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.
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...
Buonanno AM, Carlson GP, Kantrowitz B.Portosystemic shunt was diagnosed in a 6-month-old Quarter Horse filly with acute onset of apparent blindness and a 3-month history of depression, lethargy, and ataxia. Clinicopathologic test results indicated slightly high gamma-glutamyl transpeptidase activity and serum total bilirubin concentration. Sulfobromophthalein half time was prolonged, and plasma ammonia and serum bile acid concentrations were high as well. Histopathologic findings of percutaneous liver biopsy included widespread hepatocyte atrophy and numerous prominent small arterioles in the area of the portal triad. On the basis...
Mendoza L, Alfaro AA, Villalobos J.A 5-year-old, female saddle horse developed a tumoral mass anterolaterally on the metacarpal region of its right front leg. Histopathological study showed hyaline, aseptate, broad hyphae in the sequestered coral-like necrotic masses. Radiographs revealed an extensive osteomyelitis with disorganized bone proliferation of the metacarpal bones, as well as exostosis of the distal radius and the proximal and distal row of carpal bones. The etiologic agent was detected histologically, isolated in culture and identified as Pythium insidiosum. Serological tests were positive. Immunotherapy was applied...
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.
Freeman DW, Potter GD, Schelling GT, Kreider JL.Nitrogen metabolism was measured in five mature geldings performing varying levels of work that simulated race training. Following an initial maintenance period without forced exercise, workload was increased in succeeding 18-d periods by doubling the distance the horses were galloped in each period from period 2 through 4. A 4-d N balance experiment was conducted at the end of each 18-d period. The maximum distance galloped daily, which was in period 4, was repeated in period 5. Then, workloads were decreased through period 7. Nitrogen balance was determined in two additional periods, 8 and 9...
Nixon AJ, Adams RM, Teigland MB.Bilateral subchondral cystic lesions of the femoral head in a horse resulted in lameness. The lesions had resulted in degenerative disease in the left coxofemoral joint. The cause of lameness was confirmed by use of intra-articular anesthesia, joint fluid analysis, and radiography. Subchondral cystic lesions involving the femoral head should be considered in the differential diagnosis of equine lameness localized in the upper portion of the hind limb.
Palmer JE, Whitlock RH, Benson CE.Equine ehrlichial colitis was experimentally induced in 18 ponies, using Ehrlichia risticii-infected blood. Four ponies (group 1) were treated with oxytetracycline (6.6 mg/kg of body weight, IV, q 12 h), beginning 14 hours before inoculation and continuing for 5 days after inoculation. Four additional ponies (group 2) were treated similarly for 10 days after inoculation. The remaining 10 ponies were used as nontreated, infected controls. Clinical disease was delayed in 3 group-1 ponies and in 4 group-2 ponies. Protective immunity developed in the remaining pony that did not develop clinical di...
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.
Markel MD, Dreyfuss DJ, Meagher DM.A study was designed to evaluate 2 colopexy techniques (A and B) in 8 clinically normal horses to determine which technique would prevent recurrence of large-colon displacement and/or volvulus. For technique A, 35 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. For technique B, the medial free band of the left ventral colon was sutured to the medial free band of the right ventral colon, and 8 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. ...
Belknap J, Arden W, Yamini B.A 2-month-old Standard-bred colt with signs of abdominal pain and large scrotum was found to have septic periorchitis involving the right testis. Surgical exploration of the abdomen and scrotum was performed; the colt was then castrated. Actinobacillus equuli was isolated from specimens obtained at surgery. The colt was treated with broad-spectrum antibiotics and flunixin meglumine after surgery, and fully recovered. The clinical signs of periorchitis in the colt were similar to an inguinal/scrotal hernia.
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...
Markel MD, Wheat JD, Jones K.The medical records of 10 horses with invasive neoplasms of the penis, prepuce, and/or superficial inguinal lymph nodes in which treatment involved en bloc resection and penile retroversion were reviewed. All were geldings and ranged in age from 12 to 25 years (mean, 19 years). Evaluation of biopsy specimens obtained before surgery confirmed lymphosarcoma in 1 horse and squamous cell carcinoma in 9 horses. Typical history included swelling, ulceration, and abscessation of the penis and prepuce and large superficial inguinal lymph nodes. Complications after surgery included dehiscence of the ur...
Wright JA, Hodson NP.Lesions in a wide range of cranial nuclei are described in 11 horses with grass sickness. Similar changes were seen in one horse with laminitis, but not in control animals. It is suggested that such lesions are non-specific in nature.
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...
Bohanon TC.An 8-cm compressed mass of dry cracked corn was found obstructing the duodenum of a horse with signs of colic. The mass was manipulated aborally and removed through jejunal enterotomy. The horse recovered and the impaction did not recur.
Ross MW, Stephens PR, Reimer JM.A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosi...
Parry BW, Anderson GA.Seventeen horses were used to determine the variances associated with blood pressure cuff application (Sp2) and with other inherent errors (So2). Systolic pressure values had Sp2 = 3.9 mmHg and So2 = 5.6 mmHg, while diastolic pressure values had Sp2 = 1.1 mmHg and So2 = 4.4 mmHg. Thus, to be considered different, two blood pressure means (in mmHg), each derived from three readings, had to differ by at least 3.9 for systolic pressure and 3.4 for diastolic pressure when all readings were made without cuff displacement; 6.8 for systolic pressure and 4.6 for diastolic pressure when the cuff was re...
Jeffcott LB, Rossdale PD.The current knowledge of the clinical signs, epidemiology and pathogenesis of abortion due to the equid herpesvirus (EHV 1) is reviewed. The relationship between the respiratory and abortigenic forms of the disease is discussed as well as the low incidence of virus abortion in the UK compared to some other parts of the world. Some practical aspects of the disease as they affect stud management are considered including methods of diagnosis, prophylaxis and the necessary action to be taken to prevent spread of infection.
Emmerich IU.In 2011, three newly developed active pharmaceutical ingredients for horses and food producing animals were released on the German market for veterinary drug products. Two of these new products represent different drug classes of antibiotics, the polypeptide antibiotic Bacitracin (Bacivet™) and the macrolide antibiotic Clorsulon (Levatum®). The third product represents an anticestodal antiparasitic (Tildipirosin, Zuprevo®). Furthermore, three established veterinary active pharmaceutical ingredients were modified to allow their application for additional species. Thus the nonsteroidal anti-...
Tainturier D, Picavet DP, Badin De Montjoye T, Guaguere J, Tailliar S, Dabernat HJ, Ferney J.Serological response of pony mares to contagious equine metritis is studied comparing three techniques: slow agglutination, complement fixation and indirect immunofluorescence. Sera were taken from pony mares vaccinated with a heat inactivated suspension of Haemophilus equigenitalis, from experimentally-infected pony mares and from healthy horses. All three reactions detected antibodies in vaccinated and infected animals. The highest titers are observed with vaccinated mares. Titers are low in infected animals. Antibodies detected by indirect immunofluorescence appeared sooner and persisted lo...
Edwards GB.Results of the clinical and radiographic examination of 8 lame horses with tarsal sheath distension are described. In chronic cases pathological exostoses were identified radiographically in the sustentaculum tali and were demonstrated at post mortem in 4 of the horses which were destroyed. The prognosis and the feasibility of treatment are discussed in the light of these changes and the associated damage found at post mortem in the deep flexor tendon and its sheath. Trauma to the hock was known to have occurred in half the cases and was suspected in the others.
Granello ME, Weatherall KM, Lutter JD, Beard WL. The aim of this study was to compare the deflection distance, deflection angle and pre-loading sub-bandage pressure of a transverse, mid-metacarpal fracture in an equine cadaver limb when loaded in bending while stabilized with either a Robert Jones Bandage (RJB) or a single-stack bandage (SS), each containing two orthogonal splints. Methods: In an ex vivo experimental study, forelimb pairs from eight horses were collected, and one forelimb from each pair was assigned to either the SS or RJB groups. A transverse osteotomy was performed at the midpoint of the metacarpus. After bandaging, ...
Brostroöm H, Paulie S, Perlmann P.To characterise the expression of surface antigens on equine sarcoid cells compared to normal equine fibroblasts, immune sera were produced in rabbits against transformed cells of a virus-containing sarcoid cell line (Mc-1) and normal dermal fibroblasts, respectively. The specificities of the sera were analysed by antibody-dependent cellular cytotoxicity against 51Cr-labelled target cells using human lymphocytes as effector cells. Anti-Mc-1 antiserum induced strong cytotoxicity against transformed cells of two sarcoid cell lines (Mc-1 and Bay Mc-1), whereas the cytotoxicity against transformed...
Baska-Vincze B, Baska F, Szenci O.In the equine practice, attempts have been made to examine the fetus in the second and third trimester of pregnancy but all of the available methods have limitations. Until now, transabdominal ultrasonography has been regarded as the most informative examination. This method allows us to measure fetal heart rate, fetal activity as well as the quality and quantity of the fetal fluids. A modified biophysical profile for horses was used by several researchers in the USA from the 1990s as a gold standard. However, it is not sensitive enough and, in the authors' experience, professionals can face d...
Pascoe RR, Pascoe DR, Wilson MC.Between 1982 and 1985, 1015 mares were evaluated using the following parameters: age, mare status (maiden, barren, lactating), Caslick index, Caslick operation, ovarian cycle, ovarian and follicular size, treatments (hCG and intrauterine infusions), number of ovulations after mating (184 mares), number of conceptuses present, dimensions of embryonic vesicles, and pregnancy status 45 days after mating. Mares were examined ultrasonographically between Days 12 and 25 to detect the presence of embryonic vesicles and measure the dimensions of each vesicle. The data were analysed by a stepwise logis...
Donadeu FX, Ginther OJ.The changes in circulating concentrations of FSH, LH, estradiol, and total inhibin associated with the beginning of follicle diameter deviation were compared among the last anovulatory follicular wave of the year and the first and second ovulatory waves in pony mares ( n=7 ). Follicle diameters and circulating hormone concentrations for each wave were normalized to the observed beginning of deviation (Day 0). Follicle deviation was demonstrated during the anovulatory wave as well as during the ovulatory waves, and the diameter of the future dominant follicle at the beginning of deviation was s...
Higgins AJ, Lees P, Taylor JB.In a two part cross-over experiment, acute inflammatory exudates were induced in 7 ponies by subcutaneous implantation of 3 sterile carrageenin-soaked polyester sponge strips. Treatment comprised a single therapeutic geenin-soaked polyester sponge strips. Treatment comprised a single therapeutic dose of 4.4 mg/kg phenylbutazone (PBZ) administered intravenously at the time of sponge implantation. Exudates were harvested at 6, 12 and 24 hours and examined for leukocyte and erythrocyte numbers using the improved Neubauer technique; for eicosanoids by radioimmunoassay and by high performance liqui...
Gibson KT, Trotter GW, Gustafson SB.Uroperitoneum as a sequela to urethral calculus in an adult gelding was successfully managed by use of subischial urethrotomy and abdominal drainage. Necrosis of bladder mucosa was seen endoscopically, but a tear or rupture was never identified. Peritonitis developed but was controlled with antibacterial treatment. Although uroperitoneum is usually a sequela to bladder rupture and the ideal treatment is surgical repair, conservative management may be warranted in selected cases.
Houghton E, Dumasia MC.1. After intramuscular administration of [4-14C]testosterone to two cross-bred gelded horses, 45% of the radioactivity was excreted in urine in 96 h. Small amounts of urinary activity could still be detected at 200 h. 2. Neutral metabolites obtained after both enzyme and acid hydrolysis of urine samples have been investigated by g.l.c.-mass spectrometry. 3. 5 alpha-Androstane-3 beta, 17 alpha-diol was found only in the enzyme-hydrolysable extract and testosterone only in the acid-hydrolysable extract. 5 alpha-Androstane-3 beta, 17 beta-diol and 3 beta-hydroxy-5 alpha-androstan-17-one were foun...
Scherzer J.Reproductive performance in mares can be enhanced by various techniques. Protocols hastening the onset of follicular development help establish pregnancy in mares and ensure that foals are born early in the year. The time spent breeding mares can be reduced by synchronizing estrus and inducing ovulation. After successful fertilization of the oocyte, the developing embryo can survive in the uterus only if postbreeding endometritis, if present, is treated.
Löfqvist L, Pinzke S.The horse industry in Sweden has rapidly expanded in recent years. This increasing number of horses implies a greater need for more farriers. Shoeing a horse is hard physical work, and includes awkward work postures and repetitive movements. It is well known that hard physical work increases the risk of injuries and musculoskeletal problems. The risk is especially high for musculoskeletal disorders when certain movements are constantly repeated. Heavy or repeated unilateral loads lead to considerable stress on the muscles, which can lead to rupture and fatigue that can cause long term problems...
Reiwald D, Riond JL.The copper and zinc contents of 25 rations for adult horses were evaluated. The total amount of copper and zinc daily ingested was obtained by adding the amount of each element contained and added of the commercial feed to the amount contained in ingested hay and oats. The total amount of copper and zinc ingested daily was compared with the official recommendations for the maintenance of an adult horse of 550 kg. The results show that a traditional ration oats/hay does not contain a sufficient amount of copper and zinc in order to cover their respective requirements. Furthermore, many rations ...