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.
Roberts MM, Oroszlan S.Capsids of equine infectious anemia virus have been isolated as cone-shaped particles 60 x 120 nm in size. Detergent treatment of whole virus followed by two cycles of rate-zonal centrifugation in Ficoll produces these capsids in a yield of approximately 10%. The major protein components are the gag-encoded p11 nucleocapsid protein and p26 capsid protein, which are present in equimolar amounts. Substantial cleavage of p11 to p6 and p4 can be observed under conditions where the viral protease packaged in the capsid is enzymatically active.
Baird AN, True CK.Two horses were referred with fragments of nasogastric tubes as esophageal foreign bodies. Radiography and endoscopy were used to identify the location of the fragments. Portions of the tubes were retrieved by esophagotomy in 1 horse and by manual examination of the oral cavity in the other. Both tubes were friable in focal areas, but were quite pliable over most of the length of the tube.
Wilson DG.A 3-year-old Standardbred gelding was referred for evaluation of a fluctuant swelling that developed over the dorsum of the carpus subsequent to arthroscopic surgery on that carpus. A synovial hernia was diagnosed and surgically repaired. Although complications secondary to arthroscopy are rare, synovial herniation can develop after arthroscopic surgery. The condition must be differentiated from the more common true bursitis or false bursitis that is commonly referred to as a hygroma.
Park J, Shin YO, Choo HY.The propionylpromazine concentrations in plasma after intramuscular administration to horses were determined using gas chromatography with nitrogen-phosphorus detection. After hydrolysis by beta-glucuronidase/arylsulphatase, the parent drug and three metabolites were detected in urine. The metabolites were identified as 2-(1-hydroxypropyl)promazine, 2-(1-propenyl)promazine and 7-hydroxypropionylpromazine by gas chromatography-mass spectrometry. No N-demethylated or sulphoxidated metabolites of propionylpromazine were observed in the horse urine.
Ricci G, Del Boccio G, Pennelli A, Aceto A, Whitehead EP, Federici G.Glutathione transferase (EC 2.5.1.18) from horse erythrocytes has been purified and some molecular and kinetic properties have been investigated. It appears to be a dimeric protein composed of subunits of about 23 kDa, indistinguishable either in sodium dodecyl sulfate or in urea electrophoresis. Amino acid composition, substrate specificities, sensitivity to inhibitors, CD spectra, and immunological studies provide evidence that the horse enzyme is related to the pi class transferases. This enzyme has only two reactive thiol groups/dimer whose integrity appears to be essential for the activit...
Posnett ES, Ambrosio RE.This report describes DNA probes for the identification of Babesia equi. A genomic library of B. equi was constructed in pUC13. Several clones were identified that hybridized strongly to B. equi DNA. Clone pBE33 hybridized specifically to B. equi DNA and did not hybridize to horse DNA nor to DNA from Babesia caballi, Babesia bovis or Babesia bigemina. Two subclones of pBE33 (pSB20 and pEH21) containing B. equi repetitive sequences, could detect 0.49 ng and 0.97 ng B. equi DNA, respectively.
Liebler EM, Gerhards H, Denkhaus M, Pohlenz J.Infections with Micronema deletrix are described sporadically in humans and horses. This case report describes the infection with Micronema deletrix in a horse. The animal was sent to the clinic because of recurrent colic. On rectal palpation a mass was detected in the area of the right kidney and the horse was destroyed on its owners request. At slaughter a greatly enlarged right kidney interspersed with numerous white nodules was found. Histological examination revealed a granulomatous nephritis with numerous sections of nematodes. Based on their morphology and size, they were identified as ...
Lavoie JP, Spensley MS, Smith BP, Mihalyi J.Colostral volume and IgG and IgM concentrations were determined in 6 multiparous mares at foaling and them every 2 hours from 16 to 20 hours after parturition. Serum IgG and IgM concentrations at foaling also were determined in each mare. The rate of mammary secretion was 292 +/- 26 ml/h (range, 202 to 389 ml/h), and the colostral volume was 5.1 +/- 0.5 L (range, 3.2 to 7.0 L). The colostral IgG and IgM contents were 440 +/- 106 g (range, 199 to 855 g) and 3.1 +/- 0.9 g (range, 0.7 g to 7.1 g), respectively. There was no significant correlation between serum and initial colostral IgG and IgM c...
Moore JN, Allen D, Clark ES.This article reviews research findings relating to the pathophysiology of acute laminitis in horses. The data presently available suggest that the onset of the condition may be due to constriction of the postcapillary vessels in the digit, leading to increased capillary hydrostatic pressure and movement of fluid into the interstitial space.
Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Collins SS.A total of 59 equids (54 horses and five Shetland ponies) were treated with pyrantel pamoate once, at the dose rate of approximately 6.6 mg base kg-1, during the period November 1985-January 1988. The drug was administered as a paste formulation (51 equids) intraorally or as a suspension formulation by stomach tube (eight equids). The purpose of treatment was to evaluate the activity of pyrantel pamoate (at the therapeutic dose rate) for removal of the tapeworm, Anoplocephala perfoliata, by a modified (24-h) critical test. The presence or absence of tapeworms was not determined for the equids ...
Ducharme NG, Horney FD, Partlow GD, Hulland TJ.The purpose of this project was to adapt a surgical technique from humans and dogs to horses in which a portion of an accessory muscle of respiration and its nerve supply is transplanted to a denervated dorsal cricoarytenoid muscle. Anatomical dissections in seven horses revealed two possible donor nerve-pedicle grafts: the omohyoid and the sternothyrohyoid, both innervated by a branch of the first and second cervical nerves. Histochemical evaluations in two ponies of the dorsal cricoarytenoid, omohyoid and sternothyrohyoid muscles revealed similar proportions of fiber types 1 and 2 in all thr...
Coleman SU, Klei TR, French DD, Chapman MR, Corstvet RE.In 1985, 22 pony foals reared in a helminth-free environment were tested daily for oocysts of Cryptosporidium sp by use of fecal flotation. Oocysts were found in all foals. Oocysts were first observed in feces collected from foals 9 to 28 days after birth. The mean period of oocyst shedding was 10 days and ranged from 2 to 18 days in individual foals. Diarrhea was observed in 14 of 22 (64%) foals and began before the period of oocyst shedding. Fecal samples also were examined for other infective agents. Salmonella poona was isolated from 1 foal that did not have diarrhea, and coronavirus parti...
Kwong EC, Chen FC, Young LM.The urinary excretion of a sustained-release formulation of pentoxifylline was studied in the horse after the oral administration of 4.0 grams of Trental tablets. Urine samples were collected for 24 hours after dosing and analyzed for pentoxifylline and its metabolites using high-performance liquid chromatography coupled with an ultraviolet detector. Six metabolites of pentoxifylline were identified in horse urine in addition to less than 0.2% of unchanged drug. Concomitant use of gas chromatography/mass spectrometry allowed for the elucidation of the chemical structures of the metabolites. Me...
Shirakawa T, Ide M, Taniyama H, Tobiwatari K, Senba H, Oishi H, Matsui T, Ono T.A 1-month-old male thoroughbred foal, which had difficulty in walking, was killed and examined by histological, histochemical and ultrastructural methods. The muscles of the trunk and upper hind limbs were chiefly affected, and changes in the affected muscles resembled those in muscular dystrophy in man. The type of muscular dystrophy present in this foal and the significance of this disease in thoroughbred horses are discussed. The dystrophy in this foal resembled the limb-girdle type or myotonic dystrophy of muscular dystrophy in man.
Park RD.A complete radiographic examination of the equine foot consists of properly exposed, processed, and positioned radiographs. For radiographic interpretation, in addition to knowing radiographic signs of disease, a knowledge of normal radiographic anatomy and possible insignificant anatomic variations is necessary.
Murphy CJ, Lavoie JP, Groff J, Hacker D, Pryor P, Bellhorn RW.Bilateral swelling of upper and lower eyelids was caused by lymphocytic infiltration in an 8-year-old Thoroughbred mare. The condition worsened with pregnancy and became associated with subcutaneous dissemination of lymphosarcoma at distant sites.
Seahorn TL, Brumbaugh GW, Carter GK, Wood RL.Erysipelothrix rhusiopathiae serotype 5 was isolated from blood obtained antemortem from a horse with presenting problems of laminitis, uveitis, acute blindness, localized ventral edema and depression. The patient failed to respond to therapy and died 96 hours after the onset of clinical signs. Cultures of the lung postmortem yielded Erysipelothrix rhusiopathiae serotype 5, Beta-hemolytic Streptococcus sp., Escherichia coli, Proteus sp., and Klebsiella sp.
Ducharme NG, Viel L, Partlow GD, Hulland TJ, Horney FD.The purpose of this project was to attempt restoration of abduction of a recently denervated left dorsal cricoarytenoid muscle in the horse by anastomosing the first cervical nerve to the abductor branch of the left recurrent laryngeal nerve. Ten horses were used in the study. In six horses the left recurrent laryngeal nerve was transected and ligated while the ventral branch of the left first cervical nerve was anastomosed to the abductor branch of the left recurrent laryngeal nerve. The remaining four horses also had the left recurrent laryngeal nerve transected and ligated but had no nerve ...
Roser JF, Dudan F, Little TV, Livesay-Wilkins P, Hillman RB.Studies were undertaken to investigate the effects of oxytocin induction on prolactin release in term (Group II) and preterm (Group III) mares and to compare these effects to spontaneously foaling mares (Group I). Since physiological concentrations of prolactin in blood have not been measured in the neonatal foal, experiments were designed to monitor prolactin in the cord artery and jugular blood of the foals from all groups of mares. Although prolactin levels varied in term mares (Group I and II) during the last 11 days of pregnancy, an increase was observed between Day -6 and Day 0 (2.7 and ...
Weckman TJ, Tai CL, Woods WE, Tai HH, Blake JW, Tobin T.Pharmacologic effects of alpha-methylfentanyl and 3-methylfentanyl, analogs of fentanyl, were investigated in mares. The ability of an 125I-labeled fentanyl radioimmunoassay (125I-RIA) to detect these methylated fentanyl analogs in individual and pooled urine samples from horses was evaluated. Also, the ability of 7 fentanyl antibodies to react with fentanyl and fentanyl derivatives (sufentanil, alfentanil, and carfentanil) was investigated. Mares were studied in a locomotor test to determine the amount of stimulation methylated fentanyl analogs might induce. Two mares each were given alpha-me...
Stashak TS.The causes, clinical signs and various approaches to treatment of injuries involving the foot and pastern regions are reviewed, and the prognosis for each type of injury is discussed.
Gallivan GJ, Bignell W, McDonell WN, Whiting TL.Two simple nonrebreathing valves suitable for use with large mammals are described. These valves can be constructed in a reasonably well equipped workshop using materials that are readily available. The resistive pressure of both valves is less than 0.1 kPa at flow rates up to 15 L.s-1. Their main limitation is a relatively large dead space, although the dead space of valve B (290 mL) is less than the dead space of some commercially available valves. Healthy adult horses and cows compensate for the increased dead space by an increase in tidal volume.
Townsend WM, Langohr IM, Mouney MC, Moore GE.Based on the current literature, neither medical, surgical nor combination therapy adequately controls equine glaucoma for many horses. Aqueous shunts have been useful in other species to control glaucoma. Objective: To determine whether aqueous shunts in normal equine eyes significantly reduce intraocular pressure (IOP) without causing vision threatening complications. Methods: Prospective experimental trial. Methods: Aqueous shunts were placed in 7 normal eyes of 4 horses. The shunts were placed dorsotemporally. Examinations were initially performed daily for 7 days and after that every 3 da...
Gaynor JS, Bednarski RM, Muir WW.The effect of xylazine on the arrhythmogenic dose of epinephrine (ADE) was studied in 9 horses. Anesthesia was induced by administration of guaifenesin (50 mg/kg of body weight, IV) followed by thiamylal (4 to 6 mg/kg, IV) and was maintained at 1 minimal alveolar concentration (MAC) of halothane (0.89%). Base apex ECG and facial artery pressure were recorded. Epinephrine was infused in a sequence of arithmetically spaced increasing rates (initial rate 0.25 micrograms/kg/min) for a maximum of 10 minutes. The ADE was defined as the lowest epinephrine infusion rate to the nearest 0.25 micrograms/...
Thompson DL, Reville-Moroz SI, Derrick DJ, Walker MP.Sixteen intact cyclic mares were treated on the fourth day of estrus and then every other day for a total of six injections with 1) testosterone propionate, 2) dihydrotestosterone (DHT) benzoate, 3) estradiol (E2) benzoate or 4) safflower oil. Mares were given gonadotropin releasing hormone (GnRH) on Day 3 of estrus (pretreatment) and again 24 h after the last steroid or oil injection. Treatment with testosterone propionate resulted in a greater (P less than 0.05) follicle-stimulating hormone (FSH) response to the second injection of GnRH compared with all other treatments. Treatment with DHT ...
Afonso T, Giguère S, Rapoport G, Barton MH, Coleman AE.Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. Objective: To determine the cardiovascular effects of pimobendan in healthy mature horses. Methods: Randomised experimental study. Methods: Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses ...
Nap RC, Wouda W, Firth EC, Dik K, von Dijk P.The case of a horse affected with frontal sinusitis, in which neurological complications occurred following trepanation, is reported. The previous history of the animal as well as the clinical, radiological and pathological findings are discussed.
Bartmann CP, Stief B, Schoon HA.Transendoscopic thermal preparation techniques like laser- or electrosurgery have proved to be most reliable for minimal invasive intrauterine surgery during operative hysteroscopy in mares. To determine the effect of Nd:YAG laser surgery on the endometrium and the complete uterine wall compared with electrosurgery, standard lesions were obtained by transendoscopic monopolar electrosurgery (loop electrode, cutting blade) and Nd:YAG laser surgery (contact, bare fibre, 25 Watt, exposure time four seconds, non contact, 80 Watt, exposure time four seconds) in five healthy mares on days d 0, 7, 14,...
Harrison S.While the importance of religious and magical healing practices in the Late Middle Ages is well established, the ritual aspects of veterinary medicine have so far not been thoroughly explored. This article addresses this lacuna through analysis of a corpus of charms, prayers, and other rituals that were used to cure a group of devastating contagious diseases that afflicted horses: animals that were often afforded complex, professional medical care in this period. It considers the semantic aspects and common features of this group of disease rituals alongside discussions of contagious illness i...
Sertich PL, Pozor MA, Meyers SA, Brown JS.A 9-year-old Thoroughbred stallion was examined because of breeding dysfunction and possible urethritis. The stallion had good libido and readily obtained an erection, mounted, and intromitted but did not thrust and ejaculate. After mounting the mare, the stallion would squeal and dismount. Endoscopic examination of the urethra and bladder revealed irregular, spiculate yellow crystals (< 1 cm in size) and sabulous deposits; numerous calculi were embedded in the mucosa of the bladder. Because the horse was at the start of a breeding season, the owner would not give permission for general anesth...
Brabon A, Labens R, Ramachandran A, Dart AJ, Dowling BA.Four adult horses with histories of moderate abdominal pain and inappetence were diagnosed with delayed gastric emptying and gastric impaction attributed to pyloroduodenal obstruction (three cases) or duodenitis (one case). A stapled side-to-side gastrojejunostomy was performed on all horses. Two horses returned to work and survived ≥3 years. One horse was euthanased 6 months post-surgery due to recurrent abdominal pain, and one was found dead 5 months postsurgery after an unattended foaling.
Still J.This study reports on clinically significant relief of pain along the gall bladder meridian in 15 sport horses. Both local and distant points were needled in this study. Pain relief was marked not only locally but also in remote areas along the gall bladder meridian. Clinical improvement was observed in all 15 horses within 30 seconds to 2 minutes after the treatment had started. Twelve horses and three horses were rated as "cured" and "improved", respectively, when they were re-examined 1-8 days after the treatment. The relief of somatic pain was often associated with improved riding perfor...
Devine DV, Jann HW, Payton ME.To assess gait abnormalities associated with selective anesthesia of the suprascapular nerve (SSN) achieved by use of perineural catheterization and thereby determine the function of that nerve as it relates to gait in horses. Methods: 3 adult horses with no preexisting clinically apparent lameness at a walk. Methods: Each horse was anesthetized; the right SSN was exposed surgically for placement of a perineural catheter to permit delivery of 1 mL of 2% mepivacaine hydrochloride. Six hours after recovery from anesthesia, each horse was videotaped while walking (50-step data acquisition period)...
Newman MJ, Beegle KH, Antczak DF.Monoclonal antibodies to equine lymphocyte antigens were produced, using normal peripheral blood lymphocytes as the immunogen and standard hybridoma techniques. Antibody producing hybridomas were detected by a solid-phase enzyme-linked immunosorbent assay. Antibodies produced by 6 cloned hybrids were characterized further by microlymphocytotoxicity, indirect immunofluorescence, and agglutination assays on peripheral blood lymphocytes, platelets, and erythrocytes. Reaction patterns on leukocytes indicated that these antibodies may recognize at least 3 different cell-surface antigens: (1) an ant...
Pollock RV.Advances in digital technology have vastly increased the speed and content of information transfer. Equine practitioners of the future should be in contact with their office and other information resources at all times through an array of digital networks. Patients and practitioners alike should benefit from better information access.
Harkins JD, Mundy GD, Stanley S, Woods WE, Boyles J, Arthur RA, Sams RA, Tobin T.Plasma and urinary concentrations of procaine and the duration of response to procaine after its administration as a local anaesthetic to horses were studied. Following injection of a clinical dose of procaine HCl (80 mg), the concentration of procaine in plasma was less than the lower limit of quantitation and unsuitable for threshold determination. Therefore, the urinary concentration of procaine was determined after injection of a dose of 5 mg procaine HCl, the highest no-effect dose (HNED) of this agent. Free unconjugated procaine in equine urine reached a peak concentration of 23.7 ng/mL,...
Palmer JE.Cardiac arrest in foals is generally secondary to other serious systemic diseases. Although it can often be anticipated, a clear plan is vital to success. Establishing cardiac output through chest compressions is the most important first step. This step should be followed by ventilation, drug therapy, identifying the nonperfusing cardiac rhythm, and following a preplanned treatment algorithm. Birth resuscitation requires special treatment considerations. The clinician should be prepared to perform resuscitation any time a birth is attended.
Klonisch T, Ryan PL, Yamashiro S, Porter DG.To determine the site of relaxin gene expression in equine placentae, a set of degenerate oligonucleotide primers was made according to the published amino acid sequence of the A- and B-chain of equine relaxin (eRXN). Total cellular RNA (tcRNA) from equine placentae at about 120 and 300 days of pregnancy was subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) with use of these primers. A single amplification product of approximately 430 bp was detected in each case by agarose gel electrophoresis. The PCR product was ligated into Bluescript plasmid and sequenced to confirm the...
Nelson BB, Lawless SP, McIlwraith CW.Characteristics and outcomes after surgical repair of third carpal bone (C3) slab fractures involving both radial and intermediate facets in racing Quarter Horses are unknown. Objective: To describe the pre- and intraoperative characteristics of C3 slab fractures of both radial and intermediate facets in Quarter Horses and to report on the long-term outcomes after internal fixation. Methods: Retrospective case series. Methods: Case records were collected from racehorses with C3 slab fractures between 2008 and 2020. Inclusion criteria required arthroscopic-guided repair of C3 slab fractures inv...