org/10.1093/jas/skag131","url":null,"abstract":"<p><p>This study evaluated the main and interactive effects of dietary starch concentration (49.1% [control] or 64.4% [high starch]) and feeding management regimen (regular [REG] or erratic [ERR]) on prevalence of Fusobacterium necrophorum subsp. necrophorum, F. necrophorum subsp. funduliforme, Trueperella pyogenes and Salmonella enterica in liver abscesses (LA) and ruminal and colonic tissues of finishing beef steers. Intact LA (n = 132) and sections of ruminal (n = 131) and colonic (n = 120) epithelial tissues were collected from steers at slaughter. Samples were cultured, before and after enrichment, to determine prevalence of four bacterial pathogens and quantitative PCR (qPCR) was used to determine prevalence and concentrations of the two subspecies of F. necrophorum. Subsp. necrophorum was the dominant pathogen in LA, whereas subsp. funduliforme was dominant in ruminal and colonic tissues by both culture and qPCR methods. Steers fed the high starch diet had greater prevalence (P =  0.01) of subsp. necrophorum, T. pyogenes, and S. enterica in LA compared to steers fed the control diet, indicating the potential impact of dietary starch on promoting bacterial translocation. Of the 132 LA analyzed, culture and qPCR identified 21.7% and 16.4% of LA, respectively, to have subsp. funduliforme, without the subsp. necrophorum, suggesting that subsp. funduliforme without subsp. necrophorum may have caused LA. Concentrations of F. necrophorum in LA were between 7.0 to 7.5 log10 CFU per g and were 2 to 3 log less in ruminal and colonic epithelial tissues and were not affected by the diet (P ≥ 0.08). The prevalence of S. enterica was greater (P <  0.01) in colonic (71.9%) than ruminal epithelial tissues (48.3%), suggesting that the colon may be the major source of the Salmonella in LA. A total of 8 serotypes were identified, and the majority (88.6%) belonged to Kentucky (27.2%), Montevideo (26.2%), Anatum (23.3%), and Lubbock (11.9%). Feeding management regimen had minimal effect, however, diet affected prevalence of the pathogens in LA but not ruminal and colonic epithelial tissues. The prevalence and concentrations of both subspecies of F. necrophorum in colonic epithelial tissue suggest the possibility of the colon being a source of LA pathogens. However, the prevalence and concentration of F. necrophorum in colonic epithelial tissues were much less than that of ruminal tissues, suggesting that the rumen may be the primary reservoir of F. necrophorum in LA.</p>","PeriodicalId":14895,"journal":{"name":"Journal of animal science","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147864101","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}