Scholarly Works, School of Animal Sciences

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    Lawsonia intracellularis infection induces changes in microbial community function and composition associated with reduced pig growth and feed efficiency
    Helm, Emma T.; Burrough, Eric R.; Gabler, Nicholas K.; Leite, Fernando L. (2026-01-05)
    Background: Lawsonia intracellularis and its resulting disease remains a troubling pathogen for pork producers worldwide. In the current experiment, we aimed to characterize the microbiome of pigs challenged with L. intracellularis through peak disease impact to better understand microbial community function and how microbial changes may contribute to disease and resulting decreased growth. Twenty-four L. intracellularis negative barrows were assigned to either L. intracellularis negative (NC) or L. intracellularis challenged (PC) treatment groups (n = 12 pigs/treatment). On days post-inoculation (dpi) 0, PC pigs were inoculated with L. intracellularis. Feed disappearance was monitored daily, body weights and fecal samples were collected weekly. At dpi 21, pigs were euthanized for sample collection and macroscopic lesion scoring. Results: Pigs challenged with L. intracellularis had sustained reductions in growth performance and feed intake throughout the 21-day period (P < 0.001). This was accompanied by changes to fecal microbial communities, particularly increased abundance of Chlamydia suis in challenged pigs at dpi 7, 14, and 21. Changes to microbial communities were also accompanied by differences in microbial metabolism, marked most notably by signatures of lesser amino acid biosynthesis and greater nucleotide synthesis in challenged pigs. Conclusions: In summary, L. intracellularis challenge produced reductions in growth and feed intake. This was accompanied by sustained changes to fecal microbial communities, particularly sustained increased abundance of C. suis in challenged pigs. Changes to microbial communities were also accompanied by differences in microbial metabolism which likely play a role disease.
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    Single-cell transcriptomic analysis suggests potential differences in the developmental stage and quantity of adipose progenitor cells between bovine intramuscular and subcutaneous fat
    Tan, Zhendong; Lyu, Pengcheng; Jiang, Honglin (2025-11-27)
    Background: Intramuscular fat (IMF), the white adipose tissue deposited between skeletal muscle fibers, is a key determinant of beef quality due to its contribution to meat flavor, juiciness, and tenderness. However, IMF develops later and grows more slowly, compared to other fat depots such as subcutaneous fat (SF) in cattle. The cellular and molecular mechanisms underlying the delayed development and slow growth of IMF remain poorly understood. We hypothesized that later development and slower growth of IMF compared to SF may, in part, arise from the differences in their progenitor cells. Results: We performed single-cell RNA sequencing (scRNA-seq) on the stromal vascular fractions (SVFs) from IMF and SF of adult Angus crossbred steers as well as the mononuclear cell fractions (MCFs) from skeletal muscles of newborn Angus crossbred bull calves, with each tissue type collected from two animals. A total of 14,802 cells from 6 animals were sequenced. Clustering analysis revealed that these cells comprised ten cell types, including adipose progenitor cells (APCs), muscle satellite cells (MuSCs), myoblasts, smooth muscle cells, and various immune cell populations. The SF-derived SVF from adult cattle harbored a significantly higher proportion of APCs than the IMF-derived SVF. The MCFs from newborn calves did not contain detectable APCs. Subclustering analysis revealed that the APCs comprised six subpopulations (C0–C5), among which C3 and C5 were absent in the IMF-derived SVF while C1 was markedly less abundant in the IMF-derived SVF than in the SF-derived SVF. Gene set variation analysis and pseudotime trajectory analysis showed that C1 and C3 represented more differentiated APCs, with higher expression of genes involved in adipogenesis, such as PPARG, ADAM12, and PPARGC1A, whereas subclusters C0 and C4 represented undifferentiated, uncommitted APCs, with higher expression of genes involved in DNA replication and cell adhesion, compared to the other subclusters. Conclusions Overall, this single-cell transcriptomics study suggests two potential differences in APCs between IMF and SF in adult cattle: (1) IMF contains fewer APCs than SF; (2) APCs in IMF are adipogenically less committed and less differentiated compared to APCs in SF. These differences may partially explain why IMF develops later and grows more slowly than SF in cattle. This study also suggests that, in cattle, intramuscular fat begins to develop postnatally, challenging the widely held belief that it forms during late gestation.
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    Prepartal liver glutathione and its association with lactation performance, metabolism, and health outcomes in transition dairy cows
    Souza Lima, Ana; de Oliveira, Maria; Begalli, Gustavo; Grazziotin, Rodrigo; Halfen, Jessica; Trevisi, Erminio; Osorio, Johan S. (2025-09-18)
    Our objective was to determine the association of prepartal liver glutathione (GSH) concentration with lactation performance parameters, metabolism and inflammation, and gene expression in transition dairy cows. Sixty Holstein dairy cows were enrolled at −21 ± 3.3 d relative to calving and remained on trial until 30 DIM. All cows received the same close-up diet from −21 DIM until calving (1.67 Mcal/DM and 13.5% CP) and lactation diet from calving until 30 DIM (1.80 Mcal/DM and 17.7% CP). A liver biopsy was performed in all cows at −8 d (±3.2 d) relative to calving, and total GSH was measured using a commercial colorimetric kit. This metric was used to retrospectively classify cows by GSH as high (HGSH; n = 15), medium-high (MHGSH; n = 15), medium-low (MLGSH; n = 15), and low (LGSH; n = 15). Liver samples were collected at −8, 7, and 21 DIM, and blood samples at −21, −10, 2, 7, 14, and 21 DIM to evaluate oxidative stress, metabolism, inflammation, and liver function biomarkers. Statistical analysis was performed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) with the preplanned contrast to test a linear effect with increasing levels of GSH. A linear increase in prepartal energy balance (EB; from −1.55 to 1.11 Mcal/d) and postpartal BCS (from 3.00 to 3.16) was observed as prepartal liver GSH increased from LGSH to HGSH groups, suggesting an association between prepartal liver GSH and energy metabolism around parturition. This effect was also associated with a trend for a linear increase in prepartal DMI as prepartal liver GSH increased across groups. We observed a linear increase in ECM (from 50.2 to 54.7 kg/d) and milk protein yield (from 1.33 to 1.46 kg/d) as prepartal liver GSH levels increased. Neither reactive oxygen metabolites nor antioxidant capacity measured via ferric reducing antioxidant power were altered according to prepartal liver GSH. However, there was a linear increase in the total thiol groups of plasma as prepartal liver GSH increased, suggesting some level of antioxidant protection. A linear increase in total (from 0.83 to 1.74 nmol/mg), reduced (from 0.66 to 1.37 nmol/mg), and oxidized forms of GSH (from 0.07 to 0.17 nmol/mg) was observed in the liver as prepartal liver GSH levels increased. The hepatic activity of gamma-glutamyl-transferase at −8 DIM was greater in MHGSH cows compared with LGSH and HGSH. At −8 DIM, a linear upregulation of genes related to GSH metabolism, including GCLC, GGCT, and GSR, was observed as prepartal liver GSH increased, suggesting that transcriptional regulation may contribute to the GSH phenotype observed in this study. These results emphasize the importance of maintaining adequate hepatic GSH reserves before calving to support metabolic adaptation and lactation performance. Future research should explore the direct effect of GSH on lactation performance and oxidative stress protection, as well as nutritional and management factors to enhance hepatic GSH synthesis before calving.
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    Long-term impacts of 48-h water and feed deprivation on blood and performance responses of grazing Bos indicus Nellore heifers
    Abreu, Mateus J. I.; Marques, Rodrigo S.; Cidrini, Iorrano A.; Batista, Luis H. C.; Ferreira, Igor M.; Oliveira, Karla A.; Cruz, Vinicius A.; Limede, Arnaldo C.; Sousa, Luciana M.; Franca, Matheus Q. S.; Bisio, Gustavo H. M.; Siqueira, Gustavo R.; Resende, Flavio D. (Oxford University Press, 2024-02)
    The study investigated the effects of 48-h water and feed deprivation on blood and the performance of grazing Nellore (Bos indicus) heifers. Twenty-four Nellore heifers (initial body weight [BW] = 238 ± 10 kg; age = 16 ± 2 mo), were ranked by initial BW and age and randomly assigned to one of the two treatments: (1) grazing animals with free access to pasture, water, and mineral-mix (CON; n = 12), or (2) the same grazing conditions but deprived of pasture, water, and mineral-mix for 48 h (DPR; n = 12). The paddocks consisted of Urochloa brizantha cv. Marandu, using a continuous and fixed stocking rate. The experiment lasted 225 d, with the first 14 d considered as the adaptation period (days −14 to −1) and the subsequent 211 d as the evaluation period (days 0 to 211). From days 0 to 2, treatments were applied by keeping the DPR heifers in pens and reintegrating them into the experimental area after a 48-h water and feed deprivation. Individual full BW was recorded on days −14, −13, −1, before (day 0) and after (day 2) treatment application, and on days 6, 11, 12, 41, 42, 210, and 211. Blood samples were collected in the morning on days 0, 2, 6, 12, and 211. A treatment effect was detected (P < 0.001) for shrink BW from days 0 to 2, which was greater (P < 0.001) in DPR vs. CON heifers. Subsequently, DPR animals were lighter (P < 0.001) compared with CON heifers by the end of the deprivation period (day 2). From days 4 to 211, DPR was lighter (P < 0.001) compared with CON heifers after treatment application and for the entire experimental period. In the first 10 d after treatment application (days 2 to 12), DPR heifers showed a partial compensatory average daily gain (ADG; P < 0.001) compared with CON heifers, while no significant differences were observed in ADG between the treatments from days 12 to 42 and 42 to 211 (P > 0.420). Overall ADG (days 2 to 211) was greater (P < 0.001) for DPR vs. CON heifers. All serum variables, except AST, were higher (P < 0.001) in DPR than in CON heifers on day 2 after treatment application. Our study demonstrates that grazing Nellore heifers subjected to 48-h water and feed deprivation experienced significant alterations in their blood metabolites and BW immediately after the stressful event. Although the deprived heifers partially compensated for their BW loss in the early days post-deprivation, they remained 12 kg lighter than the non-deprived animals throughout the production cycle. Routine management practices in beef cattle operations, such as shipping and receiving at feedlot facilities, may cause the animals to go without food and water for extended periods. The findings of this study reveal that Nellore (Bos indicus) heifers subjected to a 48-h water and feed deprivation exhibited substantial changes in their blood metabolites and lost 14.6% of their body weight by the completion of the deprivation period. Although the deprived heifers showed a partial compensatory increase later, they remained 12 kg lighter than the non-deprived heifers throughout the production cycle.
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    Effect of forage quality and narasin inclusion on ruminal fermentation, nutrient intake, and total tract digestibility of Nellore steers
    de Paula, Matheus Felipe Freitas Viana; Marques, Rodrigo S.; Pires, Alexandre Vaz; Soares, Leticia Carolina Bortolanza; Limede, Arnaldo Cintra; Ferreira, Evandro Maia; Polizel, Daniel Montanher (Oxford University Press, 2024-08-02)
    The study aimed to evaluate the effects of forage quality and narasin inclusion on intake, digestibility, and ruminal fermentation of Nellore steers. Twenty-eight rumen-cannulated Nellore steers (initial body weight [BW] = 350 ± 32.4 kg) were allocated to individual pens in a randomized complete block design, with 7 blocks, defined according to the fasting BW at the beginning of the experiment. The steers were randomly assigned within blocks to 1 of 4 experimental diets in 2 × 2 factorial arrangements, being the first-factor forage quality (MEDIUM = 81 g of CP/kg of dry matter [DM], and HIGH = 153 g of CP/kg of DM), and the second factor was the inclusion (N13 = diet plus 13 mg/kg of DM of narasin) or not (N0) of narasin (Zimprova; Elanco Animal Health, São Paulo, Brazil). The experiment consisted of a 28-d period with 22 d for adaptation and the last 6 d for data collection. No haylage quality × narasin interaction (P ≥ 0.68) was observed on DM and nutrient intake. Haylage quality affected (P ≤ 0.01) DM intake, with greater values observed for steers fed HIGH compared with MEDIUM haylage. There was an increase (P < 0.001) in OM, NDF, hemicellulose, and CP intake for steers consuming HIGH vs. MEDIUM haylage. Including N13 did not affect (P > 0.39) DM and nutrient intake of steers. No haylage quality × narasin interactions were detected (P ≥ 0.60) for total tract nutrient digestibility. However, steers fed with HIGH haylage showed an increase (P > 0.001) in DM and digestibility of all nutrients compared with MEDIUM. Steers fed a MEDIUM haylage had a greater (P < 0.01) proportion of acetate compared with steers fed HIGH during all evaluated hours. Steers fed HIGH haylage had a greater (P < 0.01) proportion of propionate at 0 h compared with steers consuming MEDIUM, whereas at 12 h, steers consuming MEDIUM hay had a greater (P < 0.01) proportion of propionate vs. HIGH haylage. A haylage quality × narasin and haylage quality × time of collection interactions were detected (P ≤ 0.03) for rumen ammonia concentration, which was reduced (P < 0.03) in N13 vs. N0 steers consuming HIGH haylage. Collectively, high-quality haylage allows increased consumption and digestibility, with more energy-efficient ruminal fermentation. In addition, narasin might be an important nutritional tool in forage-based diets to enhance the ruminal fermentation parameters of Bos indicus Nellore steers.
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    Using audio-visual monitoring to evaluate immune and behavioral indicators to lipopolysaccharide challenge in beef cattle
    Limede, Arnaldo C.; Marques, Rodrigo S.; Cidrini, Fernando A. A.; Souza, Gilyard A. P.; Santos, Erollykens F.; Wu, Xiaohui; De Souza, Izadora S.; Qualharello, Tamara; Cooke, Reinaldo F.; Chen, C. P. James (Oxford University Press, 2025-10)
    This experiment investigated the integration of camera and microphone monitoring with AI technologies to assess immune responses, activity patterns, and respiratory acoustic changes in beef cattle using lipopolysaccharide (LPS) administration as a model. Twelve Angus steers [age = 15 ± 1 mo; body weight (BW) = 399 ± 6 kg] were housed in four feedlot pens (3 steers/pen). On day 0, steers were ranked by initial BW, and assigned to one of two groups in a crossover design, with treatments initiated at hour 0: 1) an intravenous bolus dose of bacterial LPS (0.5 μg/kg of BW; n = 12), or 2) 5 mL intravenous injection of 0.9% sterile saline (CON; n = 12). The experimental period lasted 9 days (days -3 to 6) with 20 days of washout between periods. Video footage was recorded, and animal positions were tracked using a deep learning-based object detection algorithm (YOLOv11). Video frames were used to generate activity heatmaps for three consecutive one-hour intervals: h 0-1, 1-2, and 2-3. Microphones mounted on each animal's halter were used to measure differences in breathing patterns. Steers rectal temperature was assessed, and blood samples were collected at hours 0, 4, 8, 24, 48, 72, and 96 relative to treatment administration. LPS induced a neuroendocrine response by increasing plasma cortisol concentrations (P ≤ 0.04) at 4, 8, and 12 h, non-esterified fatty acid (NEFA) at 8, 12, and 24 h, while reducing (P < 0.01) circulating beta-hydroxybutyrate (BHBA) at 4 and 8 hours vs. CON group. LPS steers displayed an increase (P < 0.01) in rectal temperature at 4 and 12 h, and a reduction (P < 0.01) in intake at 24, 48, and 72 h post-challenge vs. CON cohorts. The YOLOv11 identified reduced pen exploration and increased clustering behavior among LPS steers 1.5 h post-challenge. Spatial analysis of steer movement further confirmed that LPS steers exhibited increased resting behavior and avoided the feeding bunk throughout the 3-hour window. In parallel, Mel spectrogram analysis of breathing sounds 2 hours after LPS revealed an altered respiratory pattern in LPS steers, characterized by short, sharp, and high-pitched sounds suggestive of labored breathing. Collectively, LPS administration elicited behavioral and physiological changes, which were detected using integrated AI-driven video and audio monitoring systems. These findings suggest that these technologies may offer a promising approach for real-time assessment of cattle behavior and respiratory dynamics in cattle.
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    Ruminant nutrition symposium: novel microbial solutions to optimize production efficiency in beef and dairy systems
    Cappellozza, Bruno I.; Cooke, Reinaldo F.; Amaral, Rafael C.; Bach, Alex; Engle, Terry E.; Ferraretto, Luiz F.; Marques, Rodrigo S.; Miller, Alexandra C.; Moriel, Philipe; Vendramini, Joao M. B. (Oxford University Press, 2025-05)
    The livestock industry is in search of sustainable technologies that enhance the profitability and sustainability of food animal production. Among these technologies, microbial solutions include living bacteria that may support soil, plant, and animal health. Bacterial inoculants have been the most used additives to modulate whole-plant corn silage fermentation, including homo- and heterofermentative bacteria. Bacterial inoculants can improve fermentation characteristics of grass silage, whereas the wide variation in chemical composition and management practices across cool- and warm-season grasses makes the outcome of inoculation less predictable. Tailored recommendations for bacterial inoculant species and strains, based on species and management practices, are necessary to increase the predictability of silage inoculation, including whole-plant corn and grass silage. Microbial solutions are also used as feed additives for beef and dairy cattle, including Bacillus-based direct-fed microbials (DFM). Recent advancements in Bacillus-based DFM supplementation have shown promise for enhancing cow-calf productivity through improved gut health, immune function, and nutrient metabolism. Incorporating Bacillus-based DFM into stocker and feedlot receiving programs can improve feed intake and digestibility, health, and productivity of high-risk cattle. Bacillus-based DFM have also been used in feedlot diets to address public concerns with antimicrobial resistance but also to improve cattle performance and reduce the incidence of diseases. Multispecies bacterial-based DFM are promising alternatives to counteract the potentially adverse effects of Salmonella, as these DFM supported the integrity of the intestinal epithelial cells under in vitro settings. In dairy cattle, most DFM-related research in mature cows has targeted improvements in rumen fermentation and enterocyte health. In general, improvements in milk production due to supplementation of bacteria-based DFM seem to be more consistent than those obtained with yeast-based DFM. Collectively, microbial solutions have the potential to optimize silage quality, enhance feed intake and digestibility by ruminants, and support cattle health and performance while fostering sustainable practices in beef and dairy production systems.
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    Moringa Extract to Modulate Rumen Fermentation and Lactation Performance of Ewes
    Chagas, Renata Alves; Fernandes, Tatiane; Barbosa, Cristiane Rebouças; de Carvalho Pantoja, Jessica; Navarro, Samuel Rodrigues; Morais de Oliveira, Marcus Vinicius; Cardoso, Cláudia Andréa Lima; de Vargas, Fernando Miranda (MDPI, 2025-11-25)
    This study aimed to evaluate the supplementation of aqueous extract of Moringa oleifera (AEMO) as a natural ruminal modulator to improve the lactation performance of ewes. The AEMO was prepared by chopping Moringa oleifera leaves and diluting them in distilled water (163.3 g DM/L). Twelve ewes were used in a replicated 3 × 3 Latin square, with periods of 14 days (assessments on the last five days of each period). Treatments were as follows: 20 mL of water as Control, 20 mL of AEMO (20-AEMO), and 40 mL of AEMO (40-AEMO). Ewes were milked twice a day (7:30 a.m. and 2:30 p.m.). Diet corresponds to grain mix (at 3% of BW) and hay ad libitum. We determined the intake, digestibility, fermentative measurements, metabolic measurements, and milk production and composition. Intake and digestibility were not affected by AEMO. Milk yield and the concentrations of fat, protein, and lactose were numerically lower in ewes supplemented with 20-AEMO. A linear decrease in milk protein yield was observed when the highest extract level (40-AEMO) was used. Ruminal pH did not differ among treatments; however, there was a tendency for reduced acetate and increased propionate concentrations, which corresponded with a non-significant numerical decrease in methane estimates in 40-AEMO group. Blood and urinary parameters were not affected by AEMO supplementation. Inclusion of Moringa extracts as an additive in lactating ewes diet does not affect intake and nutrient digestibility, but tends to affect ruminal fermentation and microbial synthesis, with possible changes in methane emission estimation, and impair milk protein production. Therefore, we recommend studies with different extract concentrations to investigate possible effects on rumen fermentation and the synthesis of milk compounds.
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    Evaluation of F18 enterotoxigenic Escherichia coli intestinal attachment and early disease onset in nursery pigs
    Due, Elizabeth M.; Miller, Kayla A.; Burrough, Eric R.; Helm, Emma T.; Gabler, Nicholas K. (Frontiers, 2025-12)
    Introduction: Enterotoxigenic Escherichia coli (ETEC) is a major cause of post-weaning diarrhea and reduced performance in nursery pigs. While ETEC pathogenesis is well established, the early epithelial and functional responses to F18 ETEC infection remain poorly defined. This study investigated the effects of F18 ETEC on bacterial attachment, intestinal function, and early epithelial cell responses. Methods: Ten days post-weaning, 24 individually housed pigs (n = 6/treatment) were orally inoculated with 5 ml of F18 ETEC at 107, 108, or 109 colony-forming units (cfu)/ml, or with a negative control (NC). Over a 5-day post-inoculation period, fecal scores, body weight, and growth performance were recorded. Thereafter, pigs were humanely euthanized, ileal contents and fecal F18 and LT gene abundances were quantified, and ileal tissue was assessed ex vivo for transepithelial resistance (TER), FITC-dextran permeability (FD4), and active glucose and glutamine transport. Jejunum, ileum, and colon were examined for histomorphology, F18 attachment (in situ hybridization), chloride secretion (cystic fibrosis transmembrane conductance regulator [CFTR] protein), and proliferation (Ki67). Ileal gene expression of epithelial proliferation, maturation, and differentiation markers was analyzed. Results: ETEC-challenged pigs had higher fecal scores than NC (p = 0.01), without differences in average daily feed intake or gain:feed (p > 0.10). Average daily gain tended to be lower in the 108 ETEC group compared to the NC (p = 0.07). In ETEC pigs, F18 and LT gene abundances were elevated (p < 0.001) and F18 attachment increased across all intestinal segments (p < 0.10), being greatest in the ileum (p < 0.001). CFTR protein abundance increased in all regions with ETEC challenge (p < 0.05), and Ki67 abundance tended to be lowest in the 109 group (p = 0.08). Notch expression tended to increase (p = 0.08) and Hes1 tended to decrease (p = 0.08) with ETEC challenge, suggesting altered epithelial renewal dynamics. Nutrient transport, TER, and FD4 flux were unaffected (p > 0.10). Discussion/Conclusion: A 5-day F18 ETEC challenge induced ETEC attachment and diarrhea. These findings support a model where F18 ETEC epithelial attachment drives diarrhea through an enterotoxin-mediated, CFTR-dependent secretory mechanism rather than structural epithelial damage.
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    Does fall manure injection cause differential growth and forage nutritive value in small grains?
    Hilfiker, Derek R.; Maguire, Rory O.; Ferreira, Gonzalo; Thomason, Wade E.; Stewart, Ryan D. (Wiley, 2024-05-01)
    Producers utilizing fall manure injection have reported increased growth and greenness in small grains growing on the injection band compared to small grains growing between injection bands. To determine how producers utilizing fall manure injection in small grains should manage potential differential growth, 24 sites under fall manure injection were established. Soil samples were taken in-band and between-band 1 month after manure application and at silage harvest for soil NO3-N. Small grain growth stage was assessed 1 month after planting and at silage harvest, while dry matter (DM) yield and forage nutritive value parameters were assessed at silage harvest. Soil NO3-N was elevated in-band compared to between-band 1 month after manure application (p < 0.05); however, this did not persist until silage harvest. No differences in growth stage were observed 1 month after planting in 2021; however, growth stage means were consistently elevated in-band in 2022, likely due to earlier planting dates in 2022 compared to 2021. Growth stage at harvest was the same in-band and between-band at each site. Small grain DM yield was only increased in-band compared to between-band in three of 24 sites. Two of the three sites planted with wheat (Triticum aestivum L.) showed significantly increased DM yield in-band, suggesting DM yield response could be species dependent. No consistent differences in forage nutritive value parameters were observed. As no consistent differences in small grain DM yield and forage nutritive value were found at harvest, we recommend no changes to management practices for producers utilizing fall manure injection in small grains.
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    Fast growth rate is associated with musculoskeletal biomechanical imbalance and dorsal cranial myopathy in broiler chickens
    Lourenço-Silva, Marconi Italo; Norton, Anderson H. III; Jacobs, Leonie (Public Library of Science, 2025-09-01)
    Dorsal cranial myopathy is a degenerative lesion that affects the anterior Latissimus dorsi muscle in broiler chickens, with an etiology that remains unknown. The objective was to investigate the influence of musculoskeletal biomechanical balance and gait on the prevalence of dorsal cranial myopathy in three broiler chicken strains with differing growth potential. Three-hundred and ninety-six broiler chickens from three genetic strains with differing growth potential (fast, intermediate, and slow, 132 birds/ strain) were housed in 18 pens with 22 birds/pen. Five birds/pen (n = 30 birds/genetic strain) were randomly wing- or leg-banded to assess gait and musculoskeletal biomechanical balance (by calculating body angulation) at 1, 2, 3, and 3.7 kg weight sampling points. Dorsal cranial myopathy was assessed one day after birds reached final body weight. Gait and musculoskeletal balance were both negatively impacted by body weight in fast- and slow-growing strains but not in the intermediate-growing strain. Dorsal cranial myopathy was more prevalent in fast-growing broilers compared to other strains, with no case observed in the slow-growing strain. Impaired gait negatively affected musculoskeletal biomechanical balance and increased the prevalence of dorsal cranial myopathy. Our results suggest that genetic strain, musculoskeletal biomechanical imbalance, poor gait, and high body weight are all associated with the prevalence of dorsal cranial myopathy in broiler chickens. We successfully simplified a non-invasive body posture methodology to quantify the musculoskeletal biomechanical balance in broiler chickens.
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    Telomere length as a biomarker for cumulative experience in broiler chickens
    Campbell, Andrew M.; Anderson, Mallory G.; Haussmann, Mark F.; Rowell, Raquel; Jacobs, Leonie (Public Library of Science, 2025-06-25)
    Cumulative experience can be defined as the sum of all positive and negative experiences during an animal’s lifetime. Telomere length shows promise as a biomarker of cumulative experience in humans and non-human animals but is not yet assessed for broiler chickens. Therefore, our objective was to determine telomere length changes due to positive and negative experiences in fast-growing broiler chickens. In three replicated experiments, male Ross 708 broilers were housed in a 2×2 factorial study investigating high environmental complexity as a positive environment (vs. low complexity; 6 pens/treatment) and high stocking density as a negative environment (vs. low density; 6 pens/treatment). Telomere length was quantified at day 48 of age via quantitative RT-PCR (qRT-PCR) from gonad and kidney samples (N=9 samples/ treatment/tissue/experiment). Prior to analysis, raw relative telomere length (rTL) values were z-transformed to allow comparison between experiments. Combined data from the three experiments were analyzed using mixed models with complexity, density, and their interactions as fixed factor and pen nested within experiment and qRT-PCR plate number as random factors. Over all three trials, birds housed in high complexity environments tended (P=0.0503) to have longer telomeres from kidney tissue than birds housed in low complexity environments. Stocking density did not impact combined kidney telomere length and gonadal telomere length was not impacted by environmental complexity or stocking density. Longer telomeres (statistical trend) in response to positive experience (environmental complexity) when compared to low-complexity indicate that high-complexity environments elicited positive cumulative experience in broiler chickens, although effect size was small. Telomere length has the potential to be a valuable tool in the assessment of cumulative experience in production settings, and future works should replicate these findings and expand upon this work by comparing telomere length with other more traditional animal welfare markers.
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    Reductions in protein degradation in the retrosplenial cortex regulate contextual fear memory formation in a sex-independent manner
    Turner, Meagan; Ball, Olivia; Ray, W. Keith; Helm, Richard F.; Jarome, Timothy J. (Elsevier, 2025-12-16)
    The retrosplenial cortex (RSC), which serves as a hub to connect the hippocampus and amygdala with other cortical regions, has been shown to play a role in the formation of contextual fear memories. However, the molecular mechanisms by which the RSC forms memories and whether sex differences exist within these mechanisms remain largely unknown. Increases in ubiquitin–proteasome-mediated protein degradation have been shown to be sex-dependently involved in the formation of contextual fear memories in multiple brain regions, including the hippocampus and amygdala. To date, whether increases in protein degradation are needed in the RSC for memory formation in either sex has yet to be examined. Here, we found that proteasome function in the RSC decreases after contextual fear conditioning in both male and female rats. Consistent with this, increasing proteasome activity in the RSC via CRISPR-dCas9-mediated upregulation of Psmd14 impaired contextual fear memory in a mixed sex cohort. Interestingly, proteomic analysis of degradation-specific lysine-48 (K48) polyubiquitination in the RSC of fear-conditioned rats showed largely distinct protein degradation targets and impacted pathways across the sexes. This suggests that despite the shared need for reductions in protein degradation, males and females are using this mechanism in different ways to form the same memory. Together, these data demonstrate that reductions in protein degradation in the RSC are critical for contextual fear memory formation in both males and females and indicate that the molecular changes in the RSC during memory formation may be distinct from those of other more commonly studied brain regions.
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    Branched-chain amino acids in muscle growth: mechanisms, physiological functions, and applications
    Xu, Shuyong; Zhao, Guangyong; Hanigan, Mark D.; Cantalapiedra-Hijar, Gonzalo; Li, Mengmeng (2025-12-03)
    Skeletal muscle accounts for approximately 40% of body mass and 50%–75% of whole-body protein, playing a central role in meat production and quality. Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile. Branched-chain amino acids (BCAA), including leucine (Leu), isoleucine (Ile), and valine (Val), are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production. Additionally, BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades, which significantly influence physiological processes, such as protein synthesis and degradation, glucose and lipid metabolism, and cell apoptosis and autophagy. These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways. This review summarizes BCAA transporters and catabolic metabolism, their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium, and applications in animal production. These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations. Graphical Abstract
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    Single-Cell Cloning and Transcriptomic Analysis Support a Myogenic Origin of Bovine Intramuscular Adipocytes
    Tan, Zhendong; Pokhrel, Binod; Jiang, Honglin (MDPI, 2025-11-18)
    Intramuscular fat (IMF) refers to the adipose tissue located between muscle fibers and is a major determinant of meat quality in cattle. The cellular origin of bovine intramuscular adipocytes remains unclear. Therefore, the objective of this study was to investigate this origin. We derived single-preadipocyte clones from IMF and subcutaneous fat (SF) of cattle through single-cell cloning and subsequent validation of their potential to differentiate into adipocytes. Transcriptomic analysis of selected single-preadipocyte clones revealed that although both IMF- and SF-derived preadipocyte clones expressed classical preadipocyte markers such as PDGFRA, DLK1, and ZNF423, they differed significantly in global gene expression profile. Notably, many muscle-specific genes (e.g., MYOG, MB, and MYH3) were expressed at high levels in IMF-derived preadipocyte clones while not expressed in SF-derived clones. Functional enrichment analysis of differentially expressed genes between IMF- and SF-derived preadipocyte clones indicated that many muscle-related functions were enriched in the former. Furthermore, high-level expression of muscle-specific genes persisted in mature adipocytes differentiated from IMF-derived preadipocyte clones. We also found that bovine satellite cells, the widely considered progenitor cells of myocytes in postnatal animals, had the ability to form both myocytes and adipocytes under respective differentiation conditions. Based on these findings, we conclude that in cattle, at least some intramuscular adipocytes are derived from satellite cells.
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    Heat stress alters hematological parameters in barrows and gilts
    Rudolph, Tori E.; Roths, Melissa; Freestone, Alyssa D.; White-Springer, Sarah H.; Rhoads, Robert P.; Baumgard, Lance H.; Selsby, Joshua T. (Oxford University Press, 2024-01-03)
    The purpose of this investigation was to establish the role biological sex plays in circulating factors following heat stress (HS). Barrows and gilts (36.8 +/- 3.7 kg body weight) were kept in either thermoneutral (TN; 20.8 +/- 1.6 degrees C; 62.0% +/- 4.7% relative humidity; n = 8/sex) conditions or exposed to HS (39.4 +/- 0.6 degrees C; 33.7% +/- 6.3% relative humidity) for either 1 (HS1; n = 8/sex) or 7 (HS7; n = 8/sex) d. Circulating glucose decreased as a main effect of the environment (P = 0.03). Circulating non-esterified fatty acid (NEFA) had an environment x sex interaction (P < 0.01) as HS1 barrows had increased NEFA compared to HS1 gilts (P = 0.01) and NEFA from HS7 gilts increased compared to HS1 gilts (P = 0.02) and HS7 barrows (P = 0.04). Cortisol, insulin, glucagon, T3, and T4 were reduced as a main effect of environment (P <= 0.01). Creatinine was increased in HS1 and HS7 animals compared to TN (P <= 0.01), indicative of decreased glomerular filtration rate. White blood cell populations exhibited differential patterns based on sex and time. Neutrophils and lymphocytes had an environment x sex interaction (P <= 0.05) as circulating neutrophils were increased in HS1 barrows compared to TN and HS7 barrows, and HS1 gilts (P <= 0.01) and HS7 barrows had less neutrophils compared to TN barrows (P = 0.01), whereas they remained similar in gilts. In contrast, barrow lymphocyte numbers were similar between groups, but in HS7 gilts they were decreased compared to TN and HS1 gilts (P <= 0.04). In total, these data demonstrate that HS alters a host of circulating factors and that biological sex mediates, at least in part, the physiological response to HS.
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    Peripartal supplementation of a blend of postbiotics and essential oil compounds influences ruminal fermentation while improving feed intake and milk production in transition dairy cows [Supplemental material]
    Begalli, Gustavo; Maldonado, Laura; de Oliveira, Victor Augusto; Souza Lima, Ana Flavia; Minuti, Andrea; Trevisi, Erminio; Halfen, Jessica; Fernandes, Tatiane; Yoon, Ilkyu; Osorio, Johan (2025-11)
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    Multiple administrations of bovine-appeasing substance during a 42-d preconditioning program followed by feedlot receiving and its effects on physiologic, health, and performance responses of feeder cattle
    Kvamme, Keenan; Marques, Rodrigo S.; Cruz, Vinicius Alves; Cintra, Arnaldo Limede; Ogg, Makayla Anne; McCoski, Sarah R.; Posbergh, Christian J.; Bradbery, Amanda N.; Mercadante, Vitor R. G.; Mackey, Shea J.; Pickett, Autumn T.; Cooke, Reinaldo F. (Oxford University Press, 2024-06-19)
    This experiment evaluated the effects of multiple bovine-appeasing substance (BAS) administration during a 42-d preconditioning program followed by a feedlot receiving period on productivity, health, and physiological variables of feeder cattle. Ninety calves were weaned, weighed, loaded into a livestock trailer, transported for 70 km, and unloaded at the Bozeman Agricultural Research and Teaching Farm for a 42-d preconditioning program. Upon arrival, calf body weight (BW) was recorded again, and both pre- and post-transport BWs were averaged and used as calf weaning initial BW. Calves were ranked by BW, sex, and age in a completely randomized design and assigned to receive 1) multiple administrations of BAS at weaning (day 0), days 14, 28, and before transport and feedlot entry (day 42; BAS; RSEA Group, Quartier Salignan, France; n = 9 pens/treatment), or 2) placebo (diethylene glycol monoethyl ether; CON; n = 9 pens/treatment). Treatments (5 mL) were applied to the nuchal skin area of each animal during the preconditioning period. Calves within treatment groups were ranked again by initial BW, sex, and age, in a manner that pens have similar initial BW, age, and three steers and two heifers and allocated to 1 of the18 drylot pens. On day 42, calves were combined within the treatment group, loaded into two different single double-deck commercial livestock trailers, and transported for 1,000 km (approximately 16 h). Upon arrival (day 43), calves were unloaded at the same feedyard. Blood samples were collected on days 0, 3, 7, 14, 21, 28, 42, 43, 46, 50, 57, 64, and 90. Average daily gain, final BW, and feed efficiency did not differ (P > 0.52) between BAS and CON calves in the preconditioning and receiving phases. A treatment x day interaction was detected (P < 0.001) for plasma haptoglobin concentrations, which was greater (P < 0.01) in CON on days 3 and 7 vs. BAS calves. During the preconditioning phase, serum NEFA concentration was reduced (P < 0.01) in BAS on day 3 compared with CON calves. A treatment x day interaction was detected (P = 0.001) for exit velocity, which was greater (P < 0.001) for CON vs. BAS calves on days 3, 7, 14, and 21 during the preconditioning phase and on day 46 of the receiving phase. Therefore, Applications of BAS reduced immunological responses and exit velocity associated with stress caused by management practices, but did not improve performance during the preconditioning and receiving phases.
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    Natural variation in LONELY GUY-Like 1 regulates rice grain weight under warmer night conditions
    Sandhu, Jaspreet; Irvin, Larissa; Chandaran, Anil Kumar; Oguro, Shohei; Paul, Puneet; Dhatt, Balpreet; Hussain, Waseem; Cunningham, Shannon S.; Quinones, Cherryl O.; Lorence, Argelia; Adviento-Borbe, Maria Arlene; Staswick, Paul; Morota, Gota; Walia, Harkamal (Oxford University Press, 2024-06-14)
    Global nighttime temperatures are rising at twice the rate of daytime temperatures and pose a challenge for rice (Oryza sativa) production. High nighttime temperature (HNT) stress affects rice yield by reducing grain weight, size, and fertility. Although the genes associated with these yield parameters have been identified and characterized under normal temperatures, the genetic basis of grain weight regulation under HNT stress remains less explored. We examined the natural variation for rice single grain weight (SGW) under HNT stress imposed during grain development. A genome-wide association analysis identified several loci associated with grain weight under HNT stress. A locus, SGW1, specific to HNT conditions resolved to LONELY GUY-Like 1 (LOGL1), which encodes a putative cytokinin-activation enzyme. We demonstrated that LOGL1 contributes to allelic variation at SGW1. Accessions with lower LOGL1 transcript abundance had higher grain weight under HNT. This was supported by the higher grain weight of logl1-mutants relative to the wild type under HNT. Compared to logl1-mutants, LOGL1 over-expressers showed increased sensitivity to HNT. We showed that LOGL1 regulates the thiamin biosynthesis pathway, which is under circadian regulation, which in turn is likely perturbed by HNT stress. These findings provide a genetic source to enhance rice adaptation to warming night temperatures and improve our mechanistic understanding of HNT stress tolerance pathways. Allelic variation in LOGL1 regulates grain weight under high night temperature during reproductive development in rice.
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    Therapeutic effects of mitoquinol during an acute heat stress challenge in growing barrows
    Mayorga, Edith J.; Horst, Erin A.; Goetz, Brady M.; Rodriguez-Jimenez, Sonia; Abeyta, Megan A.; Al-Qaisi, Mohmmad; Rhoads, Robert P.; Selsby, Joshua T.; Baumgard, Lance H. (Oxford University Press, 2024-06-27)
    Study objectives were to determine the effects of mitoquinol (MitoQ, a mitochondrial-targeted antioxidant) on biomarkers of metabolism and inflammation during acute heat stress (HS). Crossbred barrows [n = 32; 59.0 +/- 5.6 kg body weight (BW)] were blocked by BW and randomly assigned to 1 of 4 environmental-therapeutic treatments: 1) thermoneutral (TN) control (n = 8; TNCon), 2) TN and MitoQ (n = 8; TNMitoQ), 3) HS control (n = 8; HSCon), or 4) HS and MitoQ (n = 8; HSMitoQ). Pigs were acclimated for 6 d to individual pens before study initiation. The trial consisted of two experimental periods (P). During P1 (2 d), pigs were fed ad libitum and housed in TN conditions (20.6 +/- 0.8 degrees C). During P2 (24 h), HSCon and HSMitoQ pigs were exposed to continuous HS (35.2 +/- 0.2 degrees C), while TNCon and TNMitoQ remained in TN conditions. MitoQ (40 mg/d) was orally administered twice daily (0700 and 1800 hours) during P1 and P2. Pigs exposed to HS had increased rectal temperature, skin temperature, and respiration rate (+1.5 degrees C, +6.8 degrees C, and +101 breaths per minute, respectively; P < 0.01) compared to their TN counterparts. Acute HS markedly decreased feed intake (FI; 67%; P < 0.01); however, FI tended to be increased in HSMitoQ relative to HSCon pigs (1.5 kg vs. 0.9 kg, respectively; P = 0.08). Heat-stressed pigs lost BW compared to their TN counterparts (-4.7 kg vs. +1.6 kg, respectively; P < 0.01); however, the reduction in BW was attenuated in HSMitoQ compared to HSCon pigs (-3.9 kg vs. -5.5 kg, respectively; P < 0.01). Total gastrointestinal tract weight (empty tissue and luminal contents) was decreased in HS pigs relative to their TN counterparts (6.2 kg vs. 8.6 kg, respectively; P < 0.01). Blood glucose increased in HSMitoQ relative to HSCon pigs (15%; P = 0.04). Circulating non-esterified fatty acids (NEFA) increased in HS compared to TN pigs (P < 0.01), although this difference was disproportionately influenced by elevated NEFA in HSCon relative to HSMitoQ pigs (251 mu Eq/L vs. 142 mu Eq/L; P < 0.01). Heat-stressed pigs had decreased circulating insulin relative to their TN counterparts (47%; P = 0.04); however, the insulin:FI ratio tended to increase in HS relative to TN pigs (P = 0.09). Overall, circulating leukocytes were similar across treatments (P > 0.10). Plasma C-reactive protein remained similar among treatments; however, haptoglobin increased in HS relative to TN pigs (48%; P = 0.03). In conclusion, acute HS exposure negatively altered animal performance, inflammation, and metabolism, which were partially ameliorated by MitoQ.