Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
McKinnon AO, Squires EL, Harrison LA, Blach EL, Shideler RK.During breeding of mares, ultrasonographic detection of uterine fluid accumulations in the first postpartum ovulatory period was associated with significantly decreased pregnancy rates, when compared with rates in control mares (P less than 0.005). The previously gravid uterine horn was recognized as the larger horn, when assessed for size by ultrasonography, for a mean of 21 days (range, 15 to 25 days) after parturition. On the basis of similar measurements obtained during 3 ultrasonographic scans (5-day period), uterine involution was determined to be completed in a mean of 23 days (range, 1...
Livesey MA, Arighi M, Ducharme NG, Horney FD, Hurtig MB.Incarceration of the large colon by the suspensory ligament of the spleen was diagnosed and surgically corrected on exploratory celiotomy in 76 horses exhibiting abdominal pain. The condition was diagnosed most frequently during the winter months in mature males of mean age 4.7 years. Clinical signs progressed slowly and included mild to moderate abdominal pain and distension with moderate tachycardia. The mean duration of colic prior to surgical intervention was 20.7 hours. The mild nature of the colic, the findings on palpation per rectum, and the continued passage of feces in 40% of horses,...
Kasman LH, Hughes JP, Stabenfeldt GH, Starr MD, Lasley BL.Serum and urinary estrone sulfate concentrations were determined in 7 pregnant mares before and after prostaglandin-induced abortion (n = 4) or surgical removal of the fetus (n = 3) to determine the source of estrogen during early pregnancy (gestation days [GD] 44 to 89). Estrone sulfate concentrations also were determined in serum samples (stored frozen for 2 years) from 3 mares that had been ovariectomized between GD 51 and 58. Estrone sulfate concentrations decreased in serum and urine after expulsion or removal of the fetus (urinary patterns were more definitive than were patterns for seru...
Platt H.A retrospective study was carried out on post-mortem and biopsy tissue samples from 26 horses with non-alimentary lymphoma. On the basis of their histopathology and cytology, the cases were grouped into several categories: (1) Lymphoblastic lymphomas (6 cases) and primary lymphoblastic leukaemia (2 cases). (2) Histiolymphocytic lymphomas involving the skin (6 cases) or lymph nodes (3 cases). (3) Lymphomas showing follicular development (4 cases). (4) Plasmacytic lymphomas (4 cases). (5) Lymphocytic lymphoma (1 case). Most affected horses were middle-aged or old but lymphoblastic neoplasms tend...
Stover SM, Steffey EP, Dybdal NO, Franti CE.Five horses were anesthetized similarly by use of xylazine, guaifenesin, thiamylal sodium, and halothane in oxygen on 3 consecutive days, and minor surgical procedures were performed. For 1 to 10 days after the last anesthetic exposure, clinical, hematologic, and serum biochemical features were monitored, and after necropsy, histologic examination of major organ tissues was performed. Predominant hematologic changes from base-line values included leukocytosis (maximal at 27 hours, 10,500 +/- 1,750 cells/microliter), neutrophilia (maximal at 51 hours, 7,485 +/- 1,719 cells/microliter), and lymp...
Horvath CJ, Ames TR, Metz AL, Larson VL.Pituitary-dependent hyperadrenocorticism was diagnosed in a 14-year-old Arabian mare with chronic weight loss, hirsutism, polyuria, and polydipsia. The mare had a stress leukogram, glucosuria, and consistent hyperglycemia. Plasma glucose concentrations were resistant to suppression by insulin. Plasma cortisol concentrations were within normal limits, but did not respond to dexamethasone suppression and had an exaggerated response to ACTH stimulation. At necropsy, a chromophobe adenoma of the pars intermedia of the pituitary gland was found. The zona fasciculata of the adrenal cortex and the pa...
Bridges CG, Ledger N, Edington N.Ponies, without evidence of previous exposure to Equine herpes virus-1 (EHV-1), were experimentally infected with EHV-1 subtype 2 and investigated for lymphocyte transformation to virus-infected cell polypeptides, as shown by separation with gel electrophoresis. Animals made significant responses to Western blot fractions that corresponded to molecular weights of approximately 30,000, 40,000-45,000, 60,000-65,000, 80,000-95,000 and 100,000-140,000 MW. These molecular weight ranges correlated with the positions of major EHV-1 subtype 2 glycoproteins that were found at migration distances approx...
Gibbs PG, Potter GD, Schelling GT, Kreider JL, Boyd CL.Mature ponies fitted with permanent ileal cannulas were used in a 3 X 3 Latin square experiment to quantify prececal, postileal and total tract digestion of hay protein. Coastal Bermuda grass (CB), containing 11.7% crude protein, and two qualities of alfalfa, containing 15.0% (low-protein alfalfa; LA) and 18.1% (high-protein alfalfa; HA) crude protein, were fed in coarsely chopped form at 2% of body weight daily. Total tract apparent digestibility of the N in HA (73.8%) was higher than that in CB (57.0%; P less than .05) and was slightly higher than that in LA (66.1%; P less than .10). Nitroge...
Hayden DW, Johnson KH, Wolf CB, Westermark P.Systemic amyloidosis involving the digestive tract is described in an 11-year-old Morgan stallion. The disease was characterized clinically by weight loss, ptyalism, anaemia, persistent mature neutrophilia, hypoalbuminaemia and hypergammaglobulinaemia. The D-xylose absorption test indicated malabsorption. Necropsy revealed oral, oesophageal and gastric ulcers and reddened segments of small bowel mucosa with scant haemorrhages. Microscopically, amyloid deposits were found throughout all tissue layers of the digestive tract, except the serosa. Deposits of amyloid were most apparent in the small ...
Kirkpatrick CE, Saik JE.Ciliated protozoa of several morphological types were found in the colonic tissue of 8 horses, mostly immature Standardbreds. Most of the protozoa observed appeared similar to those normally found as commensals in the equine large intestinal lumen. In all cases, organisms were located in the lamina propria; organisms were also found in the submucosa of 2 horses. The association of colonic disease with the presence of intramural ciliates was unclear.
Stull CL, Rodiek AV.Two experiments were conducted to determine the response of blood glucose, insulin and cortisol levels to four common equine diets. Experiment 1 was designed to determine the diurnal variation of glucose and two glucoregulatory hormones, insulin and cortisol, in four fasting geldings. No diurnal variation was observed in either glucose or insulin levels during the 24-h sampling period. However, cortisol levels did exhibit a circadian rhythm, with elevated values observed in the morning and low values in the evening. Experiment 2 investigated the response of glucose, insulin, cortisol and selec...
Dean PW, Robertson JT.A urachal remnant, causing pollakiuria and dysuria, was diagnosed by rectal palpation of a urinary bladder adhesion and endoscopic visualization of a urinary bladder diverticulum. Surgical excision of the remnant resulted in relief of abnormal micturition, but the filly was euthanatized 9 months after surgery because of a chronic ventral midline incisional infection. Pollakiuria and dysuria associated with urachal abscessation occur most commonly in calves. This report documents the syndrome in a horse.
Wyatt CR, Davis WC, McGuire TC, Perryman LE.Six monoclonal antibodies reacting with equine T lymphocytes at different stages of maturation were selected from antibodies produced against lymphoid cell preparations. EqT12 and EqT13 antibodies identified subsets of cortical thymocytes with high terminal deoxynucleotidyltransferase (TdT) activity and no phytolectin responsiveness. EqT12+ thymocytes were scattered throughout the cortex while EqT13+ thymocytes were located in the subcapsular cortex. EqT12 bound to small numbers of bone marrow cells, splenocytes, and circulating lymphoid cells, but not to mature T lymphocytes. EqT13 bound to v...
Koblik PD, O'Brien TR, Coyne CP.The effect of dorsopalmar projection obliquity on calculation of distal phalangeal rotation (DPR) angle was determined in 8 feet obtained from 5 horses that had been euthanatized because of laminitis. A true lateromedial view of each foot served as a reference, with additional views taken at 5, 10, 15, and 20 degrees of x-ray tube head rotation in both a dorsal and in a palmar direction. Projection obliquity resulted in consistent underestimation of DPR angle. Where projection obliquity exceeded 10 degrees, there were significant (P less than 0.05) differences in DPR angle. The magnitude of un...
McCarthy RN, Hutchins DR.A retrospective analysis of 74 cases that underwent surgery for colic was undertaken to determine short and long term survival rates and the incidence of post-operative complications. In 28 cases colic was related to small intestinal lesions and in 46 cases to large intestinal lesions. Pre-operative packed cell volume and heart rate were found to be inversely related to short-term survival. Twenty-five horses (34%) recovered from surgery and were discharged. Of 18 of these cases with available histories, 6 subsequently had one or more episodes of colic since surgery of which 5 eventually died ...
Firth EC, Schamhardt HC, Hartman W.Two to 7 days after birth, 9 foals were anesthetized, and strain gauges were applied to lateral and medial aspects of the third metacarpal bone of the left forelimb. In 5 of these foals, strain gauges also were applied to the radius of the left forelimb. Four to 6 days later, foals were walked (5 sets of 10 to 20 strides), and compressive and tensile strains in the bone beneath strain gauges were recorded on paper and diskette. After recording base-line data, a wedge was fitted to the hoof of the limb with the strain gauges, in such a way that the lateral bearing surface was raised, and strain...
Songer JG, Beckenbach K, Marshall MM, Olson GB, Kelley L.Isolates (n = 94) of Corynebacterium pseudotuberculosis were obtained from sheep, goats, horses, and cattle from various parts of the world. The isolates were characterized biochemically and by restriction endonuclease analysis of DNA. We found near homogeneity in the ability of isolates to ferment carbohydrates and to produce urease. All isolates produced phospholipase D and catalase. The ability of isolates from horses to reduce nitrate, the inability of isolates from sheep and goats to do so, and the correlation of this characteristic with results of restriction endonuclease analyses confir...
Kloppe LH, Varner DD, Elmore RG, Bretzlaff KN, Shull JW.A breeding trial was conducted to evaluate the effect of insemination timing on the fertility of mares bred with frozen/thawed equine semen. One stallion and 60 reproductively sound, estrous-synchronized mares were included in the study. Mares were assigned to one of three groups (n = 20): 1) insemination with fresh semen every other day during estrus from detection of a 35-mm follicle until ovulation, 2) insemination with frozen/thawed semen every day during estrus from detection of a 35-mm follicle until ovulation or 3) insemination with frozen/thawed semen once, within 6 h after ovulation. ...
Murray MJ, Ball MM, Parker GA.A 3-month-old foal with a history of persistent fever and leukocytosis was found to have pneumonia, ulceration of the squamous portion of the stomach, and dilatation of the distal portion of the esophagus. The foal was euthanatized and necropsied. The distal portion of the esophagus was severely dilated, and there was severe ulceration and mural thickening of the stomach at the cardia. Because of the severe gastric ulceration and mural thickening, the gastroesophageal junction was fixed in an open position, permitting gastroesophageal reflux. The megaesophagus and pneumonia were considered to ...
Sundquist B, Lövgren K, Morein B.A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Schaller J, Rickli EE.The N-terminal amino acid sequence of equine, ovine, canine, goat and rabbit plasminogen were determined and compared with those already known of the human, bovine, porcine and feline molecule. Furthermore, the kringle 4 domains of equine, ovine, canine and goat plasminogen, prepared by limited cleavage with elastase, were sequenced and compared with the known species of human, bovine, porcine and chicken plasminogen. Homology with the human kringle 4 ranges between 73% (chicken) and 90% (bovine). Comparison of sequences, fragmentation patterns with elastase and adsorption on lysine-Bio-Gel su...
Yang JM, Woods WE, Weckman TJ, Wood TW, Chang SL, Blake JW, Tobin T.1. Drug administration studies using diisopropylamine dichloroacetate (DADA) and diisopropylamine (DIPA) were conducted in Thoroughbred and Standardbred horses to assess physiological effects and develop detection methods. 2. Four horses received 0.08 mg DADA/kg body wt and showed no changes in heart and respiratory rates or body temperature as measured over a 1-hr period after administration. A transient diuretic effect was found to occur in 2 mares dosed with 0.80 mg DADA/kg body wt. 3. A qualitative detection method using thin-layer chromatography was developed to detect DIPA, the major met...
Jones I, Madej A.Microtitre plates were coated with antiserum against oestradiol-17 beta-6-(O-carboxymethyl)-oxime bovine serum albumin raised in sheep. The plasma samples (0.2-1.0 ml) were extracted with peroxide-free diethyl ether prepared daily by treatment with Al2O3. The enzyme conjugate was prepared by coupling oestradiol-17 beta-6-(O-carboxymethyl)-oxime to horse-radish peroxidase. The conjugate was chromatographed on a Sephadex G-25 column. The standard curve ranged from 0.37 to 18.40 fmol/well of oestradiol-17 beta. The amount of oestradiol-17 beta causing a 50% reduction of maximum binding was 4.4 fm...
Tai CL, Wang C, Weckman TJ, Popot MA, Woods WE, Yang JM, Blake J, Tai HH, Tobin T.To improve the sensitivity and specificity of screening for etorphine in horses, an 125I-labeled etorphine analog was synthesized and an antibody to etorphine was raised in rabbits. A radioimmunoassay (RIA) for etorphine was developed, using these reagents. Bound and free 125I-labeled etorphine was separated by a double-antibody method that reduced interference from materials associated with equine urine. The 125I-labeled etorphine binding was rarely greater than 250 pg of background etorphine equivalents/ml in raw urine and was 100 pg/ml in hydrolyzed urine. The 125I-RIA was capable of detect...
Crijns CP, Van Bree HJ, Broeckx BJG, Schauvliege S, Van Loon G, Martens A, Vanderperren K, Dingemanse WB, Gielen IM.The objective of this study was to examine the influence of the size, age and sex of the horse on the size of the pituitary gland and determine the possibility of using the pituitary gland height-to-brain area ratio (P:B ratio) to allow comparison of different sized and aged horses. Thirty-two horses without pituitary pars inter-media dysfunction that underwent a contrast-enhanced computed tomographic (CT) examination were included in a cross-sectional study. On the CT images, the pituitary gland height was measured and the P:B ratio was calculated. These measurements were correlated to the si...
Dart AJ, Snyder JR, Harmon FA.The microvascular circulation of the descending colon was studied in 5 adult horses, using microangiography and light microscopy combined with gross studies and scanning electron microscopy of vascular replicas. After heparinization, horses were euthanatized, and 3 segments of the descending colon and its mesentery containing 1 vascular arcade were removed from each horse. The fecal balls were gently massaged from the lumen, and the blood was flushed free of the circulation with isotonic NaCl. In 5 segments, the vascular system was injected with a modified radiopaque medium and evaluated radio...
Zorigt T, Furuta Y, Simbotwe M, Ochi A, Tsujinouchi M, Shawa M, Shimizu T, Isoda N, Enkhtuya J, Higashi H.Anthrax is a zoonotic disease caused by the gram-positive spore-forming bacterium Bacillus anthracis. Detecting naturally acquired antibodies against anthrax sublethal exposure in animals is essential for anthrax surveillance and effective control measures. Serological assays based on protective antigen (PA) of B. anthracis are mainly used for anthrax surveillance and vaccine evaluation. Although the assay is reliable, it is challenging to distinguish the naturally acquired antibodies from vaccine-induced immunity in animals because PA is cross-reactive to both antibodies. Although additional ...
Lusi CM, Davies HMS.Passive dynamics is an aspect of locomotion which is entirely dependent on the mechanical configuration and linkages of adjacent body segments. Tension distribution along mechanical linkages enables the execution of movement patterns with reduced need for complex neurological pathways and may play a role in reestablishing postural stability following external disturbances. Here we demonstrate a uni-directional mechanical relationship between the equine forelimb, head and neck, which may have implications for balance and forelimb loading in the horse. These observations suggest that forelimb, h...
Guo X, Pei J, Chu M, Wu X, Bao P, Ding X, Liang C, Yan P.The complete mitochondrial genome of Hequ horse was determined in this study. The mitogenome is 16 656 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a D-loop region. The overall base composition of the H-strand is 32.20% for A, 28.55% for C, 13.38% for G and 25.86% for T. Tree constructed using MEGA 6 with Maximum-likelihood (ML) methods demonstrated that Hequ horse was clustered in subfamily Equidae.
Ross DH, Heird C, Byrd JW, Beauchemin V, Kiess W.The safety of a feed-thru pellet formulation containing the insect growth regulator diflubenzuron (0.24%) for control of manure-breeding flies (Musca domestica L. and Stomoxys calcitrans L.) in horses was evaluated. Pellets were administered orally at 0, 1, 3, and 5 times the clinical dosage (0.12 to 0.20 mg/kg) on a daily basis for 31 consecutive days. Variables examined included daily clinical observations, hematology, coagulation, serum chemistry, acetylcholinesterase inhibition, body weights, and physical examinations. Horses remained healthy throughout the study, and no adverse reactions ...
Atai T, Ozmaie S, Anoushepour A.This research was performed to compare the effects of prednisolone and fluorometholone on intraocular pressure (IOP) and Schirmer tear test (STT) in the normal equine eye. Sixteen normal mares aged between 6 and 10 years were used for this study. Horses were randomly assigned to two groups. Eight horses in the first group received 0.2 mL of topical 1% prednisolone in one eye and the contralateral eye was used as control (0.2 mL of saline was instilled). The second group received 0.2 mL of 0.1% fluorometholone in a randomly selected eye and the contralateral eye served as control and received 0...
Proudman C, Pinchbeck G, Clegg P, French N.As in other competitive sports, the famous Grand National steeplechase, which is held at Aintree in the United Kingdom and is watched by 600 million people worldwide, sometimes results in injury. By analysing data from the past 15 Grand National races (consisting of 560 starts by horses), we are able to identify several factors that are significantly associated with failure to complete the race: no previous experience of the course and its unique obstacles, unfavourable ground conditions (too soft or too hard), a large number of runners, and the length of the odds ('starting price'). We also f...
Dacre KJ, McAleese SM, Knight P, McGorum BC, Pemberton AD.Mast cell mediators are believed to play a central role in inflammatory lung disorders such as human allergic and occupational asthma. Equine heaves is characterized by reversible neutrophilic airway inflammation and airway obstruction, primarily due to bronchospasm and mucus hypersecretion, following exposure of susceptible horses to organic stable dusts. As such, heaves shares many similarities with human occupational dust-induced asthma and therefore it is proposed that mast cells may also be implicated in the pathogenesis of heaves. Tryptase, a mast cell-specific proteinase, can be used as...
Kempson SA, Campbell EH.The permeability barrier in the dorsal wall of the equine hoof capsule was studied by means of horseradish peroxidase (HRP) in 0.9 N saline solution as a water soluble tracer. Section were treated with 3'3'-diaminobenzidine tetrachloride (DAB) and before dissection the quality of the horn of feet from 10 horses was assessed and given a subjective grade as either good or poor. Blocks of tissue from each horse were left in either an oven at 60 degrees C or in water for 2 weeks before treatment in HRP, sectioning and DAB solution. Regions observed were i) outer surface, ii) outermost layers of th...
Greydanus-van der Putten SW, Klein WR, Blankenstein B, de Hoog GS, Koeman J.A 9-year old male Arabian horse was referred to the Department of Large Animal Surgery of the University of Utrecht because of multiple nodules on the inner side of the right hind leg. The nodules seemed to follow a cutaneolymphatic pattern. Histopathology of a nodule showed a granulomatous inflammation with the presence of multinucleated giant cells. In PAS- and Grocott-stained sections, spheroid yeast-like organisms with some budding were found throughout the tissue. A preliminary diagnosis of sporotrichosis was made. A fresh nodule was cultured and the presence of Sporothrix c.f. schenckii ...