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.
Mercer JG, Munn AE, Rees HH.Both free ecdysteroids and hydrolysable polar conjugated ecdysteroids were detected in protoscoleces of Echinococcus granulosus from the equine host, and in hydatid cyst fluid from the same source. Comparisons were made of hydatid cyst fluid from E. granulosus infections of three intermediate host species: horses, sheep and humans. Ecdysone and 20-hydroxyecdysone were identified in both protoscoleces and hydatid cyst fluids by high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by capillary gas chromatography/mass spectrometry (selected ion monitoring). The fre...
Cahill JI, Goulden BE.Recent research on the muscular and nervous changes which occur in idiopathic equine laryngeal hemiplegia has indicated that many of the traditional concepts of the aetiology of this disease are erroneous. In light of the new knowledge gained, the various predispositions and possible causes of laryngeal hemiplegia are discussed, and it is suggested that the underlying mechanism of axonal damage in this neuropathy of horses may be related to abnormal energy metabolism in the axon.
Anderson RA, Gallaway WJ.The capillary tube precipitin test was used to determine the host utilization patterns of Culiseta inornata in southwestern Manitoba. Ruminant blood was identified in 83.3% and equine blood in 15.8% of 1,036 positively reacting blood-meals. Human, swine and avian blood accounted for 0.9% of these blood-meals and mixed blood-meals accounted for 1.5% of the total. Culiseta inornata preferentially fed on large mammals, and selection between cattle and horses reflected the relative abundance of these two hosts rather than a specific preference for either one.
Manohar M, Gustafson R, Nganwa D.Effects of 1.55 minimum alveolar concentration isoflurane O2 anesthesia (2.03% end-tidal isoflurane) on blood flow in the up-(nondependent) and down-(dependent) positioned skeletal muscles were studied at 60, 120, and 180 minutes in 6 healthy isocapnic ponies in right lateral recumbency on a nonpadded hardwood floor. Measurements were made, using 15-micron diameter radionuclide-labeled microspheres injected into the left ventricle, and comparisons were made with data obtained from ponies in the conscious state. Isoflurane administration caused a sharp reduction in cardiac output and systemic p...
De Lange JF, Gummow B, Turner GV, Redman AR.This is the first known isolation in the Republic of South Africa (RSA) of the serovar pomona from the organs of porcine foetuses as well as from the renal lymph nodes of slaughter pigs showing chronic nephritis. In addition, the serovar pomona was isolated from the kidneys of 87.5% of the slaughter pigs examined. The success of these isolations was attributed in part to the refining of 2 existing isolation techniques which complement each other. Using the microscopic agglutination test, serum samples taken from the same farming unit showed evidence of antibodies to the serovar pomona in 89 ou...
Bastianello SS, Nesbit JW.The pathological features of biliary atresia in a foal are described. A 4-week-old American Saddler foal was presented for autopsy following an illness characterised by clinical features indicative of hepatic failure. The significant macroscopical lesions occurred in the liver which was extremely enlarged, mottled in appearance and indurated. Bile stasis was evident. Lobular distinction was absent and on sectioning, large bile ducts were absent. A moderate ascites, hydrothorax and hydropericardium and a mild anasarca and intermuscular oedema accompanied the hepatic lesion. The diagnosis of bil...
Johnson AL.A study was conducted to evaluate the effectiveness of gonadotropin-releasing hormone (GnRH) pulse infusion to stimulate follicular development and induce ovulation in seasonally anestrous standardbred mares. Seventeen mares were selected for use in this experiment, on the basis of a previous normal reproductive history, and were housed under a photoperiod of 8L:16D beginning one week prior to the start of the experiment (second week in January). Mares were infused with 20 micrograms (n = 7) or 2 micrograms (n = 6) GnRH/h, or were subjected to photoperiod treatment only (controls, n = 4). Seru...
Hall BG, Faunce W.The genes for utilization of cellobiose are normally cryptic in both laboratory strains and natural isolates of Escherichia coli. A survey of natural isolates of E. coli reveals that functional genes for cellobiose utilization, while rare, are present. The fraction of E. coli that utilized cellobiose ranged from less than 0.01% in human fecal samples to 7% in fecal samples obtained from horses. Samples obtained from sheep, cows, dogs, and pigs contained 0.1 to 0.5% cellobiose-positive E. coli. Neither the previously identified cel genes nor the bgl genes from E. coli K-12 were expressed during...
Sedgwick AD, Lees P, Dawson J, May SA.The migration of leucocytes to sites of acute and chronic inflammation is an event of central importance to the maintenance of inflammatory processes; extravascular leucocytes are responsible for generating chemical mediators of inflammation and the phagocytosis of particulate matter. They may also be involved in the conversion of acute to chronic inflammatory lesions. Leucocytes are attracted to sites of tissue injury by a range of chemoattractants. This paper describes the development of a method for separating on Percoll gradients purified populations of equine polymorphonuclear and mononuc...
May SA, Lees P, Higgins AJ, Sedgwick AD.The cardinal signs of acute inflammation have been recognised for almost 2000 years, but it is only in the last hundred years that significant progress has been made in understanding the underlying cellular response. Our knowledge of the chemical messengers which regulate and in some cases lead to persistence of the inflammatory process is, as yet, incomplete, but it is hoped that further research at this level will lead to the development of more effective therapeutic agents.
Higgins AJ, Lees P, Sedgwick AD.Two experimental models of acute non-immune inflammation have been developed to enable studies of the biochemical composition and cellular content of exudates to be undertaken. Both are based on the creation of a mild, reproducible and reversible inflammatory reaction, which is free from uncontrolled incidental factors and which causes minimal distress to the experimental animals. The polyester sponge model involves the insertion of small polyester sponge strips soaked in sterile carrageenan solution into subcutaneous neck pouches and their serial removal. The tissue-cage model is based on the...
Lees P, Higgins AJ, Sedgwick AD, May SA.The development of reproducible models of acute inflammation in which inflammatory heat is easily quantified and from which inflammatory exudate is readily harvested has facilitated studies in the horse of the actions of steroids and non-steroidal anti-inflammatory drugs (NSAIDS). Blockade of the synthesis of eicosanoids and suppression of inflammatory heat by clinical dose rates of NSAIDS suggests a causal link between the two events and provides further evidence for a role of these compounds in acute equine inflammation. The tendency for enolic and carboxylic acids NSAIDS to accumulate in in...
Allen WE, Porter DJ.Milk and plasma samples were obtained every 48 hours from eight pony mares for 40 days after foaling. Progestogen concentrations in milk and plasma were measured using an enzyme-linked immunoassay (ELISA) and compared with radioimmunoassay of the plasma. In general the three assays showed similar trends in progestogen concentration changes but absolute values varied considerably. Difficulty could occur in interpreting the results from single samples taken at times when progestogen concentrations were either rising (ie, after ovulation) or falling. ELISA could be used on plasma obtained by allo...
The Journal of heredityMay 1, 1987
Volume 78, Issue 3 171-177 doi: 10.1093/oxfordjournals.jhered.a110351
Leone NC, Shupe JL, Gardner EJ, Millar EA, Olson AE, Phillips EC.Hereditary multiple exostosis (HME), a bone tumor first described by Virchow, has been studied over a period of 15 years on a comparative basis. The horse, an excellent biomedical model for this physically deforming multiple bone tumor in man, has been utilized in this study. The etiology, hereditary pattern, potential for malignancy and other aspects of this strange affliction need additional clarification. This in-depth study of 261 individuals from 144 families was compared with that of 55 horses bearing the HME trait, selectively bred and studied over the same period. Important information...
Martin BB, Klide AM.Fifteen horses that could not train or perform their sport at an acceptable level because of chronic back pain of 2 to 24 months' duration, and that did not obtain lasting improvement from other previous treatments, were treated with acupuncture. The treatments consisted of injection of 1 ml of sterile saline (0.9% NaCl) solution, with no preservatives, at 9 acupuncture points. The horses were treated once a week for a mean of 9 treatments. The mean number of treatments before obvious improvement was 4. After treatment, 13 of the 15 horses had apparent alleviation of their signs of pain and co...
Beaumier PM, Fenwick JD, Stevenson AJ, Weber MP, Young LM.Plasma and urinary levels of salicylic acid were examined in Standardbred mares after administration of various feeds, containing different compositions of hay. In addition, horses were administered acetylsalicylic acid orally and methyl salicylate topically. Elevated salicylic acid levels were observed in horse urine and plasma in animals fed lucerne hay. The plasma and urinary elimination of salicylic acid exhibited a diurnal pattern which was related to the type of feed and the feeding schedule. Within 24 h after oral administration of acetylsalicylic acid, plasma and urine salicylic acid l...
Summers PM, Shephard AM, Hodges JK, Kydd J, Boyle MS, Allen WR.Blastocysts were collected non-surgically from 2 Przewalski's horse and 2 Grant's zebra mares and transferred extra-specifically to domestic horse and donkey recipients. Nine Przewalski's horse embryos were transferred surgically, and 2 non-surgically, to domestic Welsh-type pony mares. After surgical transfer, 7 (77.8%) pregnancies were established and 4 foals were born. Twelve Grant's zebra embryos were transferred surgically to 5 pony and 7 domestic donkey recipients respectively and 1 non-surgically to a donkey; 3 (60%) zebra-in-horse pregnancies were established and 2 went to term. Only 2...
Arighi M, Ducharme NG, Horney FD, Livesey MA.Extensive resection (50-75%) of the large colon was performed in 12 horses. Indications for resection were: loss of viability due to large colon volvulus (seven), thromboembolic episode (three), impairment of flow of ingesta due to adhesions (one), or congenital abnormalities (one). The time required to correct the primary cause of abdominal pain and complete the resection ranged from 2.5 to 4.75 hours. Three horses had severe musculoskeletal problems postoperatively and were euthanized in the recovery stall. Four other horses were euthanized early in the postoperative period because of: furth...
Rosendal S, Lumsden JH, Viel L, Physick-Sheard PW.Neutrophils were isolated from the peripheral blood of adult equids (group 1) and were purified on a density gradient of polyvinylpyrrolidone-coated silica gel. A bactericidal assay was developed, using an equine skin isolate of Staphylococcus epidermidis as target bacterium in medium containing pooled fresh equine serum for opsonization. Significant (P less than 0.05) killing was observed after 60 or 120 minutes' incubation. Reduction in bactericidal function of blood neutrophils was not found after incubation with a virulent strain of Mycoplasma felis for 30 or 60 minutes. Similarly, the fun...
McMeniman NP, Elliott R, Groenendyk S, Dowsett KF.The extent to which cysteine synthesised by microbes within the hindgut of the horse is incorporated into plasma cysteine was estimated by an isotopic technique in two horses fed four different diets. The results showed that between 1 per cent and 6 per cent of the plasma cysteine was of microbial origin. It is argued that the maximum contribution of microbial cysteine, and presumably other amino acids of microbial origin, to the plasma pool is 12 per cent of the net supply. These data support the hypothesis that microbial amino acid synthesis within the hindgut of the horse does not significa...
Johnstone AC.Congenital vascular tumours in the skin of the legs of two horses showed histological features at biopsy which were consistent with capillary haemangioma but, at necropsy, one tumour had invaded the superficial digital flexor tendon and was therefore classified as a haemangiosarcoma.
Robertson SA.Administration of etorphine and acepromazine to horses was associated with an increase in haematocrit, blood glucose, blood lactate and plasma non-esterified fatty acids (NEFA). The rise in plasma NEFA was most striking following injection of the antagonist diprenorphine and could contribute to the production of cardiac arrhythmias. Plasma insulin was depressed at the end of surgery. These changes, plus profuse sweating, are indirect evidence of strong sympathetic stimulation. Plasma cortisol did not alter significantly due to wide individual variation. Venous blood pH fell, reflecting the ris...
Farchati H, Merlin A, Saussac M, Dornier X, Dhollande M, Garon D, Tapprest J, Sala C.Identifying and tracking equines are key activities in equine health prevention. France is one of the few European countries with an operational centralized database that records information on equines, owners, and keepers but not on the location and keeping conditions of equines. The objective of our study was to collect information on keeping habits of equines and the relative location of a wide range of equines, owners, and keepers and discuss their implication for surveillance and control of outbreak improvement. A national email survey was conducted among the 1.9% of people registered as ...
Magma (New York, N.Y.)October 4, 2019
Volume 33, Issue 2 299-307 doi: 10.1007/s10334-019-00781-z
Palfrey RM, Summers IR, Winlove CP.Quantitative magnetic resonance imaging was used to determine partition coefficients and characteristic time constants for diffusion of MRI contrast agents in disc tissue. Methods: Twenty-two excised equine intervertebral discs were exposed to a range of contrast agents: six to manganese chloride, eight to Magnevist (gadopentetate dimeglumine) and eight to Gadovist (gadobutrol), and uptake into the disc was quantified in T-weighted images. Results: Diffusion for all contrast agents was approximately 25% faster in the nucleus than in the outer annulus; disc-average time constants ranged from (2...
Wilsher S, Bowker A, Silva J, Allen WRT.A total of 127 normal placentas from Arabian mares resident in the United Arab Emirates were examined. The mean linear dimensions of the placenta were, on average, 84% of those previously recorded for the placentas of the Thoroughbred. Significant differences in the size of the allantochorion between primigravid and multiparous mares were seen only in the linear dimensions of the body portion. The pregnant horn was more commonly on the right than left side of the uterus (P = .01; 74/127; 58%). Cord attachment was primarily at the base of the two placental horns (112/127; 88%), with the remain...
Pusterla N, Vaala W, Bain FT, Chappell DE, Craig B, Schneider C, Barnett DC, Gaughan E, Papich MG.Equine protozoal myeloencephalitis (EPM) has remained a devastating neurological disease of the Americas, especially in young performance horses. Prophylactic treatment strategies with diclazuril have shown to reduce seroprevalence and titer levels to Sarcocystis neurona in healthy horses continuously exposed to the apicomplexan parasite. The goal of this study was to determine if the FDA-labeled dose of 1 mg/kg of 1.56% diclazuril (Protazil) given once weekly to healthy adult horses would achieve steady-state concentrations in plasma known to be inhibitory to S. neurona in cell culture. Five ...
Moghtaderi M, Farjadian S, Hosseini Z, Raayat A.The aim of this study has been to investigate the frequency of sensitization to horse allergens and clinical symptoms in horse riders. Methods: A total of 42 horse riders and 50 healthy individuals were examined by means of skin prick tests for a panel of horse and common animal allergens, and pulmonary function tests were done by spirometry. Results: The rate of sensitization to horse allergens was 31% as proven by the skin prick test in horse riders whereas horse sensitization was not seen in the control group. Occupational allergy symptoms were reported by 19 horse riders. Two horse riders ...
Whitehead AE, Whitty J, Scott M, Léguillette R.A gelding was diagnosed with dysphagia and left guttural pouch mycosis. Treatments included topical antifungal drugs, systemic voriconazole, and balloon occlusion of the internal carotid artery. Ongoing dysphagia of neurological origin necessitated extra-oral feeding through an esophagostomy tube. Complementary case management included acupuncture. Clinical remission occurred over 10 weeks. Dysphagie réversible secondaire à une mycose de la poche gutturale chez un hongre traité médicalement avec du voriconazole et chirurgicalement par l’occlusion de la carotide et l’œsophagostomie. Un...
Jalim SL, McKinnon AO, Russell TM.A Monteggia fracture is a humero-radial luxation combined with a fracture of the ulna. It is a rare injury, infrequently reported in the horse. This case report describes the surgical repair of such a fracture in a 4-month-old filly.
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Koshy SA.It is important to remember that performance-enhancing agents such as non-peptide growth hormone secretagogues present a significant risk of abuse. Ibutamoren (MK-0677) is a potent, long-acting, selective non-peptide growth hormone secretagogue that can be taken orally. Methods: This study examines ibutamoren and its metabolites in thoroughbred horses after oral administration. Liquid chromatography/high-resolution mass spectrometry was used to determine the probable structures of the detected metabolites. Results: In this study, 22 metabolites of ibutamoren were identified (17 phase I and 5 p...
Forsyth SF, Lopez-Villalobos N, Rogers CW.To assess the stability of creatine kinase (CK) activity in plasma collected from healthy foals and frozen at -20 degrees C for up to 12 weeks. Methods: Samples of venous blood drawn from 25 foals were analysed for CK activity soon after collection, and again after 1 and 12 weeks of freezing at -20 degrees C. Results: CK activity decreased (p<0.001) between Week 0 and Week 1 and between Week 0 and Week 12. Conclusions: Decreases in CK activity were statistically significant but clinically insignificant.
Ortillés Á, Sanmartí J, Ríos J, Armengou L, Peña MT, Leiva M.To evaluate the effect of topical cyclopentolate hydrochloride (CH) on quantitative pupillometric readings (PR), tear production (TP), and intraocular pressure (IOP) in healthy horses. Methods: Fourteen client-owned horses. Methods: In a two-phase design study, each animal received 1% CH ophthalmic solution in the left eye [treated] and 0.9% NaCl in the right eye [control] (0.2 mL each). In the first phase (n = 7), TP, IOP, and PR assessment was performed by Schirmer tear test I, rebound tonometry and static pupillometry, at 1, 8, 24, 48, 72, 96, 120, 148, 172, and 196-hours post-instillati...
Erridge ME, Cox AL, Dixon PM.Peripheral caries of equine cheek teeth is a poorly described disorder and, in particular little is known of its histopathology. Histological examinations of decalcified sections of 21 equine peripheral caries-affected cheek teeth showed two different patterns of cemental lesions; including progressive enlargement of focal, flask-like lesions leading to breakdown of the adjacent cementum, and secondly; a more generalized flaking-off of thin layers of under-run, surface cementum. A thick layer of plaque and food material usually lay on the surface of affected cementum and also within cemental d...
Keller H, Hashem A.In a study in the horse, the disposition, the pharmacokinetic parameters and the absorption rates of 3 formulations of phenylbutazone (injection solution, powder and paste suspension) have been determined. After i.v. injection, the half-life time of phenylbutazone has been determined to be 6.6-6.7 h. After oral administration, the absorption of phenylbutazone was found to be faster after administration via stomach tube than after direct application into the mouth. The absorption rat constant of the paste suspension was found to be higher than that of the powder (1.797-2.304 h-1 vs. 0.656-1.197...
Taylor BM, Chaffin MK, Hoffmann AR, Edwards JF, Arenas-Gamboa AM.Prolonged exposure to water, known as immersion foot syndrome in humans, is a phenomenon first described in soldiers during World War I and characterized by dermal ischemic necrosis. In this report, we describe the pathologic findings of a condition resembling immersion foot syndrome in 5 horses and 1 donkey with prolonged floodwater exposure during Hurricane Harvey. At necropsy, all animals had dermal defects ventral to a sharply demarcated "water line" along the lateral trunk. In 5 animals, histologic examination revealed moderate to severe perivascular dermatitis with vasculitis and coagula...
Stanley S, Wood T, Goodman JP, Henry PA, Woods WE, Chang SL, Tai HH, Watt D, Kwiatkowski S, Blake JW.We have raised antibodies and developed one-step enzyme-linked immunosorbent assays (ELISA) for the diuretics ethacrynic acid and bumetanide as part of a panel of pre- and post-race tests for high potency drugs in racing horses. These ELISA tests are rapid (completed within one hour), sensitive, and can be read by eye. The ELISA detects ethacrynic acid at a drug concentration for half-maximal inhibition (I-50) of about 2.5 ng/mL for the parent drug. After dosing horses intravenously with 5 mg ethacrynic acid per horse, the parent drug or its metabolites are detectable in urine for at least 8 h...
Doran G, Hughes K, Rendle D, Edwards S.Pergolide is used to treat pituitary pars intermedia dysfunction (equine Cushing's Disease), a neurodegenerative condition associated with loss of dopaminergic inhibition of the pituitary in horses. After oral administration, only low concentrations of the drug are achieved in plasma, making drug detection and quantification difficult. While direct analysis of plasma using sensitive MS/MS techniques is possible, dirty plasma samples and mobile phase buffers can cause instrumentation to become rapidly incapacitated. A method using LC with fluorescence detection was developed for pergolide analy...
Wanstrath MA, Bauck AG, Smith AD, Freeman DE.To assess the safety and efficacy of a method for digitally enlarging the caudal aspect of the epiploic foramen (EF). Methods: Healthy horses and clinical cases of EF entrapment (EFE). Methods: Fourteen healthy horses and three clinical cases. Methods: Through a ventral midline celiotomy under general anesthesia, the EF was enlarged by digital separation of the caudal attachments of the caudate lobe of the liver from right dorsal colon, right kidney, gastropancreatic fold, and pancreas. Healthy horses were euthanized under anesthesia, and the enlarged EF was measured at necropsy. Results: The ...
Hollenbach E, Robert MP, le Roux C, Smit Y.If the number of events alone is considered, endurance riding is the fastest growing and the second-most popular Fédération Equestre Internationale (FEI) discipline. Lameness is the most common cause of elimination from endurance races worldwide. To the authors' knowledge, no studies have been published investigating the prevalence of radiographic changes in the forelimb digits and metacarpophalangeal joints (MCP) of endurance racehorses in South Africa. Unassigned: Investigate the prevalence of radiographic changes in the forelimb digits and MCP joints of South African endurance racehorses....
Watson ED, Zanecosky HG.Fluid was aspirated from the preovulatory follicles of mares before and 12, 24 and 36 h after intravenous administration of hCG. Follicular fluid significantly (P less than 0.001) reduced lymphocyte blastogenesis in vitro and, at a dilution of 1:100, fluid collected at 36 h after administration of hCG was significantly more suppressive (P less than 0.01) than fluid collected before 36 h. Suppression of blastogenesis was reduced by extracting the follicular fluid with ether or by charcoal treatment (P less than 0.01) or by heating at 56 degrees C for 30 min (P less than 0.05). Preincubation of ...