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 heat acclimation training frequency on the physiological adaptations of Thoroughbred horses. Heat acclimation enhances thermoregulation and cardiovascular function. While daily training protocols are typically recommended for humans, optimal training protocols for Thoroughbred horses remain unclear. Here, we compared the effects of two heat acclimation protocols, consecutive and intermittent, in Thoroughbred horses. In a randomized crossover study, eight trained Thoroughbred horses completed either a consecutive (CONS: 9 consecutive days) or an intermittent (INT: 3 days/week for 3 weeks) heat acclimation protocol, comprising 30 min of exercise in hot conditions (WBGT 30°C). Increment...
Postmortem characterization of cranial nuchal bursa and ligament in healthy horses reveals subclinical gross and histopathologic abnormalities. To investigate the presence of subclinical cranial nuchal bursitis and characterize its histopathologic features and association with Borrelia burgdorferi. Unassigned: This was a prospective descriptive cadaver study on a convenience population of horses in a B burgdorferi-endemic region (15 horses: 5 geldings and 10 mares of various breeds; 4 to 29 years old). Horses without history or clinical signs of cranial nuchal bursitis underwent euthanasia and tissue donation. Cranial nuchal bursa, synovial fluid, and nuchal ligament were collected postmortem. The bursa and ligament were evaluated via...
Temporal variation in incretin and insulin secretion in ponies in association with dietary macronutrients. Equine insulin dysregulation (ID) is a common condition that predisposes to hyperinsulinaemia-associated laminitis. Improved pathophysiological understanding would enable better management of ID and reduce the risk of laminitis. The incretin peptides, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), augment the insulin response to dietary glucose and GLP-1 has been implicated in the pathophysiology of ID. However, their temporal variation in response to a low-energy diet has not been reported. This study determined the variation in GLP-1, GIP and insulin ...
Screening of Y-chromosomal STR loci and development of a multiplex PCR system for paternal lineage identification in horses. With growing demand for pedigree verification and breed management in horses (Equus caballus), reliable paternal lineage tools are essential. Y-chromosomal STRs (Y-STRs) have advantages over autosomal STRs due to paternal inheritance and lack of recombination. However, few validated loci and no standardised efficient genotyping systems limit their use. Current methods often require multiple reactions, increasing cost and labour. Thus, identifying informative Y-STR loci and developing a multiplex PCR system for cost-effective paternal lineage analysis is urgently needed. Objective: To identify ...
Photodynamic therapy with infracyanine green induces keratocyte depopulation in the normal equine cornea. Use of photodynamic therapy (PDT) for the treatment of immune-mediated keratitis (IMMK) in horses is becoming common. The safety and morphologic impact on the normal equine cornea have not been investigated, and the mechanism of its efficacy is unknown. Objective: To investigate the morphologic effects and safety of in vivo PDT on healthy equine corneas. Methods: In vivo experiment. Methods: Six university-owned horses underwent unilateral corneal PDT with intrastromal infracyanine green (EmunDo®) and photoactivation with an 810 nm diode laser (500 mW for 2.5 min = 75 Joules). Compl...
Assessment of Blood Profiles and Pain in Sport Horses Undergoing Intrarectal Ozone Therapy. Medical ozone is used in various treatments due to its oxidising properties. Objective: We aimed in this study to evaluate the impact of intrarectal ozone therapy on haematological and biochemical parameters, as well as the pain induced by the procedure in sport horses. Methods: In vivo experiment with 12 Quarter Horses (3 males and 9 females) used as their own controls to assess the effects of ozone therapy. Methods: Blood samples were collected before treatment (Control), 24 h after ozone therapy (24 h post-treatment), and 7 days after the last day of ozone therapy (7 days post-treatment). ...
Characterization of isolated late preantral and early antral equine ovarian follicles. Understanding how to effectively isolate a large number of healthy follicles is essential for increasing success rates in ARTs, such as in vitro culture and cryopreservation. Late secondary (preantral) and early tertiary (antral) follicles isolated from the intermediary portion of equine ovarian tissue sliced at two different thicknesses (0.25 mm vs. 0.50 mm) were characterized according to regional distribution (dorsal, medial, and ventral), morphofunctional features, and epigenetic profiles. After isolation via microdissection, follicles were evaluated for membrane integrity (trypan blue), v...
A randomized, masked, crossover, clinical trial of the efficacy and safety of nebulized albuterol sulfate and dexamethasone sodium phosphate in asthmatic horses. Nebulization of injectable dexamethasone sodium phosphate (DSP; 0.01 mg/kg) to horses with severe equine asthma (SEA) was previously found to be ineffective. Horses with SEA have marked bronchoconstriction that decreases peripheral lung deposition of nebulized drugs. Administration of a bronchodilator immediately before nebulizing dexamethasone may improve efficacy. Objective: Evaluate the therapeutic effects and optimal dose of nebulized DSP after nebulized albuterol in horses with SEA. Methods: Seven horses with SEA from a research herd. Methods: In this masked randomized crossover trial, h...
Equine autologous platelet concentrate is a leukocyte-rich platelet-rich plasma with a high interleukin-1Ra-to-interleukin-1β ratio and high transforming growth factor-β1 concentration. To quantify platelets, leukocytes, cytokines, and growth factors in ProVet autologous platelet concentrate (APC). We hypothesized that APC would contain significantly increased leukocytes and platelets compared to whole blood and significantly increased concentrations of anti-inflammatory cytokines and growth factors compared to serum. Unassigned: Blood was obtained from 6 horses and processed to produce APC. Leukocyte and platelet concentrations were quantified in whole blood and APC. Cytokines, including interleukin (IL)-1β, IL-4, IL-6, IL-10, tumor necrosis factor-α, and IL-1Ra, and growt...
QT interval and cardiac restitution dynamics in racehorses: Observations during maximal effort. Sudden cardiac death is a leading cause of athletic death in both humans and horses, making racehorses a potentially valuable model for investigating sudden cardiac death. Cardiac restitution ratio (QT/TQ interval) is used to assess arrhythmia risk in humans, but investigations in athletes are scarce. The objective was to characterize QT interval and cardiac restitution ratio in Thoroughbred racehorses during maximal effort. Automated restitution analysis was performed using 2709 pairs of cardiac cycles from 30 Thoroughbred horses during races. Cardiac cycles were obtained during: pre-race; ac...
Long term safety and efficacy of a functionalized nanogel with endothelin-1 and bradykinin receptor antagonist peptides for treatment of osteoarthritis of the metacarpophalangeal and distal interphalangeal joints in horses: a descriptive clinical pilot study. Intra-articular drug delivery systems (DDS) are emerging as promising therapies for osteoarthritis (OA), yet their efficacy in spontaneous clinical cases remains largely untested. This uncontrolled, descriptive pilot study was designed to provide a proof of concept for the feasibility, safety, and preliminary clinical effects of intra-articular administration in sport horses with naturally occurring OA. The study involved a peptide-functionalized nanogel composed of chitosan and hyaluronic acid, delivering endothelin type A (BQ-123) and bradykinin B1 (R-954) receptor antagonists, which have pr...
Horse immune response of recombinant Lawsonia intracellularis vaccine: Assessing the immunomodulatory impact of probiotic supplementation. Equine proliferative enteropathy (EPE), caused by Lawsonia intracellularis induces intestinal epithelial hyperplasia, resulting in malabsorption, weight loss, colic, and diarrhea. Despite its clinical and economic importance, no equine-specific vaccine is commercially available. Recombinant subunit vaccines are a safe and scalable alternative; however, their immunogenicity often requires improvement. Probiotic supplementation with Bacillus toyonensis may act as an immunomodulatory strategy to potentiate vaccine efficacy. This study aimed to evaluate the immunogenicity of a recombinant protein ...
Systematic review and meta-analysis of adult multipotent stromal/stem cell treatment for equine tendinopathy and desmopathy. Over the last few decades, cell and cell-based therapies emerged as treatment options for equine tendinopathy and desmopathy. The objective of this study was to critically evaluate outcomes following treatment of equine tendinopathy or desmopathy with adult multipotent stromal/stem cells (MSCs). Unassigned: The PubMed and Web of Science databases were searched for "equine/horse," "tendon/tendinopathy/tendonitis/ligament/ligamentopathy/desmopathy/desmitis," "stem/stromal/mesenchymal/multipotent," and "cell" from January 2001 to June 2025. Studies were identified according to PRISMA guidelines, ...
Prolonged wireless measurement of intragastric pH in foals. The pathogenesis of gastric ulceration is not well understood in foals, and its relationship with gastric acidity requires further investigation. A wireless capsule, designed for intraesophageal pH monitoring in humans, was adapted to measure intragastric pH in adult horses. Objective: To (1) determine the feasibility of wireless intragastric pH measurement in foals; (2) determine capsule attachment duration; and (3) describe the intragastric pH profiles recorded. Methods: Eight healthy foals aged 24-98 days. Methods: Prospective interventional study. Capsules were attached to the glandular g...
Pharmacokinetic analysis and steady-state predictions of different preparations of metronidazole administered per rectum in adult horses. Manipulation of forms of rectally administered metronidazole to improve bioavailability in horses has not been reported. Objective: Evaluate the pharmacokinetics of 3 rectal metronidazole preparations compared to nasogastric (NG) administration. Methods: Seven healthy horses. Methods: Phase 1A was a randomized, 3-way crossover, single-dose pharmacokinetic study, and Phases 1B and 2 were non-randomized, single-dose follow-up studies. Metronidazole (20 mg/kg) was administered NG and rectally in water (RW20), as a rectal gel (RG), and in dimethyl sulfoxide (DMSO). Metronidazole (80 mg/kg) was a...
The effects of furosemide on pulmonary transmural pressure and exercise-induced pulmonary hemorrhage in supramaximally exercising thoroughbred racehorses. Maximal intensity exercise in equine athletes induces pulmonary capillary stress failure and exercise-induced pulmonary hemorrhage (EIPH) secondary to excessive transmural pressure (Ptm). Furosemide decreases EIPH severity and pulmonary arterial (PAP) and pulmonary wedge (PAW) pressures. Objective: Assess the effects of furosemide on Ptm and EIPH during supramaximal exercise. Methods: Six fit retired Thoroughbreds with consistent EIPH Grade ≥ 2. Methods: Horses performed a controlled crossover design protocol, completing standardized treadmill tests (120%V̇O2max) before and 4 h after int...
Vectorcardiography at rest and during exercise in horses using the Delta (Δ) 12-lead configuration. Twelve-lead electrocardiography (ECG) is essential in human cardiology but remains poorly investigated in equine medicine due to a lack of standardization and inconsistent findings. Objective: Describe the normal vectorcardiogram (VCG) variation in horses at rest and during exercise using Delta 12-lead ECG, including repeatability and intra- and interobserver variations. Methods: One hundred two healthy Warmblood horses, aged 3-20 years, were examined at rest, of which 30 also during exercise. Methods: Prospective, observational study. Electrocardiograms were recorded using a Δ 12-lead confi...
An in-hospital clinical trial assessing nebulized lidocaine compared to saline for treatment of asthma in horses. Corticosteroids are the main pharmacologic treatment for equine asthma (EA) but may have adverse effects in metabolically unstable horses. Recent pilot studies support the use of nebulized lidocaine as an alternative treatment option. Objective: Nebulized lidocaine will improve EA-associated clinical variables and airway inflammation. Methods: Twenty client-owned horses diagnosed with EA. Methods: Randomized, blinded, in-hospital study comparing 1 mg/kg preservative-free 4% lidocaine (n = 10) nebulized via Flexineb (twice daily for 7 doses) to 0.9% saline control (n = 10). Clinical examin...
Pharmacokinetics of Topical Administration of Altrenogest in Mares and Implications for Human Health. Altrenogest is a synthetic progestogen widely used in equine reproductive management. Adverse effects to altrenogest have been reported in people with cutaneous exposure reported as the highest exposure pathway. Despite these reports, there has been no quantitative research to determine the capacity for altrenogest to be absorbed through skin. This study aimed to determine if cutaneous application of oral altrenogest results in systemic absorption in mares and to evaluate the influence of application site. A randomized, two-period, two-treatment crossover study was undertaken in eight mares. M...
Isolation and characterization of seminal extracellular vesicles subsets and their impact on sperm freezability in stallions. The ability of spermatozoa to withstand cryopreservation differs between stallions. While the underlying mechanisms of these differences are not fully understood, seminal plasma (SP) may play a crucial role in modulating sperm cryotolerance. Seminal plasma contains a heterogeneous population of extracellular vesicles (sEVs), nanometer-sized membrane particles that can transfer biomolecules to sperm modulating their function. This study aimed to isolate and characterize two sized-sEV subsets-small (S-) and large (L-)-from stallion SP, and to evaluate their involvement in sperm freezability. Sem...
Natural eggshell membrane supplementation for chronic lameness in warmblood horses: a 12-week prospective before-after study. Osteoarthritis is a leading cause of equine lameness, yet pragmatic evidence for nutraceuticals in horses remains limited. Unassigned: We prospectively evaluated 12 weeks of daily natural eggshell membrane (NEM; 12 mg/kg, orally) supplementation in Warmblood horses with chronic lameness using a single-arm before-after design. Ten horses were enrolled and prespecified paired contrasts compared visit 3 (V3, week 12) with baseline (V1). Outcomes included rider-reported under-saddle function (walk and trot), examiner-graded lameness (rest and walk-trot composite), simple joint-angle kinematics...
Equine lameness detection and monitoring during diagnostic anaesthesia with an instrumented hoof boot. Ground reaction forces are accepted as gold standard for objective assessment of weightbearing lameness but measurements at the hoof are limited to experimental devices. This study aimed to evaluate whether innovative instrumented hoof boots (IHBs) could detect and monitor lameness in horses during diagnostic anaesthesia. Twenty-six horses referred for lameness examination (15 front limbs, 17 hindlimbs) were equipped with IHBs and body mounted inertial sensors. Data were collected simultaneously before and after diagnostic anaesthesia until objectively considered positive. Recorded IHB data i...
A topographic analysis of skin thickness in horses. A systematic study of regional skin thickness in different types of horses has not yet been described. Knowledge about regional skin thickness has long been used in human medicine to optimise wound care and skin grafting outcomes and similar knowledge could prove useful in equine wound management. The objective of the current study was to report the topographical variation in skin thickness of Warmblood (WB) and Coldblood (CB) type horses and to compare different methods for measuring skin thickness. Horses free of skin conditions and euthanised for reasons unrelated to this study were include...
Ultrasonography accurately detects equine cervical articular process joint effusion with comparable performance to computed tomography. To compare effusion scores obtained via ultrasound (US) and computed tomography (CT) in equine cervical articular process joints (CAPJs). Unassigned: Cadaveric cervical specimens (skull through C7) from 6 horses were used. One specimen was used to establish maximal joint distension volume. In the main study phase, 50 CAPJs were randomly assigned to receive 0, 2, or 4 mL of positive contrast solution. The CAPJs were imaged via US and CT before and after injection. Effusion was subjectively graded on a scale of 0 to 4 for both modalities. Statistical analyses compared pre- and post-injection eff...
The high fundamental frequency in horse whinnies is generated by an aerodynamic whistle. Understanding why the frequencies of some species' vocalizations are far above or below those predicted by body size is key for explaining the remarkable diversity of mammalian vocal behavior. Horses, among the largest terrestrial mammals, provide a clear example of such deviation: their whinnies contain a very high fundamental frequency (>1,000 Hz) in addition to a second, lower one (∼200 Hz). While the lower fundamental frequency of whinnies is readily attributed to vocal fold (laryngeal) vibrations, the biomechanical processes underlying the production of the higher one remain unknown. Us...
Equine Corneal Stromal Invasive Squamous Cell Carcinoma: Clinical and in Vivo Confocal Microscopic Features of 7 Cases. To describe the clinical and in vivo confocal microscopy (IVCM) characteristics of horses with corneal stromal invasive squamous cell carcinoma (CSI-SCC). Methods: Retrospective study of 7 horses with histopathologically confirmed unilateral CSI-SCC. Methods: Horses with corneal CSI-SCC were examined by laser scanning IVCM. Signalment, clinical findings, and histopathology results were compared with IVCM findings. Results: Clinical ocular lesions in all horses included a heavily vascularized, opaque, gray or tan, anterior or midstromal opacity invading the cornea from the limbus. The corneal ...
Antibiofilm and resistance-modulating properties of tt-farnesol against Streptococcus equi subsp. equi and zooepidemicus. The aim of this study was to investigate the antibacterial, antibiofilm and modulating activities of trans-trans-farnesol (tt-farnesol) on two strains of Streptococcus equi subsp. equi and two strains of S. equi subsp. zooepidemicus, pathogenic or commensal bacteria of horses. Tt-farnesol showed bactericidal activity against all tested strains, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) between 8 and 4 μg/mL. The sesquiterpene caused significant damage to the bacterial membrane, and its antibacterial activity did not appear to depend on oxidat...
Vaccination-associated lameness in warmblood horses after intramuscular injection. Intramuscular vaccination is a routine component of equine medicine, but local muscle soreness may transiently affect gait symmetry. Objective data on vaccination-associated gait changes in horses are lacking. Objective: To investigate whether intramuscular vaccination induces measurable gait asymmetries depending on injection site, to inform recommendations on vaccination site selection and short-term exercise management. Methods: In this prospective, randomised, blinded, placebo-controlled study, eighteen clinically sound Warmblood horses were enrolled and received an intramuscular vaccinati...