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.
Rawlinson RJ, Jones RT.The history and clinical findings of 1 horses with guttural pouch mycosis referred to us are described. The salient features of the history and clinical signs common to both cases were profuse spontaneous nasal haemorrhage, partial pharyngeal paralysis; subsequently bilateral nasal discharge containing food material, inability to drink and parotid pain became evident. One case made a gradual recovery with conservative medical treatment while the second case was destroyed and submitted for post-mortem, histopathological and microbiological examination. This examination failed to establish the i...
Dietz WH, Alvarez O, Martin DH, Walton TE, Ackerman LJ, Johnson KM.Forty-five horses were infected peripherally or intrathecally with enzootic or epizootic strains of Venezuelan equine encephalomyelitis (VEE) virus. Low titers of virus appeared in cerebrospinal fluid (CSF) after peripheral inoculation of enzootic or epizootic VEE virus strains. Intrathecal infection with either epizootic or enzootic VEE virus produced higher titers of virus in CSF than did peripheral infection. In contrast to peripheral infections with enzootic strains, intrathecal infections with these strains caused death. The animals that died had widespread histopathologic changes and lar...
Kingsbury HB, Quddus MA, Rooney JR, Geary JE.The distal portion of the forelimb of the horse is provided with a stay apparatus composed of tendons, ligaments, and fascia. This stay apparatus provides the major resistance to joint flexion during the support phase of the stride. The laboratory test system described was shown to be able to reproduce in vitro limb motions and hoof forces measured with a running horse. These results indicated the stay apparatus operates in a largely passive mode, active muscle contraction apparently serving to provide rigidity only early in the support phase of the stride. The testing system described was des...
Wentink GH.The movements of the right hind limb of horses with normal locomotion were studied using cinephotography and electromyography. A model of the cycle of a stride in the walk and the trot was constructed and the kinetic parameters of the segments of the limb were calculated. A good correlation was obtained between the kinetics and the periods of the cycle of a stride during which individual muscles display activity. The results of this study demonstrate that: at placing and lifting, i.e., when a change occurs in the direction of the movement of the limb; b) At the walk, the greatest forces operan...
Perryman LE, McGuire TC.Combined immunodeficiency in horses is a genetic disorder in which there is a defect in the production of committed B and T lymphocytes. In this study, peripheral blood mononuclear leukocytes from foals with combined immunodeficiency were examined for their capacity to stimulate and respond in one-way mixed lymphocyte cultures. Irradiated cells from combined immunodeficient foals were uniformly capable of stimulating cells from unrelated horses. However, none were able to respond to allogeneic stimulation. Examination of cells from known carrier horses revealed no difference in capacity to sti...
McIlwraith CW, Fessler JF.The usefulness of inferior check ligament desmotomy as a treatment for acquired tendon contracture in horses was evaluated in 13 cases of deep digital flexor (DDF) contracture and in 3 cases of combined superficial digital flexor (SDF) and DDF contracture. In 8 of 9 cases of DDF contracture in which the dorsal surface of the hoof had not passed beyond being vertical to the ground, the surgical procedure was successful in returning the limb to a normal position and function. Compared with DDF tenotomy, inferior check ligament desmotomy was a superior treatment technique because of decreased pos...
Johnson L, Amann RP, Pickett BW.Changes within the equine seminiferous tubules during the cycle of the seminiferous epithelium were studied light and scanning electron microscopy (SEM). Once observed with SEM, tubules were sectioned and staged using light microscopy. As viewed by SEM, the weblike, spongy cytoplasm of germ cells or Sertoli cells in stages I and II extended over the entire height of the germinal epithelium. The cytoplasm of the basal portion of the germinal epithelium in stages III to VIII was similar to that in stages I and II. However, the cytoplasm which occupied the luminal third of the epithelium in stage...
Gentry PA, Woodbury FR, Black WD.The clotting times obtained with different assay procedures for routine coagulation tests were examined for horse and pony samples. The whole blood clotting time test and the activated coagulation test seemed to give similar results when both tests were done at 22 C. The results obtained for the activated partial thromboplastin time assay varied, depending on the commercial reagent used for the test. Consistent results were obtained for the one-stage prothrombin time assay with each reagent used.
Meuten DJ, Butler DG, Thomson GW, Lumsden JH.Chronic granulomatous enteritis associated with weight loss and hypoproteinemia was identified in 2 horses. Both horses continued to have normally formed feces. Malabsorption of carbohydrate and lipid, with concomitant gastrointestinal protein loss was demonstrated in 1 case. One horse was treated symptomatically and gained 108 kg. In both cases, principal gastrointestinal lesions were partial to total villus atrophy and transmural mononuclear leukocytosis, with lymphocytes and histiocytes predominating. The cause of the condition was not identified in either case.
Rumbaugh GE, Smith BP, Carlson GP.internal abdominal abscesses in 25 horses, including 8 horses that died or were euthanatized, were found to be caused by Streptococcus equi, Streptococcus zooepidemicus, or Corynebacterium pseudotuberculosis. Breed or sex predilection was not found. Although horses of all ages were affected, those under 5 years of age were more commonly affected. Nearly all of the horses had a history of respiratory catarrh or lymphadenitis. Horses with internal abdominal abscesses also had intermittent, prolonged colic or chronic weight loss. Most horses had increased rectal temperature, increased heart and r...
Robinson NE, Sorenson PR.Obstruction of the upper and lower airways is common in horses. In the upper airway, paresis of abductor muscles of the nares and larynx allows inspiratory collapse of soft tissues, which is accentuated by factors increasing upper airway resistance and by high inspiratory flow rates. Intrapulmonary airway obstruction occurs due to accumulation of secretions, release of chemical mediators in response to a variety of stimuli, and parasympathetic stimulation of airways. Obstruction of large airways increases the work of breathing, whereas obstruction of small airways may cause no measurable incre...
Hoff GL, Bigler WJ, Buff EE, Beck E.Research and surveillance programs relating to the occurrence and distribution of western equine encephalomyelitis virus in Florida, conducted between 1955 and 1976, suggest that the virus is (1) an endemic arbordae, (2) transmitted in a continuous cycle throughout the year by Culiseta melanura mosquitoes, and (3) restricted to fresh water swamps and waterways in central, north, and northwest Florida.
Kemen MJ, McClain DS, Matthysse JG.Equine infectious anemia virus was transmitted from an acutely ill and an inapparently infected pony to uninfected ponies by the interrupted feeding of horse flies (tabanids). Transmission from acutely ill ponies was not accomplished following: (1) the interrupted feeding of a single horse fly, (2) bites of horse flies that had fed on an acutely affected pony 24 hours earlier, (3) bites of horse flies that had oviposited after feeding on an acutely affected pony, or (4) the inoculation of larval material derived from horse flies that had fed to repletion. It was concluded that horse fly transm...
Forster HV, Bisgard GE, Dempsey JA, Orr JA.Numerous studies have demonstrated the existence of an intracranial [H+] chemoreceptor mechanism capable of stimulating ventilation. 1 Supposedly, this chemoreceptor is located 0.2 mm below the surface of the ventrolateral side of the medulla and is responsive to [H+] in the surrounding cerebral extracellular fluid (ECF). During chronic conditions, ECF [H+] is supposedly in equilibrium with CSF [H+]; hence, stimulus level can be established through sampling and analysis of CSF. In this presentation, we summarize data from studies on spontaneously breathing, unanesthetized ponies which suggests...
Kelly DF, Pinsent PJ.A 10-month-old thoroughbred colt developed sudden complete blindness; no other neurological abnormality was detected. At necropsy 3.5 months later lesions were confined to both optic pathways in which there was extensive degeneration of axons and myelin and gliosis. The cause of the optic lesion was not determined but the lesion may be a toxic neuropathy.
Newton SA, Knottenbelt DC, Daniel EA.The surgical repair of a traumatic injury to the parotid (Stenson's) duct of an adult horse is described and compared with previous reports. The diagnosis was confirmed by the analysis of a flow of saliva-like fluid observed while the horse was eating. The repair was attempted under general anaesthesia three days after the injury. Surgical anastomosis was considered to have improved the rate of healing. However, there was some evidence of leakage of saliva from the site for three days after the removal of the in-dwelling catheter, seven days postoperatively. A full recovery followed.
Dupont J, Gougnard A, Salciccia A, Detilleux J, Serteyn D, Sandersen C.To compare the efficacy of single-breath continuous positive airway pressure manoeuvre (CPAP-M) with inhaled salbutamol, and a combination of both. Methods: Randomized, clinical study. Methods: A total of 62 client-owned horses (American Society of Anesthesiologists status III-V) anaesthetized for laparotomy. Methods: Horses were premedicated with intravenous (IV) xylazine (0.4-0.6 mg kg), anaesthesia was induced with midazolam (0.06 mg kg IV) and ketamine (2.2 mg kg IV) and maintained with isoflurane in oxygen using volume-controlled ventilation without positive end-expiratory pressure. If Pa...
Herb VM, Url A, Tichy A, Nell B.Establishing an immunohistochemical approach for semi-quantitative assessment of the presence of immunoglobulin G (IgG) in equine, canine, and feline corneas. Methods: Healthy corneas of horses, dogs, and cats, euthanized because of a fatal disease or an unrecoverable trauma unrelated to and without a history of ophthalmic disease were formalin-fixed, paraffin-embedded, and determined to be pathomorphologically healthy by light microscopy. Automated immunohistochemistry was performed using primary antibodies against IgG, biotin-conjugated secondary antibodies, and streptavidin-peroxidase, as w...
Hawkins A, Chapman L, Meter M, Smith RK.To report the diagnostic features and clinical outcome of horses with digital flexor tendon sheath (DFTS) synoviocoeles treated tenoscopically under ultrasonographic guidance. Methods: Retrospective case series. Methods: Client-owned horses (n = 10). Methods: Medical records were searched for horses with lameness localized to the region of the DFTS and clinical evidence of a fluid-filled mass (synoviocoele) associated with the DFTS. Diagnostic imaging and surgical findings, together with long-term outcome, were reported. Results: Lameness and synoviocoeles were unilateral (5 forelimbs, 5 hin...
Barton CK, Sandow CB, Rodgerson DH.To describe an arthroscopic technique for the removal of osteochondral fragments located within the condylar fossa of the third metacarpal/tarsal bone. Methods: Retrospective study. Methods: Thoroughbred yearlings (n = 11). Methods: Osteochondral fragments located within the condylar fossa of the third metacarpal/tarsal bone identified during presale radiographic examination were removed via arthroscopy, assisted with ultrasonography in select cases. Complete fragment removal was confirmed by intraoperative radiography. Results: Fragments were successfully removed using rongeurs following di...
Ensink JM, Klein WR, Barneveld A, van Miert AS, Vulto AG.To evaluate the side effects of oral pivampicillin and trimethoprim/ sulphadiazine, 200 horses receiving these antimicrobial agents were studied. The horses received either trimethoprim/ sulphadiazine (30 mg/kg twice daily) or pivampicillin (25 mg/kg twice daily) for three or more days. No adverse effects other than loose faeces and diarrhoea were detected. The risk of diarrhoea was significantly less after the oral administration of pivampicillin (3 per cent) than after trimethoprim/ sulphadiazine (7 per cent). Horses whose appetite was reduced appeared to be predisposed to develop diarrhoea ...
Rath D, Leiding C, Klug E, Krebs HC.Ejaculates were collected at 3-day intervals before, during and after a washing procedure with chlorhexidine (2%). Semen motility and pathology were determined before and after deep-freezing. Blood samples were taken before and within 1 h after washing procedures and then extracted in ether. This was followed by HPL chromatography. Chlorhexidine concentrations in blood and seminal plasma were distinctly higher in the treated stallions than in control groups. Concentrations in the control groups were below the detection limit of the column. Significant correlations between decreasing semen qual...
Henderson K, Stevens S, Bailey C, Hall G, Stewart J, Wards R.The relative merits of measuring blood concentrations of equine chorionic gonadotrophin (eCG, previously known as pregnant mare serum gonadotrophin (PMSG)), or oestrone sulphate (OS), or faecal OS concentrations for determining pregnancy status in miniature horses were investigated. Pregnant mares between 40 and 140 days after mating had serum eCG concentrations > 1 I.U. mL-1, with the highest concentrations occurring between days 50 and 120. However, eCG measurements were susceptible to returning a 'false positive' diagnosis of pregnancy. Plasma OS concentrations ranged from 0.1 to 3.6 ng ...
Whitehair KJ, Parker JE, Smith GN, Adams SB, Bottoms GB.Serum levels of type III procollagen peptide (P-III-P) were measured by radioimmunoassay in clinically normal adult ponies (n = 15) and horses (n = 10). The mean serum levels of P-III-P from the ponies, 10.4 +/- 2.9 (SD) ng/mL, and the horses, 12.2 +/- 2.6 (SD) ng/mL, were not significantly different. Segments of jejunum were made ischemic to induce fibrous peritoneal adhesions in two ponies, and serum P-III-P levels were measured on days 4, 5, 7, 14, and 21. An exploratory celiotomy on day 21 revealed that the ischemic injury had induced fibrosis of the mesentery and bowel, but no adhesions h...
Delvescovo B, Mullen KR, Eicker SW, Ivanek R, Ainsworth DM.Previously we described a clustering of dysphagic foal cases on a Pennsylvania (PA) Standardbred farm which was associated with exposure of pregnant mares to high concentrations of polycyclic aromatic hydrocarbons (PAHs) in the well water. The effect of dysphagia on future athleticism was uncertain. Objective: To determine if, as adults, dysphagic foals were less likely to race and if athleticism (age of first race, Speed Index and Earnings Per Start Index) differed from that of healthy foals that raced as adults. Methods: Prospective cohort study. Methods: All foals born during the study peri...
Wilson RB, Haffner JC.Right atrioventricular atresia with a ventricular septal defect, a rare congenital cardiac anomaly of either animals or man, was diagnosed in a one week old Arabian foal. The foal had been weak and cyanotic since birth, sometimes becoming dyspneic when stressed. Necropsy revealed a dilated and hypertrophied left ventricle with the right ventricle being small. The right atrioventricular valve was absent. The right and left ventricles communicated via a septal defect which was located immediately adjacent to the aortic valve.
Bader H, Röhrsheim C, Koene M, Meinecke B.Investigations in different species including the horse have demonstrated that prostaglandin F2 alpha (PGF2 alpha) is involved in initiating uterine contractions occurring during mating and artificial insemination (A.I.). Uterine contractions play an important role with respect to the sperm transport within the female genital tract. The objective of the present investigation was to evaluate whether the administration of PGF2 alpha (Dinoprost) synchronously to A.I. could have a positive effect on the pregnancy rate in mares. A field study including 346 warmblood-mares (age two to 20 years) belo...
Robinson JA, Allen GK, Green EM, Garner HE, Loch WE, Walsh DM.Serum interleukin-6 (IL-6) concentration was measured in 11 colostrum-fed (CF) and 8 colostrum-deprived (CD) 2- to 3-day-old foals after foals were infused with lipopolysaccharide (LPS; Escherichia coli O55:B5 endotoxin, 0.5 microgram/kg of body weight in sterile saline [0.9% NaCl] solution). Four CF and 2 CD foals were given saline solution alone. Serum IL-6 concentration was estimated by use of an in vitro proliferative bioassay, using the IL-6 dependent B.13.29 clone 9 cells. Interleukin-6 concentration increased in all LPS-infused foals, and geometric mean serum IL-6 concentration was sign...
Belknap JK, Moore JN.The records of 71 horses with small intestinal disorders requiring surgical correction were disorders requiring surgical correction were reviewed to compare the prevalence of laminitis in those horses treated prophylactically with heparin and the prevalence of horses not treated with heparin. The prevalence of laminitis was 13% (9/71), and there was no significant difference (P less than 0.05) in the prevalence of laminitis between the 2 groups. The lack of significant benefit after treatment with heparin indicates that further work needs to be done on the equine coagulation system before hepa...
Gilroy BJ, Bellamy J.An unusual case of impaction colic caused by the ingestion of large quantities of gravel. The clinical presentation, surgical findings, and outcome are described.
