Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
To document morphologic changes that occur in equine intestinal serosa after experimentally induced ischemia and subsequent reperfusion (jejunum, ascending colon) or after intraluminal distention and decompression (jejunum). Methods: Morphologic effects of ischemia-reperfusion or intraluminal distention-decompression determined on the serosal layer of the equine jejunum. The large colon serosa was evaluated after ischemia-reperfusion injury. Methods: Seven adult horses. Methods: After induction of general anesthesia and ventral median celiotomy, ischemia was created by arteriovenous (AVO) and ...
This Opinion piece is offered as a cursory overview of sperm development, function, and transport through the eyes of an equine veterinarian. My professional background is predominantly clinical in nature, but my fascination with sperm function and preservation has led to a fairly sizeable review of the scientific literature over the years in hopes of extracting laboratory findings that have application to my daily activities in the clinical arena. Spermatozoa are quite unique among cellular types with regard to both form and function, and represent the only endogenously derived cell type that...
This article provides an overview of initial assessment and management of common emergency presentations in donkeys and mules. The principles are similar to those in horses (and ponies), but clinicians must be aware of differences in recognition of signs of pain/disease, approach to handling, pharmacology of some drugs, and subtle differences in the physiology and local anatomy in donkeys and mules. The epidemiology of common disease presentations will vary between pet/companion or working/farmed donkeys and mules. Regular dental checks, deworming, vaccination, and monitoring of behavior and q...
Fifteen horses harboring naturally acquired, patent Parascaris equorum and Oxyuris equi infections were equally allotted to 3 treatment groups given (1) injectable vehicle; (2) injectable ivermectin at the dose rate of 200 microgram/kg of body weight; and (3) injectable ivermectin at the rate of 300 microgram/kg. All treatments were given IM in the neck. All animals were killed 14 days after treatment and examined for the targeted nematodes. Regardless of dose rate, ivermectin proved 100% effective in the removal of adult O equi and P equorum infections. Levels of immature P equorum were decre...
This study was designed to investigate whether horses with clinical signs of back pain due to suspected soft tissue injuries were affected by polysaccharide storage myopathy (PSSM). Diagnosis of PSSM in muscle biopsies obtained from the M. longissimus lumborum of 5 showjumpers and 4 dressage horses with a history of back pain is reported. M. longissimus lumborum biopsies of these horses were characterised histopathologically and in 3/9 cases also by electron microscopy. Observations were compared with M. gluteus biopsies of the same horses, and with M. gluteus biopsies obtained from 6 Standard...
A 4-month-old Thoroughbred filly presented for abdominal pain was diagnosed with a T-shaped malformation of the ventral colon at exploratory laparotomy. Following resection and anastomosis of the large colon, no further episodes of abdominal pain occurred during a 12-month follow-up. Acute dehiscence of the linea alba occurred as a complication of the initial laparotomy, but was successfully managed following additional surgical repair. T-shaped malformation of the ventral colon has not previously been reported and is considered a congenital malformation of mesocolon formation.
Vesicular stomatitis is an infrequent yet important vesicular disease of cattle, horses, and swine. Periodic outbreaks of this disease in the United States have caused economic losses in cattle herds because of decreased production, movement restrictions, and trade embargoes. Vesicular stomatitis causes clinical signs indistinguishable from those of foot-and-mouth disease. It is of utmost importance that appropriate samples are collected from clinical cases of vesicular disease in cattle and swine so a rapid laboratory diagnosis can be made.
The objective of this study was to compare effects of butorphanol (BUT) or buprenorphine (BUP), in combination with detomidine and diazepam, on the sedation quality, surgical conditions, and postoperative pain control after cheek tooth extraction in horses, randomly allocated to 2 treatment groups (BUT: = 20; BUP: = 20). A bolus of detomidine (15 μg/kg, IV) was followed by either BUP (7.5 μg/kg, IV) or BUT (0.05 mg/kg, IV). After 20 min, diazepam (0.01 mg/kg, IV) was administered and sedation was maintained with a detomidine IV infusion (20 μg/kg/h), with rate adjusted based on scores to ...
Anoplocephala sp. parasites are among the most frequent tapeworms in equines and are associated with intestinal infections. This survey had the objective to verify Anoplocephala sp. prevalence at Sociedade Hípica Paranaense (SHPr). The animals were treated with ivermectin, which does not have efficacy against Anoplocephala sp.. To determine whether eggs of Anoplocephala sp. were present, a modified centrifugal flotation technique was used and also eggs per gram of faeces (EPG). None of the samples showed Anoplocephala sp. eggs and only 11% of the animals had positive values for EPG. The resul...
Equine recurrent uveitis serves as a spontaneous model for human autoimmune uveitis. Unpredictable relapses and ongoing inflammation in the eyes of diseased horses as well as in humans lead to destruction of the retina and finally result in blindness. However, the molecular mechanisms leading to inflammation and retinal degeneration are not well understood. An initial screening for differentially regulated proteins in sera of uveitic cases compared to healthy controls revealed an increase of the alternative pathway complement component factor B in ERU cases. To determine the activation status ...
The upper respiratory tract is a frequent cause of exercise intolerance in horses, particularly in racing horses. There are a myriad of laryngeal abnormalities that may restrict airflow at the rima glottidis. Careful endoscopic examination is a crucial part of the examination of any racing horse suffering from poor performance. There has recently been interest in spectrum analysis of respiratory sounds. It has been determined that laryngeal hemiplegia and dorsal displacement of the soft palate have unique sound patterns. Therefore, spectrum analysis of respiratory sounds may prove to be useful...
Two closed horse herds (Old Lot 4 and Field 24), infected since 1966 with Population B small strongyles resistant to thiabendazole (TBZ) and phenothiazine (PTZ), were terminated in February, March, and May, 2005. At necropsy, only the large endoparasites were identified and counted. The number of horses on pasture was 14 (239 days of age to 23 years old) for Old Lot 4 and two (3 to 20 years old) for Field 24. The time of the last antiparasitic treatment, relative to the year (2005) of necropsy, was 26 years for Old Lot 4 and 9 years for Field 24 horses. Gasterophilus intestinalis third instars...
A breed known for its versatility, the American Quarter Horse (QH), is increasingly bred for performance in specific disciplines. The impact of selective breeding on the diversity and structure of the QH breed was evaluated using pedigree analysis and genome-wide SNP data from horses representing 6 performance groups (halter, western pleasure, reining, working cow, cutting, and racing). Genotype data (36 037 single nucleotide polymorphisms [SNPs]) from 36 Thoroughbreds were also evaluated with those from the 132 performing QHs to evaluate the Thoroughbred's influence on QH diversity. Results s...
To determine risk factors for Clostridium piliforme infection in neonatal foals on a Thoroughbred breeding farm in California. Methods: Case-control and retrospective cohort studies. Methods: 322 neonatal Thoroughbred foals either born on the study farm or born elsewhere but traveled to the farm with their dam during the 1998, 1999, and 2000 breeding seasons. Methods: Mare and foal records from 1998, 1999, and 2000 were examined, using case-control design methods to determine variables associated with increased risk of C. piliforme infection in foals. Important risk factors identified in the c...
Four horses were evaluated because of hind limb lameness. Two had a distinct gait abnormality at the walk characterized by lateral rotation of the point of the calcaneus and medial rotation of the toe during the stance phase. Nuclear scintigraphy revealed a focal area of intense radioisotope uptake in the caudodistal aspect of the femur in all 4 horses, and 3 of the horses had a corresponding proliferative reaction on the caudodistal cortex of the femur on radiographs. In all 4 horses, a diagnosis of injury to the origin of the gastrocnemius muscle was made. Three of the horses returned to ath...
Serum anti-Müllerian hormone (AMH), a marker of equine cryptorchidism, is detectable in intact and cryptorchid stallions but not in geldings because it is secreted from Sertoli cells. A 4-year-old uncastrated Thoroughbred racehorse had no visible testes; therefore, the horse was considered a bilateral cryptorchidism. However, the serum AMH was undetectable (<0.08 ng/ml). Human chorionic gonadotrophin (hCG) stimulating test result indicated that the horse was a gelding. The results of sex chromosomal analysis and sequence analysis of SRY gene suggested that the horse was a genetically-intac...
The research article describes the treatment, recovery process, and prognosis of a 2-month old Quarter Horse, who suffered from severe lameness in the left forelimb due to an avulsion-type fracture […]
A clinical evaluation of a new, purified, heat-treated equine rabies immunoglobulin (PHT-Erig), F(ab')2 preparation, was carried out in Thailand and in the Philippines-two countries where rabies is endemic. An initial prospective, randomised, controlled trial (Study 1), compared the safety and pharmacokinetics (serum concentrations of rabies antibodies) after administration either of PHT-Erig or of a commercially-available, equine rabies immune globulin (Erig PMC). A second trial (Study 2) simulated post-exposure rabies prophylaxis by using a reference cell culture vaccine, the purified Vero-c...
The objective of this study was to graft autologous mesenchymal stem cells (MSCs) at the site of surgical repair of a soft palate defect in an adult horse in an attempt to improve wound healing and to investigate whether the transplanted MSCs would integrate into the soft palate structure and participate in regeneration. Bone marrow was collected from an adult horse with a full-thickness soft palate defect. The MSCs were isolated, cultured in monolayers, and labeled with 5-bromo-2-desoxymidine (BrdU) and chloromethylbenzamido-DiI-derived (cm-DiI) before transplantation. The soft palate defect ...
A review of the literature is given concerning the anatomy and pathophysiology of the equine penis with regard to priapism: a prolonged erection of the penis not associated with sexual arousal. Several treatment options, such as flushing of the corpus cavernosum penis with heparinized saline and the creation of shunt between the corpus cavernosum penis and the corpus spongiosum penis are discussed. Subsequently, a case of priapism in a stallion following the injection of acepromazine, is discussed. The priapism resolved after the corpus cavernosum penis was flushed with the stallion under gene...
Exertional rhabdomyolysis (ER) and its familial basis in Warmblood horses is incompletely understood. Objective: To describe the case details, clinical signs and management of ER-affected Warmblood horses from a family with a high prevalence of ER, to determine if histopathological signs of polysaccharide storage myopathy (PSSM) and the glycogen synthase (GYS1) mutation are associated with ER in this family, and to investigate potential risk factors for development of ER. Methods: A family consisting of a sire with ER and 71 of his descendants was investigated. History of episodes of ER, husba...
Unlike in Warmblood horses, aortic rupture is quite common in Friesian horses, in which a hereditary trait is suspected. The aortic connective tissue in affected Friesians shows histological changes such as medial necrosis, elastic fibre fragmentation, mucoid material accumulation and fibrosis with aberrant collagen morphology. However, ultrastructural examination of the collagen fibres of the mid-thoracic aorta has been inconclusive in further elucidating the pathogenesis of the disease. Objective: To assess several extracellular matrix (ECM) components biochemically in order to explore a pos...
To determine the causes of horse-related injuries in a rural western community. Methods: Prospective identification of persons with horse-related injuries and retrospective interviews with patients or witnesses to determine causes. Methods: A small rural community in Alberta where the western style of riding predominates. Methods: All patients presenting to two family medicine clinics or to the Sundre General Hospital emergency department. Methods: Factors contributing to the injury as recalled by patients or witnesses, and characteristics of the persons, horses, and injuries. Results: Two thi...
Splan RK, Noel FI, Gardner GM, Kenny LB.Proper pasture management improves forage yield, reduces costs, and minimizes environmental impacts, but may be difficult in suburban settings. Objective: This study evaluated pasture condition and management practices on 28 horse farms in counties adjacent to the Philadelphia metropolitan area. Methods: Between November 2019 and January 2020, 72 pastures (2-3/farm) were assessed via soil sampling, USDA-NRCS Pasture Condition Score Sheet (PCSS), Penn State Equine Pasture Evaluation Disc (EPED), and farm manager interviews. Linear models assessed effects of management factors on pasture conditi...
Of the mycotoxicoses caused by molds contaminating grains or their byproducts, leukoencephalomalacia of horses and less frequently aflatoxicosis in cattle have been reported in South America. However, the most important group of mycotoxins in the region are those caused by fungi that infect forages and other types of plants and have regional distribution. In this group, ergotism is important, both caused by Claviceps purpurea infecting grains or by Epichloë coenophiala infecting Schedonorus arundinaceus. Other important mycotoxicoses are those caused by indole-diterpenes produced by Clavicipi...
Ma Y, Zhang J, Li X, Zhao H, Lu W, Li H, Yang K.Anthelmintic treatment is widely used in equine health management to control parasitic infections; however, its potential effects on the gut microbiota and metabolic characteristics remain poorly understood. In this study, twelve Yili horses were randomly assigned to two groups: a control group (C), which received no anthelmintic treatment, and a Miechongshu-treated group (T), which was orally administered Miechongshu at a dose of 0.36 g/kg body weight on day 0. Fecal samples were collected from the rectums of Yili horses on day 14 after administration, and differences in gut microbial composi...
Young PL, Hyde R, Douglas J, Freeman SL.Artificial Intelligence (AI) is being increasingly used for equid health and welfare. This study aimed to establish consensus on where and how AI should be developed to achieve maximum benefit in this field. A workshop involving 41 stakeholders generated statements about current welfare concerns, areas for AI development, and barriers and solutions to AI use. Statements were circulated through Delphi surveys (acceptance set at 75% agreement). One-hundred-and-six statements reached agreement. Ethological needs not being met and poor equid management practices were key welfare concerns. Particip...
Siwińska N, Żak-Bochenek A, Jawor P, Pietrzak A, Kutermak O, Słowikowska-Łoś M, Kaczmarek B.Due to growing interest in endocrine diseases, more studies aim to interpret the baseline concentrations and reference intervals of hormone values like adrenocorticotropic hormone (ACTH) and thyroxine (T4) in horses. Most studies available in the literature focus on evaluating ACTH and thyroid hormone values in adult and geriatric horses, with only a few considering younger donkeys and ponies. This study aimed to measure ACTH and T4 in autumn and spring in younger equids. The study included 42 young equids, which were divided into three groups: horses, ponies, and donkeys. The concentration of...
Arora S, Kieson E, Rudd C, Gloor PA.Automated recognition of equine-human interaction behaviors from video represents a significant challenge in computational ethology, with critical applications spanning animal welfare assessment, equine-assisted services evaluation, and safety monitoring in equestrian environments. Existing approaches to animal behavior recognition typically focus on single species in isolation, rely solely on facial expression analysis while ignoring full-body posture, or employ flat classification architectures that fail under the severe class imbalances characteristic of naturalistic behavioral datasets. Fu...
Kodama S, Mita H, Tamura N, Koyama D, Matsukawa M.Bone diagnosis using x-ray techniques, such as computed tomography and dual-energy x-ray absorptiometry, can evaluate bone mineral density (BMD) and microstructure but does not provide elastic properties. This study investigated the ultrasonic properties of racehorse leg cortical bone, focusing on the relationship between wave velocity, BMD, and hydroxyapatite (HAp) crystallite alignment. The results showed a strong correlation between wave velocity and BMD, suggesting that quantitative ultrasound-obtained wave velocity is primarily influenced by BMD, followed by the HAp alignment direction.
Caceres AM, Sperandio LMS, Alvarenga NACA, Borges AS, Oliveira-Filho JP.Bull-catching (vaquejada) accounting for approximately 13% of sport horses in Brazil. Genetic screening has enabled strategies to reduce the spread of inherited disorders, including Hereditary Equine Regional Dermal Asthenia (HERDA), a major skin disease included in the Six Panel required for registration by the Brazilian Quarter Horse Breeders Association. Although the HERDA-associated variant has been extensively studied in other disciplines, it had not been evaluated in Bull-catching Quarter Horses (QH). Objective: The present study aimed to determine the allele frequency of the pathogenic ...
Hardwick JL, Ahern BJ, Anderson BH, Franklin SH.Concerns regarding the reliability and consistency of yearling sales endoscopy in Australia and New Zealand have led to reduced industry confidence. Recent studies have clarified the relationship between yearling laryngeal function (YLF) grades and future outcomes. Objective: To build expert consensus on the most appropriate method for grading YLF, assess the clinical relevance of each grade on future race performance and prosthetic laryngoplasty risk, and develop guidelines for pre-sale endoscopic technique. Methods: Modified Delphi study. Methods: Anonymous, iterative surveys were distribute...
Vanderbiest L, Rousseau L, Renaville B, Aleman M, Finno C, Milan A, Vinardell T.Occipitoatlantoaxial malformations (OAAM) are developmental disorders occurring at the occiput, atlas and axis. OAAM type 1 is a familial disorder affecting Arabian horses. Currently, a single genetic mutation in the HOXD3 gene region can be tested to confirm the diagnosis. This case describes a 3-year-old Arabian gelding affected with OAAM. Clinical examination revealed a proximal cervical deformation on the right side and severe stiffness of the neck in the sagittal plane without associated pain. Neurological examination demonstrated a generalized proprioceptive ataxia. Radiographs revealed ...
Ibrahim MA, Noshy MM, Mohamed HRH, Abd El-Gawad MEH.This study combined classical cytogenetics and ISSR molecular markers to characterize genetic diversity in 24 Egyptian Arabian horses. Karyotyping revealed the standard equine chromosome number (2n = 64) with no numerical or structural abnormalities. Chromosome measurements were consistent with ISCN Equine standards: autosomal relative lengths (RL%) followed the expected size hierarchy, biarmed chromosomes displayed metacentric to submetacentric morphology (CI = 37-50%), and recalculated centromeric indices confirmed the presence of measurable p-arms on all acrocentric chromosomes. ISSR an...
Orsini JA, Stefanovski D.This study evaluated the clinical application, outcomes, and prognostic indicators of deep digital flexor tenotomy (DDFT) in horses with chronic laminitis. Unassigned: A computer-generated search identified all possible cases of laminitis for horses referred to the George D. Widener Hospital for Large Animals at the University of Pennsylvania between 2010 and 2022. Medical records were reviewed for a diagnosis of laminitis by clinical examination and radiographs. The population was characterized by breed, age, clinical features, and radiographic findings. Poisson regression was performed to id...
Hallsten M, Fogle C, Shippy S, Hobbs KJ, Blikslager AT, Elane GL.To describe the sensitivity, specificity, predictive values, and accuracy of abdominal palpation per rectum in horses treated surgically for colic. Unassigned: Medical records were gathered over 5 years (2019 to 2024). Findings of abdominal palpation per rectum were collected and compared to surgical diagnosis, and cases were categorized as true or false positive and negative. Signalment, physical examination parameters, hematologic values, and years of examiner experience were recorded. Unassigned: Records of 453 horses were included. Overall sensitivity and positive predictive value were 86%...
Paranjape VV, Hopster K, Lutvikadic I, Driessen B.Intraoperative haemorrhage during equine anaesthesia is a rare but potentially fatal complication requiring prompt haemodynamic support. Postural manoeuvres such as Trendelenburg (TL) positioning and vasopressor support augment venous return and improve cardiac output (CO), yet their efficacy in anaesthetised hypovolemic horses remains unstudied. Objective: To evaluate haemodynamic effects of TL positioning during normovolemia and acute haemorrhagic hypovolemia, and to determine whether concurrent norepinephrine (NE) infusion enhances cardiovascular stabilisation. Methods: In vivo experiments....
Alonso-de-la-Varga ME, Lomillos Pérez JM.Draft and pulling horses are used in a traditional equestrian sport in the Valencian Community (Spain), in which horses must pull a cart loaded with a weight equivalent to twice their body weight along a sand track. Although it constitutes cultural heritage, this practice raises questions about animal welfare since it involves working horses under demanding physical exertion. There are no studies evaluating the welfare of horses participating in these draft and pulling competitions using validated clinical, ethological, and physiological indicators, and the present work aims to fill this knowl...
Faramarzi B, Lee D, Khamas W, Dong F.The distal sesamoidean impar ligament (DSIL) is a key component of the equine podotrochlear apparatus, yet its role in conditions such as caudal heel pain and navicular syndrome remains poorly understood. The objective of this study was to characterize the histological properties of the DSIL and evaluate how it is influenced by breed and age. Eighty-four cadaveric forelimb DSIL samples were collected from young, athletic Quarter horses (QHs), Thoroughbreds (TBs), and older, retired Quarter horses. Samples were stained and assessed for vessel size and count, number of nerve fascicles, and the r...
Navas de Solis C, Durando M, Nath L, Durward-Akhurst S.Exercise associated sudden death (EASD), defined as a fatal collapse in a closely monitored and previously presumed clinically healthy horse that occurs during exercise or within approximately 1 h after exercise, is disproportionately more common in equine than in human athletes. Objective: To describe ECGs from EASD cases in Thoroughbred racehorses. Methods: Retrospective case series. Methods: An international call for potential cases was made through direct contact with relevant racing authorities requesting that trainers of horses which had experienced EASD consent to researchers gaining ac...
Bini de Lima AC, Sebastião da Fé VC, Palermo Hernandes MS, Pfeifer de Cristo EC, Dos Santos Fagundes Euzébio AG, E Silva Sousa MV....This study aimed to evaluate the ability of social noncontact environmental enrichment to facilitate social buffering and to characterize the emotional experience of horses subjected to restraint in stock by assessing physiological parameters and facial expressions. Pantaneiro horses (n = 11) were evaluated in a crossover design with two treatments: social noncontact enrichment during stock restraint and social isolation during stock restraint. Physiological parameters (heart rate, heart rate variability, respiratory rate, ocular temperature by infrared thermography, and auricular temperat...
Outouil M, Daugherity EK, Warnick LD, Perry PJ.Single-stall housing is a common system used for horses in various settings, including racing stables, riding schools, teaching and research facilities. Adequate stall space is necessary for horses to lie down and make postural adjustments, both of which are essential for equine rest and welfare. The Guide for the Care and Use of Laboratory Animals recommends a stall size of 144 ft2. However, not all stalls meet this size requirement, and there is limited literature supporting its use in terms of animal welfare. This study used a crossover design to compare behavioral and physiologic variables...
Whitfield-Cargile C, Coleman M, Hart K, Gomes D, Berghaus L, Duberstein KJ, Ellis K, Tinkle A, Shirzad R.Insulin dysregulation (ID) is common and diminishes welfare of horses. Current management relies on diet and exercise, with variable responses and limited medical options. Alpha-glucosidase inhibitors (AGIs) might provide adjunctive therapy. Objective: To evaluate the tolerance and effects of Reducose®, a Morus alba leaf extract standardized to 5% 1-deoxynojirimycin (DNJ), in healthy horses and horses at risk of ID. We hypothesized DNJ would be well-tolerated and reduce insulin responses to oral sugar tests (OSTs). Methods: Twenty-seven horses: 6 healthy (Phase I), 5 at risk for ID (Phase II)...
Kareskoski AM.Behavioral issues, such as persistent or strong estrus, non-specific pain, and performance challenges in mares are frequently attributed to the estrous cycle. Objective: The objectives of this study were to analyze retrospective data on mares presented for estrus-related behavioral complaints, and to propose a structured diagnostic framework for categorizing cases during work-up at different levels of care. Methods: A retrospective study was conducted using patient records of a total of 14993 mares. Results: In this data set, behavioral problems, pain, or poor performance were not repeatably v...
Camargo CE, Kozicki LE, Souza FA, de Lima PHL, Nogueira E.Nutritional strategies may modulate ovarian function and embryo recovery in donor mares, but field evidence for long-term multinutrient supplementation remains limited. Objective: To determine whether long-term micronutrient and amino acid supplementation increases embryo recovery per flush and ovarian responsiveness in donor mares. Methods: A total of 115 uterine flushes were performed under a crossover design across two consecutive breeding seasons in 12 multiparous, non-lactating crossbred donor mares (4-12 years). Mares received a basal diet or the same diet plus 40 g/day of a multinutrien...
Gallacher K, Woolford L, Gilbert RO, Santos LC, McLeod J, Hebart M, Agne GF, du Preez S, Kind KL.Assessment of the endometrium is an essential component of a breeding soundness examination in mares. The current reference standard for evaluating equine endometrial health is histopathological assessment of an endometrial biopsy, however, inconsistencies may arise when a single blinded biopsy is used. Confocal laser endomicroscopy (CLE) is non-invasive and enables real-time in-vivo imaging of the endometrium across multiple locations within the uterine lumen. An initial study revealed variation in CLE image quality between mares. Objective: This study aimed to compare the quality of endometr...
