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.
Dalgleish R, Love S, Pirie HM, Pirie M, Taylor DJ, Wright NG.A natural outbreak of strangles occurred in a group of 19 young experimental ponies. The disease was diagnosed in 11 of them within two days of their arrival at Glasgow University veterinary school and five others developed clinical signs within a further four days, a morbidity rate of 84 per cent. All of the affected ponies had typical signs of strangles including dullness, anorexia, pyrexia, regional lymphadenitis, occasionally with rupture of the lymph node, conjunctivitis and a mucopurulent nasal discharge. Nine of the affected ponies were destroyed during the clinical phase of the disease...
Marr CM, Love S, Boyd JS, McKellar Q.Ultrasonographic examination was used to define the severity of injuries to the superficial digital flexor tendon in 73 National Hunt or point-to-point racehorses and the factors influencing the outcome of the cases were examined. Thirty-four of the horses (46 per cent) returned to work with an average time out of training of 13.5 months. The rate of recurrence of the injury was 35 per cent. The severity of the lesions was related to the outcome; all the mildly affected horses returned to work, with 63 per cent of them racing and an average time out of training of 10.2 months; 50 per cent of t...
Hannant D, Jessett DM, O'Neill T, Dolby CA, Cook RF, Mumford JA.An experimental (ISCOM) vaccine previously shown to protect hamsters from lethal challenge with equid herpesvirus-1 (EHV-1), was tested in horses. Vaccination with EHV-1 ISCOMs induced serum antibodies to the major virus glycoproteins gp10, 13, 14, 17, 18 and 21/22a, whereas antibody responses to gp2 were weak or absent. High levels of virus neutralising antibody of long duration were induced, but did not prevent challenge infection with virus of the homologous strain. However, in the vaccinated ponies there was a significant reduction in clinical signs, nasal virus excretion and cell associat...
Jones DL.The effectiveness of detomidine with or without atropine sulfate premedication in producing sedation and analgesia for arthrocentesis was studied in 12 horses. The effects were evaluated by monitoring heart and respiratory rates, borborygmi, distance from the lower lip to the floor, systolic blood pressure, and response to needle insertion. Either atropine or saline (as a placebo) was administered immediately prior to detomidine. All drugs were administered intravenously. Measurements were taken prior to drug injection and at 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 120, 180 and 240 minutes posti...
Edens LM, Morris DD, Prasse KW, Anver MR.Protein C is a vitamin K-dependent serine protease with anticoagulant and profibrinolytic activity which is synthesized in the liver. Decreased protein C activity was detected in a Thoroughbred colt with clinical and histopathologic evidence of recurrent venous thrombosis. Although protein C activity was reduced, protein C antigen concentration was normal. Consumptive coagulopathies produce a decrease in both the functional and antigenic concentrations of protein C, thus a defect in protein C synthesis was suspected. Inhibition of gamma-carboxylation secondary to vitamin K antagonism results i...
Reimer G, Suarez A, Chui YC.A standardbred mare was dosed with 40 mg yohimbine intravenously. Serum and urine samples were collected and analyzed for yohimbine using solvent extraction and reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. Maximum yohimbine concentrations of 45 and 18 ng/mL were observed in serum and urine samples, respectively. Elimination was rapid, with half-lives of approximately 20 and 53 min observed for serum and urine, respectively. The presence of yohimbine in these samples was confirmed by liquid chromatography/mass spectroscopy (LC/MS/MS).
Proudman CJ, Edwards GB.Faeces samples from 116 horses with colic and 115 non-colic cases were assayed by a centrifugation/floatation method for the presence of tapeworm eggs. Analysis of these data failed to demonstrate an association between tapeworm infection and colic of all types. The data were further analysed according to anatomical site of the lesion causing colic. The risk of ileocaecal colic was increased in the presence of tapeworms. Age, breed and sex were evaluated as possible confounding factors but had no association with the incidence of colic. This study suggests an association between tapeworms and ...
Tate LP, Corbett WT, Bishop BJ, Foreman JH.The physiologic effects of exercise were studied in four horses with complete laryngeal hemiplegia. Right carotid arteries were surgically elevated to a subcutaneous position for percutaneous catheterization. Each horse was fitted with a device designed to obtain multiple arterial samples while the horse was exercised over a 1.6-km course. After each horse completed 10 test gallops, the laryngeal hemiplegia was treated using a laryngeal prothesis and ventriculectomy. The horses were then reconditioned, and the exercise test and sampling were repeated. Horses with laryngeal hemiplegia became ac...
Mair TS, Brown PJ.Thirty-eight horses with confirmed thoracic neoplasia included 28 (37.7%) with lymphosarcoma, 4 (10.5%) with metastatic renal cell carcinoma, 2 (5.3%) with primary lung carcinoma, 2 (5.3%) with secondary squamous cell carcinoma from the stomach, 1 (2.6%) with pleural mesothelioma, and 1 (2.6%) with malignant melanoma. The major clinical features included weight loss, inappetence, dyspnoea and coughing, but in cases of lung metastases, they related more to the primary site of tumour formation. Haematological and serum biochemical abnormalities were non-specific. Specific pre-mortem diagnosis wa...
Prieto D, Hernandez M, Rivera L, Ordaz E, Garcia-Sacristan A.The aim of the present study was to determine the distribution and density of catecholaminergic nerve fibres and cells in the equine ureter by using immunohistochemical techniques to localise the enzyme tyrosine-hydroxylase (TH). TH-immunoreactive (TH-IR) nerve fibres entered the wall of the ureter as adventitial nerve trunks accompanying the blood vessels. These trunks repeatedly branched as they coursed through the muscular layer towards the epithelium, forming muscular, perivascular and subepithelial nerve plexuses. TH-IR nerve fibres were especially numerous in the pelvic and intravesical ...
Johnson CM, Cullen JM, Roberts MC.Ten ponies (160-250 kg, ages 17 months to 20 years) developed severe diarrhea within 24 hours of castor oil administration (2.5 ml/kg orally). The diarrhea was most severe between 24 and 48 hours post-dosing and subsided by 72 hours. Ponies were euthanatized at 24, 48, and 72 hours post-dosing and intestine was evaluated histologically and ultrastructurally. Twenty-four hours after dosing, the mucosa of the cecum and ventral colon had extensive superficial epithelial erosion and neutrophil infiltration. In the ileum, the epithelium of villous tips was separated from the lamina propria. Scannin...
Oikawa M, Katayama Y, Yoshihara T, Kaneko M, Yoshikawa T.The morphology of the arteries in the uterine wall was studied in three multiparous aged mares that had suffered repeated pregnancy failure. The uterine wall arteries exhibited elastosis of the intima or adventitia, or both, resembling "physiological pregnancy sclerosis". In areas affected by elastosis, degeneration of the pre-existing elastic fibres and increased glycosaminoglycans were frequently observed. Newly formed elastic fibres were not evident. Delayed resorption due to disordered metabolic turnover of the elastin was thought to be an important factor in the pathogenesis of the arteri...
Allen WR, Skidmore JA, Stewart F, Antczak DF.Measurement of the concentrations of equine chorionic gonadotrophin (eCG) in the serum of pregnant mares and Jenny donkeys carrying normal intraspecies and hybrid interspecies pregnancies suggested that the production of this hormone may be influenced by parental gene imprinting. Specifically, a differential expression of maternal and paternal genes may control the size and secretory activity of the structures that secrete eCG, the fetal endometrial cups. However, bisection of an interspecies mule embryo followed by transfer of the resulting demi-embryos and other intact mule embryos to horse ...
Carter BG, Schneider RK, Hardy J, Bramlage LR, Bertone AL.Fractures of the humerus were diagnosed in horses at The Ohio State University Veterinary Teaching Hospital. Twenty-four horses (44.4%) were destroyed after radiographic assessment (mean age of 5.0 years). Surgical treatment was elected in 13 horses (24.1%, mean age of 0.42 years). Conservative management, consisting of prolonged stall rest, was chosen for 17 horses (31.5%, mean age of 2.2 years). In the surgically treated group, 3 foals (23.1%) all less than 2 months of age at the time of fracture and treated with intramedullary stack pinning, survived and became athletically sound. After con...
Borne AT, MacAllister CG.The effect of sucralfate on healing of subclinical gastric ulcers and gastric inflammation was investigated in twelve 6- to 7-month-old foals. Foals with endoscopically evident gastric lesions on day 0 were assigned to 1 of 2 groups, on the basis of mucosal inflammation and number and severity of ulcers, to create groups of foals with approximately equal severity of lesions. None of these foals had clinical signs of gastroduodenal ulcer disease. Groups were assigned to receive sucralfate (22.0 mg/kg of body weight) or corn syrup for 14 days, PO, every 8 hours. On day 15, gastroscopic examinati...
Amri H, Gaillard JL, al-Timimi I, Silberzahn P.Mare granulosa cells and cyclic corpus luteum microsomes are reported to aromatize 19-norandrogens more efficiently than androgens. However, 16 alpha-hydroxytestosterone and epitestosterone were not aromatized by the equine corpus luteum microsomal estrogen synthetase. These results indicate that the equine aromatase system would be different from the human placental microsomal estrogen synthetase, which aromatizes 16 alpha-hydroxyandrogens and epitestosterone but not 19-norandrogens. Furthermore, our data show that the rates of aromatization of androgens and 19-norandrogens were not additive ...
Lumsden JM, Derksen FJ, Stick JA, Robinson NE.Flow-volume loops generated from 6 Standardbreds at rest and during treadmill exercise were evaluated for their use in detecting upper airway obstruction. Tidal breathing flow-volume loops (TBFVL) were obtained from horses at rest and exercising at speeds corresponding to 75% of maximal heart rate and at maximal heart rate. The TBFVL were evaluated, using a pulmonary function computer; calculated indices describing airflow rate and expiratory-to-inspiratory airflow ratio for individual loops were determined. In addition to TBFVL indices, standard variables of upper airway function also were me...
Harris PA.The effect of feeding diets with low, adequate and high sodium contents on plasma aldosterone concentrations in horses and ponies was evaluated using human immunoassay kits. The effect of moderate to high intensity exercise of up to six minutes duration on plasma aldosterone concentrations in three thoroughbred horses was also investigated. On an adequate sodium diet plasma aldosterone concentrations increased to a peak around four hours after feeding. Little daily variation was found in the pre-feeding aldosterone concentrations over three days. Feeding additional salt resulted initially in n...
Sonea IM, Bowker RM, Broadstone RV, Robinson NE.The tone of respiratory smooth muscle is largely determined by the input from autonomic nerves. The distribution of adrenergic and selected nonadrenergic, non-cholinergic (NANC) nerves in the normal equine trachealis muscle was investigated using immunohistochemistry. The smooth muscle of the trachealis was found to contain numerous nerves immunoreactive for an enzymatic marker of adrenergic nerves, as well as many nerves immunoreactive for a putative NANC neurotransmitter, peptide histidine isoleucine, a potent bronchodilator. The tissue surrounding the respiratory smooth muscle contained num...
van der Kolk JH, van Hoorn CJ, van Garderen E, van den Belt AJ.An eighteen-year-old pony gelding was referred to the Faculty of Veterinary Medicine because of colic, due to cecal tympany. His haircoat was dull with long wavy hair. After medical treatment of the colic it was sent home three days later. Just before it had been dismissed the morning plasma glucose concentration measured 10.2 mmol.l-1. The basal plasma cortisol concentration was high (180 nmol.l1) and basal plasma ACTH concentration was highly elevated (> 960 pg.ml1). An ACTH-stimulation test was performed by intravenous administering of 0.25 mg synthetic ACTH 1 24 at 9.00 hours showing ad...
Ellington JE, Ball BA, Yang X.The objective of this study was to determine whether coculture of stallion spermatozoa and mare oviductal (uterine tubal) epithelial cells induced sperm cell capacitation in vitro. Capacitation as determined by zona binding and chlortetracycline staining of the sperm cells was compared for stallion spermatozoa: (1) incubated with medium alone (negative control), (2) treated with calcium ionophore A23187 (positive control) or (3) cultured with mare oviductal epithelial cells (OEC) for 4 h. Chlortetracycline staining patterns of sperm cells bound to the zonae were used to group spermatozoa as un...
McKeever KH, Hinchcliff KW, Reed SM, Robertson JT.Six intact and 6 splenectomised mares were given an incremental exercise test on a treadmill to examine the fluid and electrolyte changes associated with exercise and the role of the spleen in these changes. Blood samples were obtained at rest and at the end of each 1-min step of the test. Exercise at 7 m/sec caused significant (P 0.05) in either group (intact = 2.7%; splenectomised, = 3.5%). This appears to be the first record of substantial changes of these constituents during short-term exercise, even before the onset of visible sweat losses. The changes in the concentration of plasma prot...
Tate LP, Corbett WT, Foreman JH, Bishop BJ, Sweeney CL.A device was constructed of easily obtained medical supplies, and hardware and could be used to obtain multiple arterial samples when manually triggered. The right carotid arteries in five normal horses were surgically elevated, thereby permitting percutaneous cannulation. Each horse was galloped on a 1.6-km test track at approximately 500 m/min, and the rider triggered the mechanism at each 0.4-km mark. Each horse underwent 10 test gallops, and a mean and standard error was determined for each sampling mark including preexercise and postexercise samples. The results indicated that horses ridd...
Socha W, Larska M, Rola J.Susceptibility to long-term persistent infection with Equine Arteritis Virus (EAV) in stallions is related with EqCXCL16 gene alleles of the host. In our study EqCXCL16 gene alleles were determined for 63 EAV shedders and 126 non-shedders of various horse breeds. In total, 60 (31.7%) out of 189 tested stallions were identified as carriers of susceptible variants of EqCXCL16 by real time PCR and Sanger sequencing. The presence of susceptible genotype was related to horse breed with the highest percentage in Wielkopolska breed, Polish coldblood and Silesian breed horses. Strong correlation betwe...
Kamm JL, Bramlage LR, Schnabel LV, Ruggles AJ, Embertson RM, Hopper SA.Analysis was performed to examine a method for refining the preoperative prognosis for horses that had surgery to remove apical fractures of the proximal sesamoid bones (PSBs). Objective: To determine if: 1) there was a difference in size or configuration of apical fractures between the different anatomical locations of the PSBs, which have been shown to affect the prognosis; and 2) the size or configuration could predict the prognosis for racehorses with these fractures. Methods: The study included 110 weanlings and yearlings and 56 training racehorses that underwent surgery to remove apical ...
Hempstead JE, Clode AB, Borst LB, Gilger BC.To evaluate corneal changes associated with chronic, nonhealing, superficial, corneal ulcers in horses via common histopathological stains. Methods: Retrospective study. Methods: Twenty-four horses diagnosed with chronic, nonhealing, superficial, corneal ulceration. Methods: The medical records of horses evaluated at North Carolina State University's Veterinary Teaching Hospital (NCSU-VTH) from 2005 to 2011, diagnosed with a chronic, nonhealing, superficial, corneal ulcer and treated with superficial keratectomy (SK) were reviewed. Inclusion criteria were superficial corneal ulceration, no cel...
Weaver BM, Webb AI.The halothane muscle/gas partition coefficients at 37 degrees C for 26 samples of eight different muscles from four horses were found to depend significantly on the fat content of the muscle sample with a regression coefficient of 1.913 (SEM 0.109) per per cent ether-extractable fat content. The blood/gas partition coefficients in 24 horses showed a significant dependence on plasma triglyceride concentration (regression coefficient 0.00084 (SEM 0.00033) per mg dl-1), an insignificant positive dependence on plasma free and total cholesterol concentration and, in a multiple regression analysis, ...
Steinmetz A, Gittel C, Böttcher D, Lapko L, Offhaus J.A melanoma of the upper eyelid was resected in a gray warmblood gelding. A full functional eyelid could be obtained by completion a sliding skin graft with a free labial mucocutaneous graft transplantation to restore the mucocutaneous junction and to decrease the risk of postoperative trichiasis.
Galey FD, Beasley VR, Schaeffer D, Davis LE.An aqueous extract was made from black walnut (Juglans nigra) heartwood obtained in the fall of the year. Ten hours after nasogastric administration of 5 L of the extract, a 550-kg, 13-yr-old Quarter Horse gelding experienced Obel grade-3 laminitis. The effect of aqueous extract of black walnut on vascular contractility was then tested, using isolated equine digital arteries and veins. The vessels were maintained in Krebs bicarbonate buffer with 95% oxygen at 37 C. The extract did not induce a direct contractile effect. It did, however, reversibly enhance the vasoconstriction induced in the is...
Hussein HA, Ibrahim A, Ali MF.This study aimed to establish normal ultrasonographic reference values of kidney dimensions in donkeys (Equus asinus) and to describe and evaluate the clinicopathological variations associated with ultrasound-guided renal biopsy. The ultrasonographic dimensions of the right and left kidneys were conducted on 16 donkeys, which were then divided into two groups; eight each for biopsy of the right kidney (RK) and left kidney (LK). Three ultrasonographic cineloops were obtained at 17th intercostal space daily for 3 consecutive days. Renal length, width, and dimensions of the cortex, medulla, and p...
Perryman LE.Primary immunodeficiency disorders are genetically determined failures of immune defense that increase susceptibility to infectious agents. This article reviews the salient features of equine primary immunodeficiency disorders, summarizes the molecular mechanisms of each disorder, and updates information that facilitates diagnosis and management of affected horses. The central theme is to encourage clinicians to ask, "I wonder if this horse has an underlying primary immunodeficiency disorder?" when caring for horses suffering from chronic and recurring infections and responding poorly to stand...
Winter MD, Berry CR, Reese DJ.Nuclear scintigraphy has been used successfully for various applications in horses in the past 30 years. Many private practices and most veterinary schools have gamma cameras, which are used to image an injected radionuclide in an equine patient. Unique exercise-related demands place specific physiologic stressors on the musculoskeletal system of horses. Horses are often pushed beyond normal physiologic limits because of specific performance stresses; therefore, injury to their musculoskeletal system is common. Skeletal scintigraphy is exceedingly sensitive but relatively nonspecific for deter...
Tetens J, Venugopal CS, Holmes EP, Koch CE, Hosgood G, Moore RM.To evaluate the in vitro effects of adenosine tryphosphate (ATP) on vasomotor tone of equine colonic vasculature. Methods: Arteries and veins from the left ventral colon of 14 mixed-breed horses euthanatized for reasons unrelated to cardiovascular or gastrointestinal tract disease. Methods: Endothelium-intact and -denuded arterial and venous rings were precontracted with 10(-7) and 1.8 x 10(-8) M endothelin-1, respectively. In 1 trial, endothelium-intact rings were also incubated with 10(-4) M N omega-nitro-L-arginine methyl ester (L-NAME) to inhibit nitric oxide (NO) production. Adenosine tri...
Sigel CW, Byars TD, Divers TJ, Murch O, DeAngelis D.Two fasted and 2 fed horses were dosed orally with a combined trimethoprim and sulfadiazine paste formulation at a dose of 35 mg (1:5 combined active ingredients)/kg. Serum concentrations of each drug were determined periodically for 3 consecutive days for the 4 horses. The extent and rate of absorption for trimethoprim were variable, but peak serum concentrations occurred generally within 3 hours; sulfadiazine absorption was slower, reaching peak concentrations by 6 hours. Fasting did not have a consistent effect on the serum concentration profiles for either drug. Both drugs achieved serum c...
Carpenter TE, McBride MD, Hird DW.We examined the risk of importing and mistakenly releasing equine infectious anemia virus (EIAV)-infected horses into California. A computer simulation model was constructed to evaluate current and alternative quarantine station procedures; 150,000 iterations were performed to simulate 15 different scenarios of 10,000 horses imported into the state over a 14-year period. Simulation results showed that under current conditions of low EIAV prevalence in exporting countries, increasing the quarantine period would not decrease the number of EIAV-infected horses mistakenly released from quarantine....
Bertero A, Ritrovato F, Evangelista F, Stabile V, Fortina R, Ricci A, Revelli A, Vincenti L, Nervo T.The purpose of this study was to observe -matured equine oocytes with an objective computerized technique that involves the use of a polarized light microscope (PLM) in addition to the subjective morphological evaluation obtained using a classic light microscope (LM). Equine cumulus-oocyte complexes (COCs, = 922) were subjected to different maturation times (24, 36 or 45 h), however, only 36-h matured oocytes were analyzed using CLM. The 36-h matured oocytes that reached maturity were parthenogenetically activated to evaluate the quality and meiotic competence. Average maturation perce...
Rankins EM, Manso Filho HC, Malinowski K, McKeever KH.Horses' muscular tension during acute stress remains unexplored. Our aim was to assess muscular, behavioral, cortisol, and hematocrit responses to social isolation (ISO), novel object exposure (NOV), and sham clipping (CLIP). Altered stress responses were expected. Eight mature Standardbred horses (four mares and four geldings) were exposed to acute stressors and a control period (CON) in a balanced, replicated 4×4 Latin Square experimental design with 3 min treatment periods and 10 min washout periods. Surface electromyography collected from the masseter, brachiocephalas, cervical trapeziu...
Ewert M, Böröcz J, Uphaus H, Oldenhof H, Distl O, Sieme H.The aim of this study was to evaluate factors affecting pregnancy rates in the German Thoroughbred Breed with particular emphasis on optimisation of fertility rates for breeding stallions of older ages. Methods: Data from the studbooks of the German Thoroughbred Breeding Association from 1996 to 2009 analysed. This analysis included the records of 319 stallions and 6622 brood mares, resulting in 21,372 pregnancies at the end of the season. Results: Pregnancy rates were significantly affected by the age of the stallion and mare as well as the season (month in the breeding season in which coveri...
Murase H, Matsui A, Endo Y, Sato F, Hada T.The lying behavior of Thoroughbred foals on breeding farms was continuously measured using triaxial accelerometers. Accelerometers were attached on the side of the hind limb cannon and under the halter of six foals to record triaxial angle data every 10 sec for a period of 24 hr. Lying behavior was divided into sternal lying and lateral lying based on head angle. Sampling was performed for two consecutive days each week until weaning. Sampling periods were divided into two periods on the basis of pasturing time: daytime pasturing (period A: 7-hr pasturing period, 2-60 days of age) and overnigh...
Doyle AJ, Freeman DE, Rapp H, Murrell JA, Wilkins PA.To report our experience with horses that presumptively had severe intraluminal hemorrhage from enterotomy or anastomosis. Methods: Clinical study. Methods: Six adult horses and 1 adult donkey. Methods: A retrospective study was conducted at the University of Illinois (April 1994 to December 2001) to determine the clinical course and outcome of horses with melena and/or anemia and evidence of life-threatening hemorrhage from intestinal incisions. Medical records of all horses that had colic surgery were reviewed to determine the proportion of horses with this complication. In addition, horses ...