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.
Craig TM, Courtney CH.The kind of parasites a horse acquires depends upon its environment. Because patterns of transmission vary greatly with climate and management, no one worming program has universal applications. This article discusses epidemiology and control of equine parasites in the southern United States, where climates vary from warm temperate to subtropical and from humid in the southeast to arid in the southwest.
McDonnell SM, Garcia MC, Blanchard TL, Kenney RM.Ten pony mares that had developed stallion-like sexual behavior as the result of anabolic steroid treatment (boldenone undecylenate, 0.55 mg/kg intramuscularly (i.m.), once weekly for 12 injections) were evaluated for ability to aid in detecting estrus in cycling mares. In across-the-fence estrus detection trials, androgenized mares failed to elicit signs of estrus or diestrus. In 10-min pasture trials, in which each androgenized mare was placed in a group of 10 cycling mares (six of which were estrous), seven of the 10 androgenized mares elicited estrous behavior from one or two mares. Observ...
Andrews FM, Spurgeon TL.The histologic and histochemical staining characteristics of the triceps brachii (long head), extensor carpi radialis, gluteus medius, vastus lateralis, biceps femoris, semimembranosus, semitendinosus, and extensor digitorum longus muscles of 8 Thoroughbreds, 2 Quarter Horses, 1 Arabian, 1 Paso Fino, and 1 Shetland Pony are described. Muscle fiber morphology, staining distribution and intensity, amount of IM connective tissue, number of IM blood vessels and IM nerves, calcium-activated adenosine triphosphatase activity (CaATPase), percentage of fibertype population, percentage of relative fibe...
Roby KA, Reef VB, Shaw DP, Sweeney CR.A 15-year-old, Standardbred broodmare with an aortic sinus aneurysm developed rupture of the aneurysm with subsequent rupture of a tricuspid valve chorda tendinae, tricuspid regurgitation, acute right-sided congestive heart failure, and pulmonary thromboembolism. Shunting of blood from the aorta through the ruptured aneurysm into the right ventricle resulted in decreased renal perfusion and acute renal failure. Initially, treatment of the mare with analgesics, fluids, and digoxin resulted in clinical improvement, but the mare's condition deteriorated after 8 days and the mare was euthanatized ...
van Berlo MF, Rottier PJ, Horzinek MC, van der Zeijst BA.Equine arteritis virus (EAV) is a nonarthropod-borne togavirus. Six virus-specific RNA species have been found in EAV-infected cells having the following molecular weights: 4.3 X 10(6) (RNA1), 1.3 X 10(6) (RNA2), 0.9 X 10(6) (RNA3), 0.7 X 10(6) (RNA4), 0.3 X 10(6) (RNA5), and 0.2 X 10(6) (RNA6). RNA1 comigrates with the viral genome (M. F. Van Berlo, M. C. Horzinek, and B. A. M. Van der Zeijst, 1982, Virology 118, 345-352). All RNAs hybridized with a radio-labeled cDNA probe representing RNA6, indicating that they contain common sequences. To study this homology in more detail, RNase T1 oligon...
Kinney RM, Johnson BJ, Brown VL, Trent DW.A cDNA clone containing all of the 26 S mRNA coding region of the RNA genome of Venezuelan equine encephalitis (VEE) virus, virulent strain Trinidad donkey (TRD), has been constructed and sequenced. The nucleotide and deduced amino acid sequences of the 26 S RNA of VEE virus conform to the general organization of the alphavirus subgenomic mRNA. Excluding the poly(A) tail, the VEE 26 S RNA is 3913 nucleotides long with a protein coding region of 3762 nucleotides. Codon usage in the translated region is nonrandom and correlates well with that reported for Sindbis (SIN), Semliki Forest (SF), and ...
Palmer JE, Whitlock RH, Benson CE.Equine ehrlichial colitis (Potomac horse fever), a newly identified colitis of the horse, was first recognized in Maryland. In this report, we document occurrence of the disease in Pennsylvania, New Jersey, New York, Ohio, Idaho, and Connecticut. Enzootic areas were recognized by a characteristic pattern. Frequently there was a seasonal pattern and high prevalence of sporadic colitis in unstressed horses. The attack rate per farm generally was low. Horses on pasture, as well as those stabled, were affected. Clinical signs varied from fever and depression to severe diarrhea and laminitis. Occas...
Andrews FM, Rosol TJ, Kohn CW, Reed SM, DiBartola SP.Three horses less than or equal to 3 years old were evaluated because of stunted growth, weight loss, anorexia, depression, and lethargy of at least 1 month's duration. A neonatal foal was examined after its death. In each case, gross and microscopic renal lesions were compatible with bilateral renal hypoplasia (ie, cortical hypoplasia with severe medullary hypoplasia). In young horses with renal failure, bilateral renal hypoplasia should be considered in the differential diagnosis, and may represent a congenital lesion.
O'Banion MK, Reichmann ME, Sundberg JP.Equine papillomaviruses (EqPV) from naturally occurring cases of cutaneous papillomatosis in several ponies and one horse were isolated, cloned, and characterized. Group specific papillomavirus structural antigens were detected in sections of the papillomas by the peroxidase-antiperoxidase technique, and virions were observed in the in the nuclei of cells in the stratum granulosum and corneum. Negatively stained virions purified from papilloma homogenates by isopycnic CsCl centrifugation were 55 nm in diameter and had typical papillomavirus morphology. The entire viral genomes of two separate ...
Koterba A, Torchia J, Silverthorne C, Ramphal R, Merritt AM, Manucy J.A base-line study of bacteria isolated from horses admitted to the Veterinary Medical Teaching Hospital during a 6-month period was performed to determine the extent of multiresistant nosocomial infections caused by gram-negative aerobic bacteria other than Salmonella spp. Results of this study indicated that 21.9% of the 105 horses from which cultures and sensitivities were available had developed nosocomial gram-negative aerobic infections, with high rates of resistance to gentamicin, kanamycin, and trimethoprim sulfadiazine, three of the most often prescribed antibiotics in this hospital. I...
Hacker DV, Moore PF, Buyukmihci NC.In 4 horses with ocular angiosarcomas, the common characteristics were that all horses were aged, and the neoplasms developed initially on conjunctival surfaces, grew slowly, and metastasized despite excision and radiation treatment. Histopathologically, the neoplasms were of 2 types: a capillary pattern of scant stroma and endothelial-lined vascular channels, and a solid pattern composed of sheets of pleomorphic cells with hyperchromatic nuclei and poorly defined cytoplasmic borders. Definitive diagnosis was made by use of factor VIII:RAg, which stained the tissues intensely.
Jones RS, Seymour CJ.The inhalational anaesthetic agent isoflurane was administered to 22 dogs and 21 horses undergoing a variety of surgical procedures. Satisfactory anaesthesia was produced in all the animals. The cardiopulmonary changes were similar to those observed with halothane. Rapid changes in the depth of anaesthesia were achieved and recovery from anaesthesia was rapid in both dogs and horses, which was a reflection of the relative insolubility of isoflurane. Recovery from anaesthesia in the horses was particularly smooth and rapid with the animals spending a greater part of their recumbency in the ster...
Masri MD, Merritt AM, Gronwall R, Burrows CF.Developmental changes of the gastrointestinal tract were probably responsible for the changes in faecal composition during the first week of the foals' life, which resembled small intestinal ingesta of adult horses, suggesting a minimal colonic modification. Faecal composition at the time of foal heat diarrhoea was suggestive of a secretory-type diarrhoea, in that the electrolyte concentration accounted for most of faecal osmolality and the faecal pH was alkaline. After foal heat diarrhoea faecal composition slowly approached that of adult horses. These data suggest that foal heat diarrhoea is...
Bowman KF, Dix LP, Riond JL, Riviere JE.Pharmacokinetics of ampicillin sodium (11 mg/kg), gentamicin sulfate (2.2 mg/kg), and combination ampicillin sodium-gentamicin sulfate were determined for serum and synovia of healthy horses given single-dose IV injection and were not found to be different from those from other reports; however, a prolonged terminal gamma-phase for gentamicin (8,498 +/- 1,842 minutes) in serum of horses was found to exist. Pharmacokinetic interaction between combination ampicillin sodium-gentamicin sulfate was not observed int he serum or synovia. Prediction of ampicillin sodium or gentamicin sulfate concentra...
Johnstone IB, Crane S.The incidence and nature of coagulation abnormalities in horses presented with colic and the possible prognostic value of these abnormalities was investigated. A coagulogram was performed on each of 24 adult Thoroughbred or Standardbred horses. A coagulogram consisted of measurements of eight parameters; platelet count, plasma fibrinogen, plasma antithrombin III (AT), partial thromboplastin time (PTT), prothrombin time (PT), thrombin clotting time (TCT), soluble fibrin monomer (SFM) and fibrin-fibrinogen degradation products (FDP). Retrospective determination of the cause of the colic and outc...
LeBlanc MM, McLaurin BI, Boswell R.Postpartum, presuckle, colostrum samples were collected from 100 mares. Colostral specific gravities significantly correlated (r = 0.9) with colostral immunoglobulin (Ig)G concentrations. Foal serum IgG concentrations highly correlated (r = 0.82) with specific gravities of the colostrum each foal ingested. Eight of 48 foals (17%) had serum IgG concentrations less than 400 mg/dl. The dams of these 8 foals had colostral sp gr less than 1.06 and colostral IgG concentrations less than 3,000 mg/dl. Foals had serum IgG concentrations greater than 520 mg/dl 24 hours after parturition, when the colost...
Ristic M, Holland CJ, Dawson JE, Sessions J, Palmer J.The recent establishment of a system for the continuous in vitro propagation of Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME; synonym, Potomac horse fever), has facilitated the development of an indirect fluorescent antibody test for the diagnosis of this disease under laboratory and field conditions. The field diagnostic application of the test has aided in the recognition of the disease in 16 states of the United States and in 1 province of Canada. A limited epidemiologic study conducted between January and September 1985, in an area where the disease is know...
Merritt T, Mallonée PG, Merritt AM.Seven healthy foals (five ponies and two horses) were maintained on grass pasture with their dams. All foals had normal faeces at the time of testing. An oral xylose absorption test was performed on each foal at one, two and three months of age. Following an 8 h fast, 0.5 g/kg D-xylose as a 10 per cent solution was given via a nasogastric tube. Control and 30 min interval plasma samples were collected for 3 h and the plasma was analysed for xylose using the phloroglucinol microassay technique. Maximum xylose concentration levels were reached between 30 and 60 mins for each of the foals. The me...
Becht JL, Byars TD.Gastroduodenal ulceration is becoming recognised as an important disease in foals during the first few months of life. Aetiopathogenesis is presumed to be similar to peptic disease in humans associated with back diffusion of hydrogen ions into the mucosa. Many factors have been incriminated as predisposing foals to ulceration but few have been proven. To date, use of non-steroidal anti-inflammatory agents has been the only documented cause of gastroduodenal ulceration in foals. The clustering of affected foals on certain farms suggests an infectious aetiology but attempts to identify a causati...
Bayly WM, Brobst DF, Elfers RS, Reed SM.Serum and urinary biochemical changes were recorded in 5 ponies in which acute tubular nephrosis had been induced over 5 days with mercuric chloride and potassium dichromate. Serum osmolality, the serum concentrations of urea nitrogen, creatinine, sodium, potassium and chloride, and blood pH and blood gases were measured daily for 14 days or until humane euthanasia was performed. Levels of the same substances were quantitated daily in urine. In addition, routine urinalyses and determination of urinary gamma glutamyl transferase (GGT) activity were performed on each sample. Changes in the value...
Brobst DF, Carroll RJ, Bayly WM.Urinary concentrations of gamma glutamyl transferase (GGT), alkaline phosphatase (AP), aspartate aminotransferase (AsAT), and alanine aminotransferase (AAT) were measured in 32 healthy horses (16 geldings and 16 females) at the same time on 2 consecutive days. The subjects were divided into 4 ages groups, each comprising 8 horses (4 of each sex). In 10 of the geldings, urine was collected continuously for 72 hours, with catheterized samples being obtained at 0800, 1400 and 2000 hours, and an aliquot of the pooled urine being taken every 24 hours. Urinary enzyme activity was found to be unrelat...
Greet TR, Whitwell KE.Twenty-five horses, suspected on clinical grounds of having grass sickness, were given a barium swallow. Using image intensification the passage of the barium bolus was followed radiographically from the pharynx to the stomach. All 18 horses in which grass sickness was later confirmed at post mortem examination showed defective oesophageal motility. Although the specificity of the abnormality could not be proven, the technique offers a valuable aid to the ante mortem diagnosis of grass sickness.
Pérez-Écija A, Estepa JC, Barranco I, Rodríguez-Gómez IM, Mendoza FJ, Gómez-Laguna J.Verrucous hemangiomas are a rare specific variant of equine skin tumors not well described in the literature. An 8-year-old gelding presented a unilateral lesion on the pastern. Macroscopically, the mass showed a warty and verrucous surface with focal ulcerations. The histology showed a dermal proliferation of endothelial-layered capillaries and venules separated by a delicate stroma of scant fibroblasts and collagen deposition, with pseudoepitheliomatous hyperplasia (exuberant reactive irregular epithelial hyperplasia with tongue-like projections extending into the dermis, mimicking downgrowt...
Firth EC, Poulos PW.Selective perfusion and microangiographic examination of the radius and metacarpus of 30 foals were performed. Vessels of extraosseous origin supplying the peripheral part of the metaphysis were not demonstrated in young foals, but became more obvious in older animals. The development of this vessel system coincided with the reduction of transphyseal vessels from the epiphysis crossing the growth plate.
Orsini JA, Roby KA.A modified surgical procedure for creation of a carotid loop for repeated percutaneous sampling of arterial blood gas was performed on 8 Holstein heifers and 14 horses. This approach permitted sampling of blood gas via fine-needle aspiration (one to three times daily) and/or catheterization for extended periods. It offers several advantages over previously reported techniques, including greater accessibility, absence of postoperative complications such as hematoma formation, and absence of foreign materials supporting the loop.
Althouse GC, Seager SW, Varner DD, Webb GW.An experiment was conducted to evaluate three commercially available test kits, the Azostix, Multistix and Uric-acid test, for the detection of urine in the equine ejaculate. Azostix, which tests for urea nitrogen, consistently detected urine in the equine ejaculate. Urine contamination was evident when a color change occurred in the reagent pad, going from yellow to green after 10 sec of exposure. The sensitivity of Azostix to urea nitrogen in contaminated samples was 39 mg/dl. The Multistix test kit also successfully detected urine in semen. In the Multistix nitrite pad the color changed fro...
Albrecht BA, MacLeod JN, Daels PF.At the onset of equine chorionic gonadotrophin (eCG) secretion, eCG stimulates luteal androgen and oestrogen production. Although eCG concentrations increase exponentially from day 37 to day 60 of gestation and eCG is detectable in maternal serum until about day 120-150 of gestation, luteal androgen and oestrogen production peaks between 5 and 10 days after initial exposure to eCG and then decreases gradually. It is not clear how eCG regulates luteal androgen and oestrogen production. In the present study, the steady-state mRNA expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cyto...
Blikslager AT, Tate LP, Weinstock D.Effects of neodymium:yttrium aluminum garnet (Nd:YAG) laser irradiation on equine endometrium were evaluated in vitro and in six mares with endometrial cysts. The Nd:YAG laser was applied to six endometrial sites, in each of five uterine specimens, with power densities of 5659 to 33,954 J/cm2. Depth of tissue ablation was measured and graded on histologic sections of the tissue lesions. Power density had a significant effect on the depth of tissue ablation (p < .001). Grade 3 lesions (full-thickness ablation of the endometrium) were created with energy densities of 16,977 to 33,954 J/cm2. Six ...
Andersson B, Augustinsson O, Bademo E, Junkergård J, Kvart C, Nyman G, Wiberg M.The primary aim of the study was to evaluate the potential value of intravenous (i.v.) infusion of angiotensin II (AII) for phonocardiographic differential diagnosis of equine valvular insufficiency. Ten-minute AII infusions at 4.5-33 pmol kg-1 min-1 induced clear-cut dose-dependent rises in systemic arterial blood pressure (aBP), whereas the pulmonary aBP remained largely unaffected. It implies that i.v. infusion of AII at about 10 pmol kg-1 min-1 could be a valuable tool for the acoustic differentiation between mitral and tricuspid valvular dysfunction in the horse. The infusion at, and abov...
Yoxall AT.The principles of radiological protection are summarised and consideration is then given to problems, which may confront the equine practitioner, in the fulfillment of these principles during diagnostic radiography of the limbs, head, and spine of the horse. The place of anaesthesia in such procedures is discussed and the special problems associated with therapeutic radiography of the horse are considered.
Denyer MS, Crowther JR.Antigenic differences within equine-1 and equine-2 isolates of influenza were studied by haemagglutination inhibition tests, indirect ELISA and competition ELISA, using the same antisera. Better differentiation was obtained with the competition ELISA than with the other two tests. All three methods produced similar relationships within the equine-1 isolates but differed in their ability to differentiate the equine-2 isolates where the competition ELISA was superior and produced epidemiologically sensible results. In all three tests, post-infection ferret and horse sera were more useful in disc...
Van Hoogmoed L, Rakestraw PC, Snyder JR, Harmon FA.To determine the in vitro effect of various prostaglandins (PG) and nonsteroidal anti-inflammatory drugs (NSAID) on contractile activity of the large-colon taenia of horses. Methods: 14 healthy horses. Methods: The taenia was collected from the ventral colon, cut into strips (2 X 10 mm), and mounted in a tissue bath system (20-ml capacity) that contained oxygenated Krebs buffer solution warmed to 37.5+/-0.5 C. After equilibration, incremental doses of PGE2, PGF2alpha, PGl2, flunixin meglumine, carprofen, ketoprofen, and phenylbutazone were added to the baths, and contractile activity was recor...
Marr CM.The digital storage and transfer of images coupled with the development of the Internet have revolutionized diagnostic imaging. With the press of a button, practitioners can exploit the diagnostic skills of specialists anywhere in the world and enlist their help with challenging cases. This easy transfer of images and digital data should stimulate a greater number of multicenter studies so that the sensitivity and specificity of ultrasonographic techniques can be established in larger and more meaningful cohorts of patients. There is now no doubt that we can identify a plethora of conditions o...
Kaps M, Curik I, Baban M.Heterogeneity of variance of growth traits over age is a common issue in estimating genetic parameters and is addressed in this study by selecting appropriate variance structure models for additive genetic and environmental variances. Modeling and partitioning those variances connected with analyzing small data sets were demonstrated on Lipizzan horses. The following traits were analyzed: withers height, chest girth, and cannon bone circumference. The measurements were taken at birth, and at approximately 6, 12, 24, and 36 mo of age of 660 Lipizzan horses born in Croatia between 1948 and 2000....
Röcken H, Wenz C.A unilateral malformation of the eye of a thoroughbred foal is described. The specific form of the tiny lens we named, "lenticulus". It is correlated with a maximal unchangeable mydriasis. The bulb shows physiological size. A brown-black pigmented mass inhibited (internal) inspection and examination of the middle and rear part of the eye. Special emphasis is laid on the insecure behaviour of the foal. A connection with an iridocyclochoroiditis, which was treated in the mare about a year ago, and the pathological changes in the eye of the foal is not evident.
Lakritz J, Wisner ER, Finucane T, O'Brien TR, Tyler WS, Pascoe JR, Plopper CG.Interstitial and bronchointerstitial pulmonary patterns are commonly observed in thoracic radiographs of Thoroughbreds. Prominent interstitial and bronchointerstitial pulmonary patterns are observed in clinically normal horses, and in horses with respiratory tract disease. Until recently, the relevance of these pulmonary patterns was not known. Previous studies indicated that bronchiolitis, bronchiolar epithelial hyperplasia, epithelial metaplasia, and bronchial arteriolar recruitment correlated strongly with the prominence of the interstitial and bronchointerstitial pulmonary patterns observe...