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.
Tulleners EP, Richardson DW, Reid BV.Three mares were treated for vaginal evisceration of a portion of the small intestine. Evisceration occurred in 2 mares shortly after breeding accidents in which the stallion's penis penetrated the vaginal fornix dorsal to the cervix. The affected bowel was replaced through the laceration, and the vaginal defects were sutured with the mares standing, utilizing epidural anesthesia. One mare recovered without complications, was subsequently bred, and delivered a foal with no difficulty. The other mare developed signs of a strangulating small intestinal obstruction 24 hours after the injury, nece...
Hinrichs K, Gentile DG, Hurtgen JP, Richardson DW.A testicular prosthesis was removed from the scrotum of a 3-year-old Quarter Horse stallion. The prosthesis had been placed in the left side of the scrotum 10 months earlier, after an unsuccessful attempt to reposition the retained left testis. Because of a persistent draining fistula on the scrotum, first noted 5 months after placement of the prosthesis, surgery was performed to remove the prosthesis. At surgery, the left testis was found in a fibrous mass surrounding the prosthesis. The left testis had descended after placement of the prosthesis, and its involvement in the fibrous tissue sur...
Chiapetta JR, Baker JC, Feeney DA.An Arabian foal, which was recumbent for 4 days, had signs of extensor rigidity of the thoracic limbs and hypotonic paralysis of the pelvic limbs. Survey radiography revealed a lesion at T15, with radiographic impression of a compression fracture or a hemivertebra. Postmortem examination revealed a fracture at T15. Clinical and pathologic findings in this case were compatible with the Schiff-Sherrington syndrome, which is characterized by thoracic limb extensor hypertonia associated with paraplegia from acute thoracolumbar trauma.
Scott EA, Todhunter R.In 2 cases of chronic intestinal intussusception in horses, one involved jejunum and the other, ileum. The only clinical signs observed were intermittent colic. Surgery was performed on both horses, with successful outcomes.
Hubbell JA, Muir WW.The rate of rise of arterial partial pressure of carbon dioxide (PaCO2) was determined in 49 apneic halothane-anesthetized horses following controlled ventilation. Drugs given for induction of anesthesia did not affect the rapid rate of rise of PaCO2 during the first minute after controlled ventilation, the PaCO2 at 1 minute after controlled ventilation, or the PaCO2 at which spontaneous ventilation began. Horses given xylazine-ketamine for induction of anesthesia had a significantly (P less than 0.05) faster rate of rise of PaCO2 after 1 minute following controlled ventilation than did horses...
Freeman KP, Roszel JF, Slusher SH.Inclusions and cellular changes were seen in cytologic specimens from 1 healthy horse, 6 horses hospitalized because of respiratory problems, and 1 horse hospitalized because of colic and hepatitis. Two bronchial aspirates contained detached ciliated cytoplasmic tufts and cytoplasmic inclusions characteristic of the specific degenerative process called ciliocytophthoria. These changes and inclusions resembled those seen in bronchial aspirates from human beings with parainfluenza virus infection. Four bronchial aspirates and 2 serous fluid specimens had nuclear inclusions resembling those seen ...
Murray MJ, Crowell-Davis SL.A 4-year-old mixed-breed gelding was presented with colic-type behavior of 5 days' duration that included pawing, looking at the flank area, and kicking and biting at the abdomen and flank when it was eating hay or grain. Medical evaluation did not reveal the cause of the "colic." During its stay in the hospital, the horse improved as regarded the colic-type behavior while eating, but resumed this behavior when it was able to see hay that it was not allowed to eat. It was determined that the persistent colic-type behavior developed as a result of the horse having been repeatedly displaced from...
Lynch JA, Binnington BD, Artsob H.A 4-fold or greater seroconversion to the snowshoe hare serotype of the California serogroup of viruses in a horse with acute encephalitis was demonstrated by hemagglutination-inhibition, complement-fixation, and neutralization tests. The horse had a mild fever, was ataxic, had a head tilt, and was observed to circle. Chloramphenicol, dexamethasone, and B complex vitamins were administered and the horse recovered. The snowshoe hare virus is a recognized human pathogen, but it has not been associated with disease in horses. It is unknown whether horses play a role as amplification hosts for the...
Simmons HA, Cox JE, Edwards GB, Neal PA, Urquhart KA.This paper reports seven cases of penile paraphimosis which occurred in both entire and castrated horses in association with general debility. Two cases were discharged after treatment while still suffering from partial paralysis; one was discharged at the owner's request with complete paralysis; three were destroyed and one died during treatment. Identified causes of debility were malnutrition, severe parasitism, glucose malabsorption and salmonellosis.
DiPietro JA, Todd KS, Lock TF, Reuter-Dallman V.Fifty horses from a herd known to have benzimidazole-resistant small strongyles were treated with febantel (6 mg/kg), combinations of febantel (6 mg/kg) and piperazine citrate (25 or 55 mg base/kg), thiabendazole (44 mg/kg), or placebo (0.6 ml of water/kg). Pretreatment and 7-day posttreatment fecal examinations were done. Fecal cultures, strongyle egg per gram (epg) counts, sugar flotation fecal examinations, and in vitro testing for benzimidazole resistance were performed. Results of fecal examinations before treatment were similar in all horses, and results of testing were positive for benz...
Biberstein EL, Jang SS, Hirsh DC.From 1965 to 1983, Nocardia asteroides infection was diagnosed in 16 horses at the Veterinary Medical Teaching Hospital, University of California, Davis. In 2 of the cases, the infection was traumatic in origin and local in extent; the horses recovered without relevant antimicrobial therapy. Fourteen horses had pulmonary or disseminated infections that ended fatally. All 14 had various degrees of immunosuppression. Of these, 8 were Arabian foals with combined immunodeficiency disease and 3 were aged horses with hyperadrenocorticism secondary to ACTH-secreting pituitary tumors. Of the other 3, ...
Swanson CR, Muir WW, Bednarski RM, Skarda RT, Hubbell JA.The hemodynamic changes induced by constant infusions of dopamine or dobutamine (each 3, 5, and 10 micrograms/kg/min) were observed in halothane-anesthetized horses. Left ventricular dp/dt and cardiac output were increased in horses given dobutamine at dosage of 3 micrograms/kg/min and in those given either of the drugs at dosages of 5 and 10 micrograms/kg/min. Concomitant increases in systemic arterial blood pressure occurred at lower infusion dosage rates of dobutamine than those of dopamine and were modulated by dosage-related changes in peripheral vascular resistance that were different be...
Matsui K, Amada A, Sawazaki H.Electrocardiographic observation in 10 Thoroughbred horses has been carried out from fetal stages to 12 months after birth. In this observation a filly out of 10 foals at a resting state showed second-degree atrioventricular {A-V) block with sinus arrhythmia after 2.5 months of age. The number of dropped beats and the irregularity of sinus arrhythmia in these blocks were affected by the atrial rate, and several variations of Wenckebach phenomenon were shown under the influence of the artial rate. Electrocardiographic characteristics of second-degree A-V block in the present filly might be simi...
Crowe MW, Swerczek TW.In a 13-year survey of equine congenital defects that resulted in death or required euthanasia in central Kentucky, necropsies were performed on 608 deformed fetuses or newborn foals. The following congenital anomalies were observed: contracted foal syndrome (33.2%), miscellaneous limb contraction (20%), multiple defects (5.3%), microphthalmia (4.6%), craniofacial malformations (4.3%), cleft palate (4.0%), heart defects (3.5%), umbilical defects (3.5%), and hydrocephalus (3.0%). Eleven less frequently occurring anomalies constituted the balance of the congenital defects in fetuses and newborn ...
Morris DD, Garcia MC.Adrenal and/or thyroid gland function tests were evaluated in horses at various times during short-term therapy with phenylbutazone, stanozolol, and boldenone undecylenate. There were no significant treatment or time effects on mean basal plasma cortisol concentrations in horses during treatment with the following: phenylbutazone, given twice daily (4 to 5 mg/kg, IV) for 5 days; stanozolol, given twice weekly (0.55 mg/kg, IM) for 12 days; boldenone undecylenate, given twice weekly (1.1 mg/kg, IM) for 12 days; or nothing. There was no significant effect of phenylbutazone treatment on the change...
Adamson PJ, Wilson WD, Hirsh DC, Baggot JD, Martin LD.In vitro antimicrobic susceptibility patterns of commonly isolated aerobic gram-positive and gram-negative bacterial pathogens of equine origin were determined, using the agar-plate dilution method. All organisms were recent clinical isolates and included Corynebacterium (Rhodococcus) equi, Corynebacterium pseudotuberculosis, (coagulase positive) Staphylococcus sp, Streptococcus equi, Streptococcus zooepidemicus, Actinobacillus sp, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella. In vitro susceptibility levels were outlined for 14 antimicro...
Traub-Dagartz J, Bayly W, Riggs M, Thomas N, Pankowski R.An Arabian foal with a congenital heart disease died due to hemorrhage secondary to a large gastric ulcer. Previously, death of foals with gastric ulcers has been due to diffuse peritonitis resulting from gastric ulcer perforation. The foal in this case report died due to hemorrhage secondary to a large gastric ulcer.
Barclay WP, Foerner JJ, Phillips TN.Axial sesamoid injuries were found in 4 of 18 horses with lateral condylar fractures of the metacarpus or metatarsus. The injuries appeared as axial sesamoid fractures or progressive demineralization of the axial border of one of the sesamoids. None of the horses with axial sesamoid injuries returned to performance soundness. Axial sesamoid injury appeared to be an indication of severe fetlock trauma due to condylar fracture. Such injuries appeared to indicate a poor prognosis for return to performance soundness.
Rigg DL, Ramey DW, Reinertson EL.Respiratory distress and laryngeal paralysis were found to be caused by a Streptococcus equi abscess of cranial mediastinal lymph nodes, putting pressure on the trachea at the thoracic inlet. Surgical drainage was required to relieve the compression, and long-term antibiotic therapy was used to treat the bacterial infection. The trachea returned to normal diameter but left laryngeal hemiplegia persisted. Peritracheal abscesses should be considered in the differential diagnosis of inspiratory dyspnea of the horse.
Chvala S, Nowotny N, Kotzab E, Cain M, van den Hoven R.To evaluate use of the acupuncture meridian test for detection of recent or recently reactivated equine herpesvirus type 1 (EHV-1) infection in horses with decreased performance. Methods: Case-control study. Methods: 40 horses. Methods: Physical and neurologic examinations were performed, and acupuncture points on the bladder meridian were tested for sensitivity reactions in case and control horses. Polymerase chain reaction assays were performed to determine whether EHV-1 or equine herpesvirus type 4 (EHV-4) DNA could be detected in peripheral blood mononuclear cells. Complement fixation (CF)...
Bryant B, Meehan LJ, Roberts V.Standing computed tomographic (CT) examination of the equine guttural pouch frequently reveals deviation of the midline septum. The significance of deviation is currently unknown. The aims of this retrospective, single-centre study were to determine the prevalence of deviation of the midline septum of the guttural pouch and determine whether there was an association between the presence and degree of deviation of the septum, and guttural pouch disease. Case records were reviewed, identifying 95 horses that had undergone a standing, sedated, head CT and guttural pouch endoscopy. The presence, l...
Zierz J, Wintzer HJ.To judge acute processes of pain objectively the results are told of a determination of adrenaline and noradrenaline in the plasma of 30 horses suffering from pain. Besides a scheme basing on an awarding of points is developed to ascertain changes of physiological and ethological parameters caused by pain. These results in changes of behaviour are compared to results determined by laboratory experiments. Concerning pain of medium and high level a relation to the concentration of catecholamines is noticed. Therefore the total of certain clinical observations is suitable for graduating acute pai...
Huber MJ, Grisel GR.An 18-month-old 450-kg [990-lb] sexually intact male Holsteiner was evaluated for lameness of the left forelimb of 3-months' duration. We were unable to localize the site of lameness, using intra-articular and perineural anesthesia, and radiography of the shoulder and cubital joint (elbow) did not reveal radiographic abnormalities. Nuclear scintigraphy was performed. An increase in radio-isotope uptake was evident at the lateral epicondyle of the left humerus. Radiographs of the region 3 weeks later revealed a 1.5-cm focal lucency surrounded by a 1.0-cm rim of necrotic bone. The lesion was con...
Abuja GA, Bubeck KA, Quinteros DD, García-López JM.The clinical signs, radiographic findings, surgical treatment, and outcome of three horses with luxation of the distal tarsal joints are reported. Two patients showed luxations of the tarsometatarsal joint whereas luxation of the proximal intertarsal joint was found in one case. Open reduction, followed by internal fixation was performed in two horses and closed reduction with a transfixation pin cast was performed in the third. The treatment in all three cases resulted in a satisfactory clinical outcome.
Yovich JV, Hilbert BJ, McGill CA.Nineteen cases of fracture of the distal phalanx in horses are reviewed. This represented 1.1% of the total number of horses seen at Murdoch University Veterinary Hospital (MUVH) over a 32-month period. All horses were managed conservatively. Eight horses made a complete recovery. Three are being trained again and are not lame. Four horses made a limited recovery. Two horses are still resting and one horse was killed humanely when it still showed lameness after 2 years. One horse was killed humanely after the fracture was first diagnosed.
Pusterla N, Mapes S, Leutenegger CM.A questionnaire was developed to document the knowledge base of large-animal diplomates of the American College of Veterinary Internal Medicine (ACVIM) regarding polymerase chain reaction (PCR) technology and to identify the common use of this technology in equine practice. Ninety-three of the 278 mailed questionnaires were returned, for an overall response rate of 33.4%. Ninety respondents (99%) reported being familiar with the general principles of nucleic acid probe technology; however, only 52 (57%) knew the difference between conventional (traditional) and real-time (second-generation) PC...
Kritchevsky J, Olave C, Tinkler S, Tropf M, Ivester K, Forsythe L, Couetil L.The use of thyroid supplement is pervasive in athletic horses although its effects on measures of performance are not known. Objective: One purpose of this study was to determine whether supra-physiologic doses of levothyroxine affect the velocities at which blood lactate was greater than 4 mmol/L (VLa4 ) and heart rate was over 150 (V150 ) and 200 (V200 ) beats per minute respectively. Additionally, a survey of post-race blood samples was also conducted to determine whether high thyroxine concentrations were common in racehorses. Methods: A randomised, crossover, trial was performed in six h...
Hammock PD, Freeman DE, Magid JH, Foreman JH.A 12-year old 573-kg (1,261-lb) Quarter Horse gelding was referred with colic of 12 hours' duration and with poor response to medical treatment. On the basis of physical and laboratory findings, a pelvic flexure impaction was suspected. The horse was treated medically. Because signs of mild abdominal pain persisted and the heart rate had increased, an exploratory celiotomy was performed 30 hours after signs of colic were first noticed. At surgery, the ileum was found partially entrapped within the epiploic foramen, in a left-to-right direction, to form a parietal hernia. The entrapped intestin...
Carlson KL, Chaffin MK, Corapi WV, Snowden KF, Schmitz DG.The starry sky hepatic pattern is an unusual ultrasonographic appearance of equine liver characterized by numerous small, hyperechoic foci, some of which cast an acoustic shadow, distributed randomly throughout the hepatic parenchyma. Our objectives were to describe the signalment, clinical signs, clinicopathological findings, primary disease process, and ultrasonographic findings of horses with this ultrasonographic pattern, as well as determine the associated gross and histologic changes. The starry sky pattern was identified in 18 adult horses of mixed gender and breed. The horses had vario...
Bridges CG, Edington N.Equine sera were used to immunoprecipitate radiolabelled virus-infected cell proteins; subsequent resolution with polyacrylamide gel electrophoresis identified the EHV-1 polypeptides VP 2, 10a, 11, 13, 14, 15, 16, 20, 21 and 23a. The humoral support of ADCC by these sera was examined in vitro. Cytotoxicity could be demonstrated against both subtypes irrespective of the immunising isolate. The implications of these results are discussed.
Pinaffi FL, Khan FA, Silva LA, Beg MA, Ginther OJ.The effects of a PRL-stimulating substance (sulpiride) on PRL and PGF2α secretion and on luteal and ovarian follicular dynamics were studied during the estrous cycle in mares. A control group (n = 9) and a sulpiride group (Sp; n = 10) were used. Sulpiride (25 mg) was given every 8 h from Day 13 postovulation to the next ovulation. Repeated sulpiride treatment did not appear to maintain PRL concentrations at 12-h intervals beyond Day 14. Therefore, the hypothesis that a long-term increase in PRL altered luteal and follicular end points was not testable. Hourly samples were collected from the h...
Gauvreau GM, Wilson BA, Schnurr DL, Young SS, McDonell WN.The purpose of this study was to develop a technique to measure the oxygen cost of ventilation and the values of ventilatory parameters in seven normal horses rebreathing carbon dioxide (CO2). All the horses responded to increased inspiratory levels of CO2 by increasing their tidal volume (VT) and frequency of breathing (Vf). The mean (SE) oxygen cost litre-1 of ventilation, measured at rates of ventilation greater than 200 litres min-1 was 1.7 (0.04) ml litre-1, similar to that of normal human subjects ventilating submaximally. It was concluded that the CO2 rebreathing test is a practical, no...
Gleed RD, Dobson A, Hackett RP.In the quietly standing horse the bronchial arterial blood flow is low, 0.1-0.2% of the pulmonary arterial flow. In horses anaesthetized with halothane, the bronchial arterial flow is reduced by a greater fraction than that in the pulmonary artery. Thus the shunting through the bronchial circulation is decreased about 3-fold by anaesthesia, and cannot, therefore, contribute significantly to the increased alveolar-arterial gradient seen in dorsal recumbency. The results indicate bronchial vasoconstriction under anaesthesia.
Raidal SL, Wright JD.Records of 220 thoroughbred horses presented to the Randwick Equine Centre or the University of Queensland Veterinary Teaching Hospital for surgical management of carpal injury were reviewed. Details of racing performance were obtained, enabling evaluation of racing success following surgery. Age and sex matched control horses not known to have suffered carpal injury were selected from the Australian Stud Book and the Australian Racehorse Register. Control and treated populations were compared in terms of overall career racing success. Radiographs or xeroradiographs from 198 horses were availa...
Al-Bagdadi FK, Eilts BE, Richardson GF.Scanning electron microscopy (SEM) was used to study the endometrium of nine 1-year-old thoroughbred mares after twice intrauterine infusions of gentamicin, on 2 consecutive days. Five mares were infused on 2 consecutive days with 40 ml gentamicin (50 mg/ml) mixed with 80 ml of normal saline. Four mares served as controls and were infused with 120 ml of saline on 2 consecutive days. Endometrial biopsies were obtained from all mares 3 days after the second intrauterine infusion. Each biopsy was processed for SEM by standard methods. The endometrial epithelium of the gentamicin-infused mares had...
Sinn D, Wintzer HJ.The pharmacokinetics of racemic phenprocoumon were studied in 8 adult horses after the single intravenous and oral administration of 0.75 mg/kg. After i.v. administration the plasma concentration of phenprocoumon showed a biphasic decline in time. The pharmacokinetics were calculated on the two-compartment open model. The average plasma half-life (beta-phase) was 22 hours, the apparent volume of distribution was 0.61 l/kg, Cltot was 25.2 ml/kg/h (13.9-40.9 ml/kg/h). The systemic bioavailability of oral phenprocoumon was 97.6%, Tmax was found to be 4-12 hours. The effect of phenprocoumon on the...
