Journal of Equine Veterinary Science最新文献

{"title":"Differential gene expression in pre-race blood samples from racehorses with race-day fractures","authors":"A.M. Rauber-Ramos ,&nbsp;B.C. Menarim ,&nbsp;S.C. Loux ,&nbsp;A.E. Page","doi":"10.1016/j.jevs.2025.105457","DOIUrl":"10.1016/j.jevs.2025.105457","url":null,"abstract":"<div><div>Catastrophic musculoskeletal injuries (CMI) are a major concern in Thoroughbred horse racing, with identification of screening methods for horses at risk of injury being a top research priority. Postmortem exams have found the majority of these injuries to be associated with chronic accumulation of microdamage, which would theoretically produce localized and systemic changes detectable via biomarker analysis. Previous research using post-injury and post-race samples found increased messenger RNA (mRNA) expression of IGF1 and MMP2 and decreased expression of IL1RN in horses with CMI compared with controls. However, differences in mRNA expression immediately before injury, where there is no influence of exercise and/or the acute injury, have not been assessed. As such, to identify differentially expressed genes potentially associated with CMI, a total of 15,463 pre-race whole-blood samples were collected in Tempus Blood RNA Tubes over an 18-mo period. RNA sequencing of select samples was subsequently used to investigate transcriptional differences between 12 cases (fatal and nonfatal fractures) and 93 race-matched controls. Across all fractures, 31 genes were downregulated and 3 were upregulated. In phalanx and metacarpal fractures, there were 838 downregulated and 223 upregulated genes; in sesamoid fractures, there were 293 downregulated and 67 upregulated genes; and in hock and carpal fractures, there were 76 downregulated and 4 upregulated genes. CXCL1 and IL6 were downregulated in horses with long bone fractures, with these genes having been previously linked with adaptation to exercise. ANK2, a key regulator of bone mineralization that is increased during fracture healing, and SLIT3, a gene associated with production of fibrillar collagen, were downregulated in all fracture types and especially long bone fractures, consistent with a failure of proper bone remodeling before fracture. Integrative pathway analysis revealed a variety of pathway changes, including a downregulation of osteoclastic pathways in long bone and sesamoid fractures and of bone mineralization pathways in long bone fractures. These results continue to indicate that whole-blood mRNA samples may be useful in identifying racehorses with maladaptive bone remodeling responses, increasing their risk of fracture.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105457"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationships between muscle atrophy scores, body mass, and fat-free mass in mature horses","authors":"C. Carlson,&nbsp;A.C. Herbst,&nbsp;K. Malinowski,&nbsp;K.H. McKeever","doi":"10.1016/j.jevs.2025.105478","DOIUrl":"10.1016/j.jevs.2025.105478","url":null,"abstract":"<div><div>Various diseases, malnutrition, detraining, and aging can cause muscle atrophy in horses. Although even small reductions in muscle mass can adversely affect performance, larger losses can significantly impair a horse's welfare due to decreased strength. Thus, routine muscle mass monitoring is important to detect changes in muscle mass early when they are most treatable. The equine muscle atrophy scoring system (MASS) is a standardized muscle scoring system with good interrater reliability. However, the system is currently not fully validated, and relationships to other body composition measurements are not fully understood. The objectives of this study were therefore to assess the relationships between muscle atrophy scores (MAS), body mass (BM), and fat-free mass (FFM; a muscle mass indicator) at individual measurement time points (objective 1) and over time (objective 2). We hypothesized that MAS, BM, and FFM were significantly associated across measurement time points, and that changes in these parameters over time were also related. Linear mixed-effects models were used for data analysis. Nine Standardbreds (n = 4 geldings and n = 5 mares) aged between 13 and 21 years were used. The horses had Henneke body condition scores between 4.5 and 5.75, weighted 430 kg to 547 kg, were not in work, and received a diet consisting of ad libitum hay and pasture. The horses’ BMs and ultrasound-based FFMs were obtained, and the horses were scored for muscle atrophy (higher scores indicating more atrophy) by the same experienced rater. BM and MAS were recorded a total of 8 times over 10 wk, with a minimum of 7 d between data recordings. FFM was recorded 3 times, at the start, in the middle, at the end of the study, and on the same days on which the other parameters were recorded. There was no significant association between the horses’ neck and hind region MAS and their BM or FFM (<em>P</em> &gt; 0.05), but the horses’ MAS of the back region were positively related to BM (<em>P</em> &lt; 0.001) and FFM (<em>P</em> &lt; 0.01). BM and FFM were significantly correlated (<em>P</em> &lt; 0.001). There was no significant association between the changes in MAS in any body region and the changes in the horses’ BMs or FFMs over time (<em>P</em> &gt; 0.05). The maximal changes in BM and FFM between 2 time points were 3.6% and 4.1%, respectively. This study suggests that the MASS is not sensitive enough to detect very small changes in BM or FFM over time. The findings of this study also suggest that ultrasound-based FFM may be biased by BM, and that BM, measured at a single time point, may not be a good marker for normal muscle mass, even within horses of similar body size, as higher MAS were not related to lower BM.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105478"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 bisphosphonate administration on synovial metabolome of juvenile horses challenged with intra-articular lipopolysaccharide","authors":"J.M. George ,&nbsp;J.L. Leatherwood ,&nbsp;A.N. Bradbery ,&nbsp;C.E. Arnold ,&nbsp;K.G. Glass ,&nbsp;B.L. Paris ,&nbsp;M.B. Conrad ,&nbsp;R.E. Martinez ,&nbsp;A.S. Reiter ,&nbsp;C.R. Kerth ,&nbsp;T.H. Welsh Jr.","doi":"10.1016/j.jevs.2025.105511","DOIUrl":"10.1016/j.jevs.2025.105511","url":null,"abstract":"<div><div>The objective of this study was to evaluate the synovial metabolome in juvenile exercising horses treated with the bisphosphonate clodronate disodium (OSPHOS®) following an intra-articular lipopolysaccharide (LPS) challenge. Treatment groups consisted of 8 control horses that received saline injections (CON) and 8 horses that received clodronate disodium (CD; 1.8 mg/kg BW, IM) on d 0, 42, 84, and 126 of a 140-d study. Horses underwent a progressive exercise regimen that culminated with an intra-articular LPS challenge on d 126. Radial carpal joints of each horse were injected with 0.8 mL of either 0.5 ng LPS derived from <em>Escherichia coli</em> O55:B5 or sterile lactated Ringer's (LRS) solution as a contralateral control. Synovial fluid was collected before LPS injection (h 0) and 6, 12, 24, and 336 h post injection. Synovial fluid samples were extracted using 1:1 water:acetonitrile liquid-liquid extraction. Sample extracts were analyzed using high-performance liquid chromatography quadrupole time-of-flight (HPLC-qTOF) reverse-phase chromatography in positive ion mode. Significant (<em>P</em> ≤ 0.05) metabolites were compared with a list of standards by retention time, <em>m</em>/<em>z</em> ratios, and molecular features. Of the 83 significant (<em>P</em> ≤ 0.05) compounds, 58 were annotated by Wiley and National Institute of Standards and Technology metabolite libraries. Of the annotated compounds there were 14 lipid and 12 amino acid metabolites, with the remainder of unknown origin. Total metabolites of the CD and LPS treatments were segregated by partial least squares discriminate analysis. The principal component analysis discriminant analysis segregated CD and CON samples along component 1, which accounted for 89.64% of the total variation where most metabolites were upregulated in CD compared with CON. Upregulated lipid metabolites included fatty acyls, fatty esters, prenols, and sphingolipids. There was a treatment × time × carpus interaction where 6 h after LPS injection, the relative metabolite abundance was greater in CD vs. CON in the LPS joint (<em>P</em> ≤ 0.05). These metabolites included creatine (<em>P</em> = 0.03), guanosine (<em>P</em> = 0.01), and 2 amino acid metabolites (<em>P</em> = 0.01; <em>P</em> = 0.04). These results indicate that inflammatory progression stimulated by intra-articular LPS increases amino acid and lipid metabolite abundance in the synovial metabolome. Further, CD had increased lipid and amino acid metabolism compared with CON in both the LPS and LRS injected joints. Further investigation of the equine synovial metabolome is warranted in view of this initial observation that bisphosphonate administration upregulated synovial metabolite abundance.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105511"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the impact of ostarine on body composition in adult horses: A longitudinal study","authors":"A. Morocho ,&nbsp;A.C. Herbst ,&nbsp;S.H. White-Springer ,&nbsp;K. Malinowski ,&nbsp;K.H. McKeever","doi":"10.1016/j.jevs.2025.105444","DOIUrl":"10.1016/j.jevs.2025.105444","url":null,"abstract":"<div><div>The integrity of horse racing is under increasing scrutiny due to the misuse of performance-enhancing drugs that compromise fair competition and animal welfare. Among these substances, ostarine is one drug of concern. Ostarine selectively targets androgen receptors in skeletal muscle and bone and was found to enhance muscle mass in people. However, the effects of ostarine on equine physiology, and especially on muscle and fat mass, are currently poorly understood, highlighting a critical gap in research that must be addressed to inform doping regulations and safeguard the welfare of racehorses. Thus, this study aimed to investigate the effects of ostarine on muscle and fat mass in horses. We hypothesized that ostarine treatment would result in a change in muscle and fat mass compared with a control group. Nine Standardbred horses (mean age ± SD = 17.2 ± 2.5 years) were used in this study and were either assigned to the treatment group (n = 4; receiving ostarine [62 mg in 1 mL of ethanol] intravenously) or the control group (n = 5; receiving 1 mL of ethanol as a vehicle control, intravenously). Horses received the treatment/control for 4 wk 4 times a week (on nonconsecutive days) and were monitored before the treatment/control (baseline), during the treatment period and after treatment for 4 wk. The ostarine treatment duration was based on a rodent study. Measurements included body mass, ultrasound-based fat-free mass (FFM) and fat mass (FM) estimation, body condition scoring, and muscle atrophy scoring. A mixed-model ANOVA (fixed effects: group, data collection time point, and their interaction) was used to analyze differences between the groups. No significant differences between treatment and control groups were found for body mass (<em>P</em> = 0.60), FFM (<em>P</em> = 0.86), FM (<em>P</em> = 0.45), muscle atrophy scores of the horses’ hind region (<em>P</em> = 0.94), back region (<em>P</em> = 0.52), or neck region (<em>P</em> = 0.92), at any of the data collection time points. A significant group by time point interaction was found for body condition scores (<em>P</em> = 0.03); however, a post hoc Tukey test indicated no statistically significant differences between the groups at any of the sampling time points. This small study showed no significant effects of ostarine on selected muscle and fat mass indicators in adult horses, suggesting that ostarine may not affect muscle mass in idle adult horses. As this study was of small sample size it is possible that it did not have enough power to detect smaller differences between the treatment and control groups. Larger studies may explore longer durations of ostarine administration, or administration to exercising horses.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105444"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of ostarine on clinical health parameters in adult horses","authors":"C. Nealon ,&nbsp;A.C. Herbst ,&nbsp;S.H. White-Springer ,&nbsp;K. Malinowski ,&nbsp;K.H. McKeever","doi":"10.1016/j.jevs.2025.105445","DOIUrl":"10.1016/j.jevs.2025.105445","url":null,"abstract":"<div><div>Selective androgen receptor modulators, such as ostarine (also called enobosarm), are androgen receptor ligands that initiate tissue-selective activation of androgenic signaling and have demonstrated potential in enhancing muscle mass and physical performance with minimal androgenic side effects in humans. Due to its anabolic effects, ostarine is used for illegal doping in horses, presenting a problem for ethical horse racing, and possibly also for horse safety and health. There are currently no studies that investigated the effects of ostarine on equine health. Thus, the goal of this study was to investigate whether ostarine adversely effects the clinical health of horses. We hypothesized that ostarine would alter indicators of heart health, but no other clinical health parameters investigated in this study. A total of 9 idle adult horses (mean age ± SD = 17.2 ± 2.5 years) were enrolled, 4 of which received intravenous (IV) injections of 62 mg ostarine in 1 mL ethanol 4 times a week (on nonconsecutive days) for 4 weeks, while the remaining 5 horses received 1 mL of ethanol (IV) at the same times to serve as controls. The treatment duration was based on a rodent study. Clinical exams were performed by the same experienced person once before injections, weekly during the injection period, and at 2 weeks and 4 weeks postinjection. Data were analyzed descriptively and using a mixed model ANOVA with treatment group, exam day, and their interaction fitted as fixed effects. Ostarine-treated horses did not have significantly different respiratory rates (<em>P</em> = 0.76), rectal temperatures (<em>P</em> = 0.65), or heart rates (<em>P</em> = 0.37), compared with the control group at any of the recording time points. Abnormal heart sounds were only recorded once during the study in a control horse. No signs of depression or abnormal lung sounds were recorded in any of the horses throughout the study. Abdominal sounds were present, but abnormal abdominal sounds were not recorded in any of the horses during the study. These findings suggest that ostarine administration, at the dose, administration frequency and route used in this study, does not significantly alter the basic clinical health parameters investigated. While ostarine might thus be considered safe to use in idle adult horses under these conditions, there is still little understanding of its potential long-term effects, the effects on other clinical and nonclinical health parameters, as well as the effects in exercising horses. In addition, this study was of small sample size, and it is thus possible that it was not powerful enough to detect smaller, but meaningful, differences between the treatment and control groups.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105445"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic gene expression differences in emaciated and moderately conditioned horses: RNA-seq analysis of postmortem skeletal muscle","authors":"M. Parr,&nbsp;E. Shepherd,&nbsp;M. Hines,&nbsp;L. Strickland,&nbsp;T. Freeman,&nbsp;S. Moisa,&nbsp;J. Beever,&nbsp;J. Ivey","doi":"10.1016/j.jevs.2025.105489","DOIUrl":"10.1016/j.jevs.2025.105489","url":null,"abstract":"<div><div>Emaciated (E) horses maintain different metabolic profiles compared with moderately conditioned (M) horses, however, pathway knowledge in affected tissues is limited. When gene expressions across varied tissue types were assessed using RT-qPCR for gene activity related to glucose transport, protein synthesis, and fatty acid oxidation, no differential expression was identified. Euthanasia with sodium barbiturates has been cited to limit gene expression postmortem in RT-qPCR assays, leading to an identified need for alternative gene expression assessment postmortem. To investigate the hypothesis that metabolic-associated gene regulation differs between E and M, RNA sequencing (RNA-seq) assessment was employed. Eight horses (aged 20 ± 6 yr, mean ± SD) were split into 2 groups based on BCS assessed by 3 independent reviewers (1–9 scale, 1 = emaciated, 9 = obese): 4 M (BCS 4–5, 4.75 ± 0.43) and 4 E (BCS 1–2, 1.25 ± 1.43). After euthanasia via sodium barbiturate overdose, middle gluteal skeletal muscle samples were collected from each horse, flash frozen in liquid nitrogen and stored at −80°C until RNA-seq assessment. Differential expression analysis was performed using the limma-voom method due to its reliable inference in experiments with limited numbers of replicates (R 4.4.2). Principal component analysis and correlation analysis between samples revealed differences in gene expression profiles between emaciated and moderately conditioned samples. Differential expression analysis for emaciated versus moderately conditioned animals identified 817 differentially expressed genes (DEGs), with 243 upregulated and 574 downregulated (FDR adjusted <em>P</em> &lt; 0.05). Furthermore, this data recapitulates RT-qPCR findings previously reported specific to glucose, protein, and fatty acid metabolism where no differential expression in RNA-seq results were identified. Functional enrichment analysis discovered overrepresented metabolic pathways in DEGs (FDR adjusted <em>P</em> &lt; 0.05), including glucose metabolism, oxidative phosphorylation, and ATP synthesis, as well as mitochondrial functions. Issues identified while using RT-qPCR in postmortem samples could be modulated by using RNA-seq, and preliminary results indicate biologically relevant discoveries are possible even in cases where expectations for specific genes are not met. Due to unique, tissue-specific metabolic pathways, continued RNA-seq analysis of equine tissues, both in antemortem and postmortem samples, may allow a better understanding of metabolic differences between E and M horses.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105489"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of an oral chondroprotective joint supplement on stride length and lameness in aged geldings with osteoarthritis","authors":"R.M. Harbowy,&nbsp;C.I. Robison,&nbsp;B.L. Boger,&nbsp;J.M. Manfredi,&nbsp;B.D. Nielsen","doi":"10.1016/j.jevs.2025.105453","DOIUrl":"10.1016/j.jevs.2025.105453","url":null,"abstract":"<div><div>With osteoarthritis (OA) diagnosed in over 50% of horses aged 15 years or older, there is a drive within the industry to prevent, mitigate, or repair joint damage. As such, oral joint supplements (OJS) are one of the most popular feed additives fed by horse owners. Though extensively reviewed in in vitro studies, conclusive evidence of the efficacy of these nutraceuticals in vivo has yet to be found. Hypothesizing that OJS do not improve signs of OA, this study aimed to investigate the impacts of OJS on equine lameness. To do so, 40 geldings (aged 18 ± 7 yr) with OA and AAEP lameness grades between 2 and 4 (as scored by a board-licensed veterinarian) were enrolled in the study. Horses were striated by lameness grade, BCS, and weight, and then were randomly assigned to receive a placebo powder or OJS containing glucosamine hydrochloride, methylsulfonylmethane, sodium chondroitin sulfate, and avocado/soybean unsaponifiables added to a ration balancer for 6 wk. Both the ration balancer and OJS were fed according to product instructions. Placebo and OJS groups were color-coded to ensure researchers remained blinded to treatment, and horses were assigned a random numeric identifier to prevent bias. Stride length (SL) measurements, flexion tests (FT), and lameness locator (LL) assessments were performed every 2 wk. Statistical analysis was performed using PROC MIXED in SAS 9.4 with the fixed effect of treatment, day, treatment by day, and random effect of horse. Day 0 was a significant covariate for LL data and was included in the model. There was no effect of treatment or treatment by day interaction for SL, though day affected both walk (<em>P</em> = 0.04) and trot (<em>P</em> &lt; 0.01). However, across days, all changes in stride length were within 3% of baseline measurements. Similarly, there was no effect of treatment or the interaction of treatment by day for FT scores. Day affected FT scores, with the lowest average score on d 28 (<em>P</em> = 0.04). Analysis of lameness locator data showed no evidence of supplementation improving forelimb or hindlimb lameness over time, though hindlimb lameness tended to differ on d 14, with OJS horses having greater indication of lameness (<em>P</em> = 0.09). Thus, 6 wk of feeding an OJS did not impact stride length, lameness, or gait symmetry though values of each measure changed over time regardless of treatment. As such, there is no evidence to support efficacy of the tested OJS. These results emphasize the importance of well-controlled studies to determine the OJS efficacy in vivo and support the continued development of evidence-based management strategies for horses diagnosed with OA.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105453"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2025 equine science society symposium: Come for the science, stay for the people","authors":"Krishona Martinson ,&nbsp;Stephen Coleman","doi":"10.1016/j.jevs.2025.105424","DOIUrl":"10.1016/j.jevs.2025.105424","url":null,"abstract":"","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105424"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 stallion sperm quality post-thaw: Effects of selection methods on concentration, motility, and mitochondrial activity","authors":"C.A. Covarrubias ,&nbsp;K.J. Stutts ,&nbsp;K.V. Flores ,&nbsp;T.B. Nelson ,&nbsp;M.K. Blythe ,&nbsp;R.E. Martinez","doi":"10.1016/j.jevs.2025.105467","DOIUrl":"10.1016/j.jevs.2025.105467","url":null,"abstract":"<div><div>The commercial use of frozen-thawed equine semen for foal production is a well-established clinical practice. However, to address infertility issues in some stallions, sperm selection techniques are essential for improving semen quality. This study aimed to evaluate the quality of post-thaw sperm processed using either a density gradient (EquiPure; NidaCon International AB, Sweden) or a microfluidic device (VetMotl; VetMotl Inc., Gaithersburg, MD, USA). Frozen-thawed semen from 6 stallions was analyzed with 2 replicates per stallion. Thawed straws were diluted 1:2.5 with Botusemen® Gold (Botupharma USA, Phoenix, AZ, USA) and aliquoted into their respective selection methods (control, EquiPure, or VetMotl) for processing. The thawed sperm were assessed for concentration (CONC; 10⁶/mL), total motility (TMOT), progressive motility (PMOT), and active mitochondria measured by double-stain fluorescence assay (H33342/Rhodamin123) using a computer-assisted sperm analyzer (CASA; AndroVision®, Minitube International, Verona, WI, USA). Statistical analysis was performed using the mixed model of SAS V9.4, with stallion included as a random effect to account for variability between individual stallions. Statistical significance was set at <em>P</em> &lt; 0.05, and trends noted at <em>P</em> &lt; 0.10. A significant effect on mean CONC was observed (<em>P</em> = 0.0004). VetMotl exhibited a significantly lower mean CONC (70.925 ± 77) compared with both the control (350.05 ± 77) and EquiPure (266.39 ± 77). There was no difference in TMOT between processing methods (<em>P</em> = 0.1118). Interestingly, an overall difference was observed for PMOT (<em>P</em> = 0.0038). The control method had a lower mean percentage of PMOT (38.5 ± 7) compared with both EquiPure (49.5 ± 7) and VetMotl (56.7 ± 6). However, no difference in PMOT was observed between EquiPure and VetMotl (<em>P</em> = 0.1226). Furthermore, there was a difference in active mitochondria (<em>P</em> = 0.0003). VetMotl had a greater mean percentage of active mitochondria (40.5 ± 7) compared with both the EquiPure (15.8 ± 3; <em>P</em> &lt; 0.0001) and the control (23 ± 3; <em>P</em> = 0.0012). Overall, this study highlights the differential impact of sperm selection methods on the quality of post-thaw equine spermatozoa. While VetMotl showed advantages in terms of active mitochondria, it did not outperform EquiPure in PMOT. These findings suggest that both methods have distinct benefits and may be utilized based on specific criteria for improving semen quality in equine reproductive practices.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105467"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of meal frequency on outdoor, group-housed horse behavior, social hierarchy, and stress","authors":"E.R. Share ,&nbsp;S.L. Mastellar ,&nbsp;J.A. Pempek ,&nbsp;K. Bennett-Wimbush ,&nbsp;J.K. Suagee-Bedore ,&nbsp;N.R. Liburt ,&nbsp;A. Krotky ,&nbsp;B. Cassill ,&nbsp;P. Harris ,&nbsp;M.L. Eastridge","doi":"10.1016/j.jevs.2025.105462","DOIUrl":"10.1016/j.jevs.2025.105462","url":null,"abstract":"<div><div>Social interactions with conspecifics and prolonged foraging behavior promote equid welfare. However, resource availability and feeding method can affect aggression observed in group-housed horses. The objective of this study was to investigate effects of meal frequency on equine behavior, social hierarchies, and welfare. Horses (n = 12) were assigned to one of 2 pens, blocked by body condition score, breed type, age, and sex. Horses were group-housed in 40 × 40 m dry lots with shelters. After a 14-d diet adaptation, pens were randomly assigned an order of meal frequencies in a crossover design and fed once (1 ×, 0800 h), twice (2 ×, 0800 and 1800 h), or 3 times (3 ×, 0800, 1300, and 1800 h) per day for 7 d per treatment. Each pen was fed grass hay at 1.55% of body weight (BW) per day on a dry matter (DM) basis from 7 slow-feed hay nets, approximately 15 min before the pelleted meal. Pelleted, complementary concentrate was fed at 0.45% BW DM per day via individual nosebags. Total rations were divided equally across meals (1 ×, 2 ×, or 3 ×). On d 5 of each treatment, horses were video recorded for continuous observation for 2 h centered around the 0800 h pelleted meal. Behaviors were categorized using an ethogram for frequency (bouts) for all behaviors and duration (%) for select behaviors. Time budgets were calculated for pre-feeding (before hay), post-feeding (after hay), and total time. Dominance ranks within pen were based on displacements given and received. Fecal samples were collected on d 5 for cortisol/corticosterone metabolite (FCM) measurement as an indicator of stress. Data were analyzed using PROC MIXED in SAS with meal, pen, and dominance rank as fixed effects and random effects of period and horse nested within pen. Horses fed 3 × (24 ± 3 bouts) stood alert more frequently (<em>P</em> &lt; 0.0001) than horses fed 1 × (19 ± 3 bouts) or 2 × (12 ± 3 bouts). Pre- but not post-feeding, horses assigned a higher dominance rank showed signs of aggression (e.g., ears back, biting) more frequently (<em>P</em> = 0.03). More signs of aggression were seen post-feeding (<em>P</em> = 0.03) when horses were fed 3 × (11 ± 2 bouts) compared with 1 × (6 ± 2 bouts). Post-feeding, horses fed 3 × walked more frequently (24 ± 3 bouts) compared with those fed 1 × (19 ± 3 bouts) or 2 × (18 ± 3 bouts; <em>P</em> = 0.03), and horses were displaced more frequently when fed 3 × (10 ± 2 bouts) compared with 1 × (6 ± 2; <em>P</em> = 0.05). Meal frequency and dominance rank did not influence FCM concentrations. Overall, increased incidences of aggression occurred when group-housed horses were fed smaller, more frequent meals.</div></div>","PeriodicalId":15798,"journal":{"name":"Journal of Equine Veterinary Science","volume":"148 ","pages":"Article 105462"},"PeriodicalIF":1.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}