Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
To evaluate the effect of four recumbent body positions on intraocular pressure (IOP) in anesthetized normal horses. Methods: Ten nonglaucomatous adult horses. Methods: Intraocular pressure was measured with a rebound tonometer in both eyes of standing sedated horses (baseline), then under general anesthesia during four randomized recumbent body positions, including Trendelenburg (Tr; 15-degree head down), reverse Trendelenburg (RTr; 15-degree head up), dorsal, and lateral; only the superior eye was measured in lateral positions. The mean of 3 IOP readings was taken at each position, allowing ...
There is a paucity of information regarding the association between common disorders and outcome over time in a large population of ill equine neonates. Objective: To describe the relative frequency of neonatal disorders in a large population of foals admitted to a neonatal intensive care unit, to determine the disorders and factors associated with nonsurvival and determine if the outcome of ill neonatal foals has improved over time. Methods: Retrospective study. Methods: Cases were selected from equine neonatal (≤14 days of age) admissions between 1982 and 2008. Multivariable logistic regre...
To compare ocular structures of Quarter Horses homozygous for hereditary equine regional dermal asthenia (HERDA) with those of Quarter Horses not affected by HERDA (control horses) and to determine the frequency of new corneal ulcers for horses with and without HERDA during a 4-year period. Methods: Cohort study of ocular structures and retrospective case series of horses with and without HERDA. Methods: The cohort portion of the study involved 10 Quarter Horses with HERDA and 10 Quarter Horses without HERDA; the retrospective case series involved 28 horses with HERDA and 291 horses without HE...
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...
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...
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...
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 ...
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...
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...
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.
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...
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...
is one of the most pathogenic nematodes affecting equids. Larval migration through the cranial mesenteric artery (CMA) with attendant arteritis and thromboembolism can result in fatal non-strangulating intestinal infarction. Once considered a historical disease, recent studies have described the reemergence of this pathogen in several European countries; however, little is known of the current prevalence of in the Canadian horse population. Unassigned: To determine the prevalence of active cranial mesenteric arteritis in horses submitted for postmortem examination to the Diagnostic Services...
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...
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...
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...
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...
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 ...
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.
Christofi E, Hoopes J, El-Hage C, Coffin J, Riley T, Cumming B.Since their arrival in the 1700s, horses have played a significant role in shaping the identity of rural and remote communities. However, Indigenous perspectives on the historical role of horses in communities have been largely underrepresented. In remote regions, where access to veterinary and medical services is limited, interactions between people and free-roaming horses present a potential risk for zoonotic disease transmission. This review identifies potential pathways for the transmission of equine zoonoses in rural and remote Aboriginal and Torres Strait Islander communities, aiming to ...
Leduc L, St-Jean G, Lavoie JP.Antimicrobials are commonly prescribed for the treatment of equine asthma, despite limited evidence supporting their use. Tracheal wash (TW) bacterial culture results are known to influence antimicrobial prescription decisions. Objective: To determine whether a positive TW bacterial culture in horses with asthma is associated with bronchial infection or colonisation, increased bronchial remodelling and airway inflammation by evaluating the presence of bacteria and airway remodelling in endobronchial biopsies, as well as bronchoalveolar lavage fluid (BALF) cytology and tracheal mucus scores. Me...
Hananeh W, Al Rukibat R, Hammad H, Mukbel R.Leishmaniosis is an endemic parasitic infection in Jordan and the Middle East. Despite the endemicity of leishmaniosis in Jordan and frequently reported humancases, no singleclinical case has been documented in animals throughout the country. This report documents the first two animal Leishmania cases in two different animal species with a current literature review. Cutaneous leishmaniosis was diagnosed in an adult horse that presented with multiple variably sized skin nodules, some of which ulcerated. Visceral leishmaniosis was diagnosed in a stray dog. Cytological, histopathological, and mol...
Stimpson S, Molloy E, Davis BW, Esparza B, Rosa LP, Illanes O.Grey coat color in horses, resulting from a 4.6 kb copy number variation (CNV) within the syntaxin 17 (STX17) gene (Grey locus), is linked to progressive hair depigmentation and a markedly increased risk of melanoma, likely to its function as a melanocyte-specific enhancer. Objective: This report details the clinical, pathological, and genomic findings of a 26-year-old flea-bitten grey mare with multiple melanocytic tumors, progressive dyspnea, and congestive heart failure. Due to the poor prognosis the horse was euthanized and submitted for necropsy to the Long Island University - Lewyt Colle...
Pineda V, Calzada JE, Montilla S, Rodríguez I, Howard E, Torres AI, Vasquez V, Reina A, Saldaña A, González K. (CL) is a vector-borne zoonotic disease affecting the skin and mucous membranes of animals and humans. While CL is commonly diagnosed and studied in humans in Panama, limited information exists on its occurrence in domestic animals and their potential role as reservoirs. In this study, samples from twelve domestic animals (ten dogs and two horses) with suspected CL lesions were collected between 2021 and 2025 in endemic regions of Panama and evaluated using multiple diagnostic methods. infection was confirmed in six of them (50%): five dogs and one horse. Three dogs were infected with () , ...
Ribeiro MG, Barbosa AN, Pereira JG, Possebon FS, Pinto JPAN, Portilho FVR, Bello TS, Paz PJL, Arabe Filho MF, Panegossi LC, Reznik AU, Zeferino LO....Rhodococcus equi, a versatile and adapted opportunistic in nature bacterium, infects animals and humans. This soil-borne microorganism widely occurs in farms. Its dissemination occurs by feces from domestic animals (particularly horses, cattle, and pigs). In the last decades, bacterial virulence has been strongly attributed to plasmid-encoded virulence-associated proteins (VAPs). To date, three virulence plasmid types have been recognized: pVAPA, pVAPB, and pVAPN, which are considered host- or livestock-adapted. The pVAPA type is related to equine isolates (horse-type), the pVAPB type is assoc...
Kern-Allely C, Scott D, Magzamen S, Duncan C.Air pollution is a major global health threat that is expected to worsen, yet its effects on domestic animals remain poorly understood. The objective of this scoping review was to synthesize existing evidence on associations between ambient air pollutants and health outcomes in domestic animals and to identify gaps to guide future research. Unassigned: A scoping review was conducted following the Arksey and O'Malley framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines with 2 search databases (PubMed and Web of Science) using ...
Prasad S, Patel B, Kumar P, Lall R.Postbiotics, which are preparations of inanimate microorganisms and their components, have emerged as a promising functional ingredient in animal health and nutrition. Postbiotics are primarily composed of microbial cell fractions, metabolites, enzymes, vitamins, polysaccharides, and short-chain fatty acids. Unlike probiotics, postbiotics do not contain live microorganisms, which strengthens their greater stability and safety in feed/food formulations. Postbiotics offer several beneficial effects, including antioxidant, anti-inflammatory, immune-modulatory, and antimicrobial actions. They enha...
Karaushi H, Yoshitake A, Kanazawa Y, Watanabe N, Tokano M, Seki M, Mitsutake K.A 69-year-old woman with hypertension had undergone total arch replacement with an open stent graft 7 years prior. She was referred to our hospital for evaluation after experiencing fever (>38 °C) and cough. Chest radiography revealed a prominent aortic arch, and contrast-enhanced computed tomography demonstrated aortic arch enlargement and peri-graft fluid collection containing air. These findings indicated graft infection and prompted immediate intervention. Blood cultures grew Streptococcus equi subspecies zooepidemicus, a zoonotic pathogen associated with horses. Notably, the patient wor...
Iwasaki N, Llewellyn J, Brown J, Zamboulis DE, Finding EJT, Wheeler-Jones CPD, Thorpe CT.Tendon degeneration is common, and its risk increases with age both in humans and horses. Tendon regeneration and healing is limited due to inherent low cell density and vascularisation, and current treatments are insufficient as indicated by scar tissue formation and a high re-injury rate. The tendon vasculature plays a crucial role in tendon homeostasis, regeneration and healing, making it a potential therapeutic target. However, the effect of ageing on the tendon microvasculature is poorly understood. Here, we provide the first comprehensive characterisation of the tendon microvasculature. ...
Thompson JR, Barcalow S, Stark A, Scoggin KE, Conley AJ, Loux SC.Luteinizing hormone (LH) plays a pivotal role in equine reproductive physiology, yet its measurement has traditionally relied on radioimmunoassays (RIA), which present safety, accessibility, and regulatory challenges. This study evaluates the use of a commercially available pregnant mare serum gonadotropin (PMSG) enzyme-linked immunosorbent assay (ELISA) as an alternative for quantifying circulating LH in horses. Given the 100% peptide identity between equine LH and PMSG, we hypothesized that the PMSG ELISA would detect LH with high specificity and sensitivity. Blood samples from healthy, cycl...
Sunderland KA, Affolter VK, Cassano JM, Berryhill EH, Morgan JM.To determine the main causes of death in aged horses residing at a retirement facility in California. Unassigned: A retrospective cross-sectional study design was utilized to evaluate signalment, medical history, and necropsy reports of horses aged 20 years or older at death and housed at a single retirement facility. All cases underwent a standard post mortem evaluation from 2010 through 2020 by the University of California-Davis William R. Pritchard Veterinary Medical Teaching Hospital. Euthanasia decisions were made by the retirement facility staff in consultation with a veterinarian. The m...
Secor E, Thomas M, Chu E, Hazzard S, Raimondi S, Reesink H.To investigate whether IA hydrogel therapeutics alter the inflammatory and/or degradative responses of articular cartilage (AC) and synovial membrane (SM) to cytokine stimulation. Unassigned: AC and SM tissue explants were stimulated with interleukin-1β (IL-1β) or tumor necrosis factor-α (TNF-α) and simultaneously treated with triamcinolone acetonide, hyaluronic acid, collagen-elastin hydrogel microparticles (CEHM), or 2.5% polyacrylamide hydrogel (2.5% iPAAG) at 3 doses. Synovial membrane (n = 9 explants, 3 horses) was stimulated/treated for 18 hours, whereas AC (12 explants, 6 horses) wa...
de Araujo EAB, Papa FO, de Oliveira Baldini PH, de Paula Freitas-Dell'Aqua C, de Oliveira SN, Silva LFMC, Junior LRPA, Rodrigues LT, Monteiro GA.Despite advances in the method, equine semen cryopreservation still leads to a marked decline in sperm quality, partly attributed to oxidative stress, which motivates the search for lipophilic antioxidants capable of stabilizing the plasma membrane during cooling and freezing. This study performed three experiments to evaluate butylated hydroxytoluene (BHT) as an additive to commercial skim milk-based (Botu-Sêmen) and egg yolk-based (Botu-Crio) extenders. In Experiment 1, a dose-response curve (0.5, 1.0, and 1.5 mM) was performed using stallion semen to assess toxicity and establish a safe ...
Leith GS, Hallam L, Englar RE.The ninth standard of accreditation as outlined by the American Veterinary Medical Association (AVMA) Council on Education (COE) mandates that all accredited colleges of veterinary medicine must provide instruction in medicine and surgery, including principles of practice, hands-on experiences with diagnostic methods, and interpretation of clinical findings. In equine practice, diagnostic imaging is used as a first-line diagnostic approach and is an integral part of pre-purchase and lameness examinations. Accuracy and consistency of radiographic interpretation relies heavily upon procedural te...
Weeks RA, McLAUGHLIN PA, Vaughan BR.Equestrians (horse riders) are more susceptible to low back pain than the general population due to loads placed on their bodies during the activity. A specific eight-week exercise intervention program targeting the muscles used during horse riding was implemented for a group of equestrians with low back pain. Methods: Volunteers were invited to participate in the study through social media posts in Melbourne, Australia. The participants were required to complete an exercise screening test prior to enrolment in the study to ensure they were suitable to participate in the iteration program. Par...
Shimizu Y, Sugai-Bannai M, Saito K, Hirano-Kodaira M, Leung GN.Somapacitan, a long-acting growth hormone derivative, and recombinant human growth hormone (rhGH) are protein-based drugs generally used to treat growth disorders and GH deficiency in humans. Due to their potential to enhance the horse performance, the use of these drugs is prohibited at-all-times by the International Federation of Horseracing Authorities for horseracing and the Fédération Equestre Internationale for equestrian sports. In this study, we developed a test method for the identification and differentiation of somapacitan and rhGH in equine plasma by using liquid chromatography h...
Steel R, Timms M, Bamford N, Spence R, Sillence M.Previous liquid chromatography/mass spectrometry (LC/MS) methods for the detection of insulin and other similar peptide hormones in equine plasma relied on the use of antibody affinity extraction. As a result, these methods were not suitable for routine high-throughput analysis. A solid-phase extraction (SPE) method incorporating size exclusion as well as reversed-phase interactions allows the selective extraction of peptide hormones such as adrenocorticotropic hormone (ACTH), insulin and their synthetic analogues from equine plasma with approximately 80% extraction efficiencies. This extracti...
Emiru AY, Regassa F, Endebu Duguma B, Kassaye A, Desyebelew B.Effective therapy for many infections is becoming difficult due to the evolutionary development of drug resistance, and hence, the development of alternative treatment options mainly from herbs is crucial. The objective of this study was to investigate the antibacterial effects of ethanol extracts of stem bark, leaves and roots of Combretum molle against Streptococcus equi isolated from clinical cases of strangles using in vitro tests. Methods: Plant extraction was performed using a maceration technique with 80% ethanol. The mean zone of inhibition was determined using the agar well diffusion ...
Leduc L, Underwood C, Stefanovski D, Hurcombe S, Navas de Solis C.To assess whether remote assistance is beneficial to the accuracy of point-of-care ultrasound (POCUS) examinations during equine emergency evaluations. Methods: Adult horses presenting to a tertiary care large animal emergency service for respiratory or gastrointestinal clinical signs. Methods: Prospective, randomized, controlled, clinical study. Cases were assigned to receive POCUS with remote assistance ("POCUS-R" group) or POCUS with no assistance ("POCUS" group). Accuracy of diagnosis, duration of sonograms and survival to discharge were the objective outcomes compared between groups. Perc...
Girma T, Chala G, Mekibib B.Epizootic lymphangitis is an infectious and chronically debilitating disease of the equines. Histoplasma capsulatum var. farciminosum, a thermally dimorphic fungi, is the causative agent for the disease. In Ethiopia, the disease significantly affects carthorses, posing threats to animal welfare, and resulting in substantial economic losses. Limited availability of widely accessible antifungals in addition to the chronic nature of the disease is the major challenge against management of epizootic lymphangitis. This study aimed to assess the in vitro efficacy of specific local medicinal plant ex...
Nascimento C, Saraiva MVA, Pereira VM, de Brito DCC, de Aguiar FLN, Alves BG, Roballo KCS, de Figueiredo JR, Ambrósio CE, Rodrigues APR.The regenerative therapies with stem cells (SC) has been increased by the cryopreservation, permitting cell storage for extended periods. However, the permeating cryoprotectant agents (CPAs) such as dimethylsulfoxide (DMSO) can cause severe adverse effects. Therefore, this study evaluated equine mesenchymal stem cells derived from adipose tissue (eAT-MSCs) in fresh (Control) or after slow freezing (SF) in different freezing solutions (FS). The FS comprise DMSO and non-permeating CPAs [Trehalose (T) and the SuperCool X-1000 (X)] in association or not, totalizing seven different FS: (DMSO; T; X;...
