Topic:Animal Study
Animal studies involving horses encompass a wide range of research activities aimed at understanding various aspects of equine biology, behavior, health, and management. These studies can include investigations into equine physiology, nutrition, reproduction, and disease processes. Research often involves controlled experiments or observational studies to gather data on how horses respond to different interventions, environments, or management practices. This topic includes peer-reviewed research studies and scholarly articles that explore methodologies, findings, and implications of animal studies in equine science, contributing to the broader understanding of horse welfare and management.
Effect of Croton lechleri sap-based topical treatment, with or without nitroglycerin, on healing of equine metatarsal skin wounds. Skin wounds in horses, particularly in the distal extremities, often heal slowly due to mechanical stress, compromised perfusion, and excessive fibroplasia. This study evaluated the effects of topical Croton lechleri (CL) cream, alone or in combination with nitroglycerin, on the healing of skin wounds in the metatarsal region of horses. Six mares received six standardized wounds in each region and were treated with: saline solution, nitroglycerin (0.1 or 1 mg/mL), CL (1 or 10 µg/mL), or CL + nitroglycerin (10 µg/mL + 1 mg/mL). Wound contraction, histology, and bacterial culture were evaluate...
Obtention and preliminary clinical evaluation of an equine albumin for intravenous administration in adult Colombian Creole Horses (Equus ferus caballus). Albumin is one of the most abundant and physiologically important blood protein in horses due to its ability to regulate vascular volume and transport blood metabolites or drugs. Despite the importance of this protein, in Colombia there is no previous reference of the use of equine albumin in horses as a pharmacological therapy and there is no available any pharmaceutical preparation of this protein to be administrated in horses. This study aims to evaluate for first time the preliminary clinical response of healthy adult Colombian Creole horses after the intravenous administration of an equin...
Influence of parasitic load, breed, age, housing and season on skin and hair coat condition in horses. Strongyles are nematode parasites that affect the large intestine and cecum of the horse, with symptoms ranging from poor hair coat to colic. This can influence gut health, nutrient absorption, and overall body condition. Objective: Determine the effects of parasitic load, breed, age, housing, and season on skin and hair coat conditions. We hypothesized that horses with low fecal egg counts would have better hair and skin coat condition compared with those with high fecal egg counts. Methods: A total of forty-five Morgan and 11 Thoroughbred horses were included in this study. We tested the eff...
Metabolomics reveals early predictors of blastocyst formation in equine ICSI-derived embryos. Equine in vitro embryo production (IVP) via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) has gained prominence in sport-horse breeding due to high success rates, efficient semen utilization, and year-round embryo production, including from mares with fertility challenges or postmortem. However, assessing viability of early-stage ICSI-produced equine embryos remains challenging due to subjective morphological evaluations and limited visibility of developmental features. Non-invasive metabolomic analysis of culture media offers a promising alternative to enhance embryo selectio...
Transthoracic impedance in adult Thoroughbred horses is similar to other species. To determine transthoracic impedance (TTI) in adult horses using an exponential biphasic defibrillator and investigate patient and technique factors influencing TTI. Unassigned: A randomized crossover design with 2 phases was used. Phase 1: TTI was measured in dorsal and lateral recumbency, with and without manual pressure on the electrodes in deceased horses immediately following euthanasia. Phase 2: TTI was measured in dorsal recumbency during inspiration and expiration using anesthetized live horses sourced from 2 terminal studies. Mixed-effects linear regression modeling was performed to a...
Utility of dynamic preload indices of hypovolemia in isoflurane-anesthetized horses. To evaluate the utility of the dynamic indices, systolic pressure variation (SPV%), pulse pressure variation (PPV%) and plethysmographic variability index (PVI%) during induced hypovolemia, and to determine their correlation with cardiac output (CO) in anesthetized horses. Methods: Prospective experimental study. Methods: A group of eight healthy adult research horses. Methods: After sedation with intravenous (IV) xylazine, anesthesia was induced with IV ketamine and diazepam and maintained with constant-dose isoflurane delivered in 100% oxygen. Horses were positioned in dorsal recumbency, par...
Physiological adaptations to 6 weeks of high-intensity interval and moderate-intensity continuous training in horses: A randomized crossover study. This study tested the hypothesis that 6 weeks of high-intensity interval training (HIIT) would induce greater physiological adaptations than moderate-intensity continuous training (MICT) in Thoroughbred horses. Seven untrained horses completed two distance-matched treadmill training protocols (three sessions per week) in a randomized crossover design, separated by a three-month washout: MICT (6 min at 70% ) and HIIT (6 × [30 s at 100% with 30 s at 30% ]). Incremental exercise tests were conducted at weeks 0, 3, and 6 to assess exercise performance and physiological responses. M...
Functional and histopathologic evidence of laryngeal reinnervation using the spinal accessory nerve in horses. To evaluate functional and histopathologic outcomes of standing selective laryngeal reinnervation using the spinal accessory nerve (SAN) in horses with experimentally induced recurrent laryngeal neuropathy (RLN). Methods: Five Thoroughbred mares. Methods: Prospective cohort study. Methods: The horses underwent left recurrent laryngeal neurectomy followed 8 weeks later by selective laryngeal reinnervation using the SAN. Follow-up evaluations at 4.5, 6, 8, and 12 months included treadmill exercising endoscopy, ultrasonography of intrinsic laryngeal muscles, and percutaneous electrical stimul...
Optimising Camera-ChArUco Geometry for Motion Compensation in Standing Equine CT: A CT-Motivated Benchtop Study. Standing equine computed tomography (CT) acquisitions are susceptible to residual postural sway, which can introduce view-inconsistent motion and degrade image quality. External optical tracking based on ChArUco fiducials is a promising, low-cost strategy to enable projection-wise motion compensation, yet quantitative guidance on how camera-marker geometry affects pose-estimation performance remains limited. This CT-motivated benchtop study characterizes how the relative camera-ChArUco configuration influences both the accuracy (bias with respect to ground truth) and the precision (repeatabili...
Effect of palmar digital perineural analgesia (as a model for “nerving”) on forelimb loading over varied surfaces at the walk and trot – a pilot study. Navicular syndrome is characterized by palmar foot pain and is a common cause of lameness in horses. Palmar digital neurectomy (nerving) removes sensation to the heel region of the hoof and may serve as a treatment for navicular-afflicted horses, while analgesia (blocking) results in temporary loss of sensation. Objective: The purpose of this pilot study was to examine the effect of loss of sensation in the heel on the forelimb area and force while tracking on soft and hard ground at the walk and trot. Methods: Three horses that scored a 0 or 1 on the AAEP lameness scale were fitted to Tekscan...
Ertapenem Pharmacokinetics in Equine Plasma and Synovial Fluid Following a Single Intravenous Dose. This study describes the pharmacokinetics of ertapenem, a carbapenem antimicrobial that has not been previously studied in equids. Administered as a 30 mg/kg intravenous bolus to six healthy horses, serial blood and synovial samples were obtained over 8 h after administration. Pharmacokinetic analysis of plasma and synovial fluid was performed. In plasma, the AUC was 353.10 h × μg/mL (CV = 49.02%), Vss 79.34 mL/kg (CV = 22.85%), CL 84.96 mL/h/kg (CV = 31.31%) and t1/2 2.03 h (CV = 15.32%). In synovial fluid, the AUC was 524.10 h × μg/mL (CV = 16.03...
TGF-β1 and estradiol modulate prostaglandin concentrations and related gene expression in equine endometrium during the follicular phase. Transforming growth factor (TGF)-β1 is a pro-fibrotic cytokine that affects extracellular matrix (ECM) deposition and fibroblast activity. 17β-Estradiol (E), the dominant ovarian steroid during the follicular phase (FLP) of the estrous cycle, can also influence ECM remodeling and fibrosis, through prostaglandin (PG) synthesis. PGs have opposing roles in fibrosis, with PGE₂ showing anti-fibrotic effects and PGF₂α promoting fibrosis. Equine endometrosis, whose main pathological feature is fibrosis, is marked by chronic inflammation and ECM accumulation, and may involve mediators like TGF-...
Comparative Evaluation of Follicular Flushing Frequency and Scraping Time During Ovum Pick-Up in Mares: Effects on Oocyte Recovery Rate and Technical Considerations. Transvaginal ultrasound-guided follicular aspiration or ovum pick-up (OPU) has become the standard technique for oocyte collection in mares for intracytoplasmic sperm injection (ICSI). Although repeated follicular flushes and wall scraping are commonly used to improve oocyte recovery rate (ORR), the relative contribution of each remains unclear. This study aimed to compare the effects of multiple flushes versus controlled scraping time on ORR in mares. A controlled trial was conducted in two phases: (1) an ex vivo phase using slaughterhouse ovaries (n = 32), and (2) an in vivo phase in c...
Diet composition influences equine large intestinal motility as measured by transcutaneous ultrasound. To quantify gastrointestinal motility at 3 anatomic locations of the large colon in healthy horses fed 2 diets. Unassigned: 12 American Quarter Horses were enrolled in a prospective crossover study. Horses received either a complete pelleted diet fed at 1.35% body weight (BW) per day or Coastal Bermudagrass hay fed at 2% BW with 0.5% to 0.7% BW of complete pelleted feed. Each diet was fed for 13 days prior to motility assessment. Two ultrasonographers recorded the frequency of contractions at the sternal flexure of the large colon, left ventral colon, and cecum for 4 consecutive, 1-minute peri...
Blood and fecal metabolic responses of mature horses fed rhizoma peanut hay. Rhizoma peanut (RP, Arachis glabrata Benth) is an alternative legume forage to alfalfa (ALF, Medicago sativa L.) with less non-structural carbohydrates and crude protein. Yet, metabolic responses to consuming RP hay have never been evaluated in horses. Objective: The objective of this study was to investigate the effect of feeding RP 'Florigraze' hay on fecal and blood metabolic variables compared to alfalfa 'Legendary XHD' and bermudagrass (BMG, Cynodon dactylon L. 'Coastal') hays fed to maintenance horses. Methods: Six mature Quarter Horse geldings (596±40 kg) were randomly assigned to one ...
Sex-Related Differences in Show-Jumping Performance of Retired Thoroughbred Racehorses in Relation to the Interval Since Race Retirement. To investigate the factors affecting the utilization of retired Thoroughbred racehorses in equestrian disciplines, Bayesian linear mixed models were separately fitted using rank, round time, and obstacle faults from show-jumping competitions restricted to retired Thoroughbred racehorses as dependent variables, with the interaction between horse sex and the interval from race retirement to competition (as a proxy for transition training to show-jumping) as a fixed effect. When the interval was short (≤1 year), the estimated marginal mean of rank was statistically significantly lower in stalli...
Tissue-Engineered Osteochondral Allograft Versus Fresh Osteochondral Allograft: Comparable Cartilage and Subchondral Bone Repair in a 14-Month Equine Osteochondral Defect Model. Fresh osteochondral allograft (OCA) transplantation effectively repairs cartilage and subchondral bone; however, the persisting shortage of available donor OCAs and their short shelf-life make scheduling surgeries and meeting patient demand challenging. Attempts have been made to develop tissue-engineered solutions to address the limitations of OCA; nonetheless, these have failed to progress beyond the preclinical stage. Objective: To assess the safety and efficacy of a tissue-engineered osteochondral allograft (TE-OCA) as compared with equine OCA in an equine osteochondral defect model. Metho...
A novel oral immunotherapy strategy using transgenic barley induces Culicoides allergen-specific immune responses in horses. Insect bite hypersensitivity (IBH) is a seasonal, IgE-mediated allergic dermatitis of horses caused by salivary gland proteins of biting midges ( spp.). Current management relies on relief of clinical signs and on physical protection. In a previous pilot study, healthy horses were fed transgenic barley expressing a allergen via a special spiral bit, which successfully induced allergen-specific antibody responses. Building on this concept, the present study aimed to evaluate a more practical feeding approach, delivering transgenic barley expressing the major allergen Cul o 2p in a feed-compat...
Where Dinner Roams: The Role of Feral Horses as a Resource Subsidy for Wolves and Cougars in West-Central British Columbia. Feral horses () have established large populations in west-central British Columbia (BC), Canada, where they overlap with native ungulates, including a declining woodland caribou () herd. In addition, feral horses co-occur with large carnivore species including wolf () and cougar (). Feral horses may act as a resource subsidy for predators, potentially altering predator-prey dynamics, yet empirical observations of predator interactions with feral horses are scarce in Canada. Between 2019 and 2025, we documented 21 instances of wolf predation or scavenging of feral horses, including one direct ...
Spirulina supplementation regulates inflammation and supports cartilage health in adult sedentary horses following moderate-intensity exercise. Horses experience rapid physiological, inflammatory, and oxidative responses during exercise. Spirulina, a nutrient-dense microalga with antioxidant and anti-inflammatory properties, may help modulate these responses and support recovery. Objective: This study evaluated the effects of 30-day dietary Spirulina supplementation on physiological, inflammatory, and oxidative stress responses to moderate-intensity exercise in sedentary horses. We hypothesized that 30-day Spirulina supplementation would modulate hematologic and inflammatory responses and support recovery from moderate-intensity exerc...
RNA-seq evaluation of equine alveolar macrophages and monocyte-derived macrophages exposed to an inflammatory stimulus (short communication). Macrophage populations in the lung, including resident alveolar macrophages (AMs) and recruited monocyte-derived macrophages (MDMs), recognize the inhaled particulates in barn dust that cause severe equine asthma and orchestrate an immune response though the cytokines they produce. Despite their importance, the specific contributions of these macrophage subsets to lower airway inflammation remain poorly understood. This exploratory in vitro study investigated the likely contributions of AMs and MDMs from healthy horses to the early inflammatory response using RNA-seq. If biologically importan...
Differential profiles of GH, IGF-1, and fructosamine in follicular fluid and plasma of cyclic mares. Growth hormone (GH) influences follicular development mainly by stimulating insulin-like growth factor 1 (IGF-1), which acts systemically and locally within the ovary. However, the metabolic profile of follicular fluid (FF) in mares, particularly markers such as fructosamine (FRUCT), an indicator of glucose metabolism, remains poorly characterized. This study aimed to evaluate GH, IGF-1, and FRUCT concentrations in plasma and FF and their variation across follicle sizes. Sixty ovaries were collected during the breeding season from 30 clinically normal mares raised for meat production. Blood sa...
Nicotinic acid treatment improves the developmental potential of equine oocytes for cloned embryo production. Nicotinic acid (NA) treatment during in vitro maturation (IVM) has been shown to elevate nicotinamide adenine dinucleotide (NAD) levels and improve oocyte developmental competence. Suboptimal equine oocyte IVM systems currently limit the efficiency of viable embryo in vitro production. This study evaluated NA supplementation during IVM for cloned equine embryo production, using oocytes from abattoir-sourced ovaries and live mares via ovum pick-up (OPU). Abattoir-derived oocytes (n = 694) were treated without or with 50 or 200 μM NA during the 18 h holding period (Pre-IVM). Next, OPU-deriv...
Amniotic Mesenchymal Stromal/Stem Cell-Derived Extracellular Vesicles for Equine Chronic Degenerative Endometritis Treatment. Equine chronic degenerative endometritis (CDE) is a progressive process characterized by endometrial fibrosis that could be responsible for alterations of uterine environment and foetal-maternal communication. Objective: The aim of this study was to try to restore this communication by intrauterine administrations of amniotic cell-derived extracellular vesicles (AMC-EVs) in a case series. Methods: Twelve mares were selected on the basis of their reproductive history of early embryonic loss or abortion and clinical suspicion of CDE subsequently verified with histopathological examination of end...
Pharmacopuncture with low-dose dexmedetomidine and saline aquapuncture at acupoint Governing Vessel 24 provides sedation in healthy adult horses. To evaluate sedation in horses following pharmacopuncture with dexmedetomidine at acupoint Governing Vessel 24 (GV-24) compared to aquapuncture at GV-24 or an equivalent dose of dexmedetomidine administered via IV or SC routes. Unassigned: 10 adult mares received 4 treatments in a blinded, randomized, crossover design: (1) dexmedetomidine administered at GV-24 (DexmedGV24; 1 μg/kg); (2) saline administered at GV-24 (SalineGV24; 1.5 mL); (3) dexmedetomidine administered SC on the lateral neck (DexmedSC; 1 μg/kg); or (4) dexmedetomidine administered IV (DexmedIV; 1 μg/kg). Sedation scores (fa...
Effects of intravenous oxytocin on plasma serotonin and trainability in horses. Oxytocin (OXT) plays a crucial role in regulating the serotonin (5-HT) system and behavior. Although previous studies have reported significant relationships among OXT, 5-HT, and behavioral responses, the effects of OXT on 5-HT concentrations and behavioral traits in horses remain poorly understood. This study aimed to investigate the effects of intravenous OXT administration on plasma 5-HT concentrations and trainability in horses. A crossover design was employed using eight horses, each receiving either a 10-IU intravenous dose of OXT or normal saline. Blood samples were collected at baselin...
Chlorhexidine is Superior to Ozonized Water in the Reduction of the Oral Cavity Microbiota of Horses. In equine husbandry, oral cavity procedures are commonly performed and may be associated with complications, including extraoral diseases, potentially resulting from bacterial contamination and inadequate antisepsis. Bacterial resistance to antimicrobials is a major issue for healthcare professionals, including veterinarians that may misuse these pharmaceuticals. Therefore, developing novel methods for antisepsis is desirable. This study aims to test the effectiveness of a 100 µg/ml ozonized injectable water solution versus 0.12% chlorhexidine mouthwash. Fifty adult equines had swab samples...
Activation of the S100A8/A9 Alarmin Amplifies Inflammatory Pathways in Equine Ascending Placentitis. Ascending placentitis is a significant cause of equine pregnancy loss, yet the upstream inflammatory triggers are poorly defined. Recently, we identified S100A8/S100A9 (S100A8/A9) alarmins as potential upstream regulators in a chronic equine placentitis model. The current study aimed to determine whether this upregulation is sustained in the acute model and in clinical cases, and to elucidate the expression of their downstream inflammatory mediators. Using an experimental model, we quantified mRNA expression in acute ( = 5) and chronic ( = 6) placentitis induced by ssp. . We found mRNA expre...
Early Iron Age horse exploitation in Thrace (Bulgaria) inferred from dental attrition and vertebral pathology. To assess pathological lesions observed in an Early Iron Age (8th-century BCE) horse to gain insight into equine use and management in the past. Methods: The study is based on a nearly complete adult horse skeleton recovered from a pit at an archaeological site near Chirpan, Thracian Valley, southern Bulgaria. The assemblage is radiocarbon dated to the 8th century BCE and represents one of the few well-documented Early Iron Age equine skeletons from Bulgaria. Methods: Preserved skeletal elements were examined macroscopically following standard zooarchaeological and palaeopathological protocols...
Ultrasonographic Evidence of Synovitis Correlates with Synovial Citrate and TBARS in Equine Osteoarthritis. Osteoarthritis (OA) is a degenerative joint disease that affects humans and animals worldwide. Its early diagnosis remains challenging due to subtle clinical signs and late radiographic changes. This study aimed to explore candidate biomarkers associated with spontaneous OA and to investigate their correlation with ultrasonographic scores to support early diagnosis. Clinical, radiographic, and ultrasonographic evaluations were performed on 52 equine metacarpophalangeal joints, with and without OA, allowing joint scoring and classification into osteoarthritis (OAG) and control groups. Synovial ...