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.
Dawson JE, Abeygunawardena I, Holland CJ, Buese MM, Ristic M.Eight adult cats were inoculated IV (n = 6) or SC (n = 2) with Ehrlichia risticii-infected P388D1 (continuous murine macrophage) cells or with E risticii released from P388D1 cells. Three additional cats were inoculated with organism-free P388D1 cultured monocytes, and 1 cat, which served as a medium control was inoculated with balanced salt solution. Clinical signs of illness were observed in the IV inoculated cats from which E risticii was isolated. One cat developed intermittent diarrhea between postinoculation days (PID) 8 and 18, and the other cat developed lymphadenopathy, acute depressi...
Schumacher J, Vaughan JT.Treatments of penile and preputial injuries, anomalies, tumors, "summer sores," paraphimosis, phimosis, and priapism are presented. Surgical procedures described include preputiotomy, reefing, penile retraction, amputation, and relocation. Treatment of hemospermia by means of urethrotomy is discussed.
Johnson JE, Beech J, Saik JE.A 6.5-year-old horse with a history of exercise-induced pulmonary hemorrhage was admitted because of acute onset of epistaxis, dyspnea, high respiratory rate, pale mucous membranes, and dark feces. There was no clinical or laboratory evidence of a bleeding disorder, and the horse's anemia was considered to be secondary to pulmonary hemorrhage. The cause of the hemorrhage was not found on thoracic sonograms or from cytologic examination of transtracheal aspirates. Despite supportive care, the horse's health deteriorated, and it was euthanatized. Necropsy revealed blood in the thoracic and perit...
Kozawa Y, Mishima H, Sakae T.During the evolution of the Equoidea, the histological structures of the teeth have become more complex as the molars have become hypsodont in form. The straight Hunter-Schreger bands of Hiracotherium have evolved into a more complex pattern in Equus. The enamel prisms changed from an arched form (about 5μm in diameter) with an alternating pattern in Hiracotherium to an oval form (about 2 μm width) arranged in straight rows in Equus. In Equus the rows of prisms are separated by interprismatic sheets. This pattern may have increased the architectural strength of the enamel, and is related to ...
King JN, Gerring EL.Dopamine was infused intravenously (1, 5 and 10 micrograms/kg/min) for 60 min in three fasted ponies. A dose-dependent increase in heart rate occurred that was rapid in onset and termination at the start and end of the infusions, respectively. Dose-dependent changes in gastric and small intestinal motility were observed. An initial marked inhibition of gastric contraction amplitude was followed by a secondary prolonged period of activity. At the same time the small intestine showed a prolonged period of irregular activity (phase II) and a marked increase in the interval between successive phas...
Humber KA, Sweeney RW, Saik JE, Hansen TO, Morris CF.Bacillus piliformis infection (Tyzzer's disease) in foals is rarely observed clinically because of the peracute course of the disease. Clinical and clinicopathologic findings as well as information on therapeutic attempts in two foals are described. Clinicopathologic abnormalities common to both cases included leukopenia, hyperfibrinogenemia, metabolic acidosis, and hypoglycemia. Treatment was unsuccessful in both cases.
Dennis VA, Klei TR, Chapman MR, Jeffers GW.Eosinophils and neutrophils from ponies with Strongylus vulgaris-induced eosinophilia (eosinophilic ponies; activated eosinophils and neutrophils) were assayed in vitro for chemotactic and chemokinetic responses to zymosan-activated serum (ZAS) using the filter system in Boyden chambers, for Fc and complement (C) receptors using the EA and EAC-rosette assays, respectively, and for phagocytic and bactericidal activities using opsonized Escherichia coli and the acridine orange method. The responses of activated eosinophils and neutrophils in the above assays were compared with those of eosinophi...
Jacob RJ, Steiner MR.Equine herpesvirus 3 (EHV-3)-infected equine cells display a kinetics of infected cell polypeptide (ICP) synthesis at 34 degrees C that is typical of coordinate cascade gene regulation of herpesviruses. In contrast, when infected cell cultures are incubated at the restricted temperature of 39 degrees C, the shift from early (beta) gene expression to late (gamma) gene expression is perturbed, i.e., there is an accumulation of early (beta) gene products and a decrease in, or absence of, late (gamma) gene products. Some of the affected late (gamma) gene products may be glycoproteins since these I...
Tobin T, Watt DS, Kwiatkowski S, Tai HH, Blake JW, McDonald J, Prange CA, Wie S.We have introduced large scale non-isotopic immunoassay testing into pre- and post-race drug testing in racehorses. The technologies utilized are Particle Concentration Fluorescence Immuno Assay (PCFIA) and the one-step Enzyme Linked Immuno Sorbent Assay (ELISA). These technologies are rapid, inexpensive, and highly effective. On introduction into post-race testing in the Western United States, these ELISA tests exposed several previously undetected patterns of drug abuse. The drugs detected were buprenorphine, oxymorphone, mazindol, sufentanil and cocaine. This led to the suspension of a larg...
Trotter GW, McKinnon AO.Reproductive failure in mares can present a challenge to the attending veterinarian. Although many causes of failure to conceive or to carry to term may be easy to diagnose and treat effectively, others may be difficult. In some cases, more than one problem will be present, and both medical therapy and surgical intervention will be required to achieve a successful outcome. Pneumovagina and its sequelae remain a common cause of reproductive failure in mares. Depending on the case involved, different surgical techniques may be required to correct the problem.
Slocombe JO, Cote JF.Twenty horses were treated with ivermectin either by nasogastric tube with a liquid formulation for sheep or per os with a paste formulation for horses at a dosage of 200 mug/kg of body weight. Fecal samples were collected from these horses and from ten untreated horses at the time of treatment and every 2 wk thereafter for up to 10 wk. The samples were examined for nematode eggs using the Cornell-McMaster dilution and the Cornell-Wisconsin Double Centrifugation procedures.There were no signs of toxicosis in horses treated with ivermectin. Strongyle eggs were found in the feces of all horses b...
Wilson WD, Spensley MS, Baggot JD, Hietala SK.The pharmacokinetics and bioavailability of rifampin were determined after IV (10 mg/kg of body weight) and intragastric (20 mg/kg of body weight) administration to 6 healthy, adult horses. After IV administration, the disposition kinetics of rifampin were best described by a 2-compartment open model. A rapid distribution phase was followed by a slower elimination phase, with a half-life (t1/2[beta]) of 7.27 +/- 1.11 hours. The mean body clearance was 1.49 +/- 0.41 ml/min.kg, and the mean volume of distribution was 932 +/- 292 ml/kg, indicating that rifampin was widely distributed in the body....
Bertone JJ, Traub-Dargatz JL, Wrigley RW, Bennett DG, Williams RJ.Four horses with diarrhea had radiographic evidence of large quantities of sand in the gastrointestinal tract. Initially, none of the horses had sufficient fecal sand quantity to suggest sand enteropathy. Diarrhea resolved in all horses within 2 days of oral administration of psyllium hydrophilic mucilloid. Historically, all 4 horses had lost weight or had difficulty maintaining weight. After treatment was administered, the horses either gained weight or were easier to maintain in good condition.
Karabatsos N, Lewis AL, Calisher CH, Hunt AR, Roehrig JT.A virus, strain 64A-1519, isolated from the brain of a horse dying of encephalitis in Florida in 1964, was identified as western equine encephalomyelitis (WEE) virus. Recently, we used polyclonal and monoclonal immune reagents to identify this isolate by comparing it to 2 strains of WEE virus and to Highlands J (HJ) virus in hemagglutination-inhibition, immunofluorescent antibody, and plaque-reduction neutralization tests. These tests demonstrate that strain 64A-1519 is a strain of HJ virus distinct from WEE virus.
King JN, Gerring EL.The effect of cisapride was evaluated on the normal fasting bowel motility of four ponies with chronically implanted electromechanical transducers. Cisapride was infused over 60-min periods at 0.05 mg/kg (n = 4), 0.1 mg/kg (n = 5) and 0.25 mg/kg (n = 5). It produced marked and prolonged increases in electrical and mechanical activity at all sites examined. In the stomach there was increased total contraction activity with increased contraction amplitude and a slight reduction in rate. In the small intestine there was an increase in irregular (phase II) activity with an increase in number and a...
Green SL, Specht TE, Dowling SC, Nixon AJ, Wilson JH, Carrick JB.A neonatal foal was examined because of apparent abdominal pain and distention, anemia, and hemoperitoneum. Exploratory laparotomy was performed, and a large spherical mass, which had ruptured, was found in the area of the left ovary. Left salpingo-oophorectomy was performed. The mass was determined to be a juvenile granulosa cell tumor.
Ebisawa I, Takayanagi M, Kigawa M.Clostridium tetani was isolated from human and animal stools at the following rates [95% confidence interval (CI)]: Human, 0% (1.5-0); horse, 1% (5-0); cow in cowshed, 4% (10-1); cow in pasture, 8.3% (17-1), calf in pasture, 0% (7-0); dog, 2% (11-0) and sheep in pasture, 25% (44-14). Quantification of C. tetani in 16 animal stools positive for the bacillus was impossible in most cases, as the number of tetanus bacilli present was not large enough for this purpose. Contaminating anaerobic and facultative anaerobic bacteria in human and animal stools, i.e., C. perfringens and Streptococcus sp., ...
Broadstone RV, Scott JS, Derksen FJ, Robinson NE.The effects of atropine on lung function and airway reactivity in two groups of ponies were measured. Principal ponies had a history of recurrent airway obstruction when housed in a barn and fed hay; control ponies had no history of airway obstruction. Principal and control ponies were paired, and measurements were made when principal ponies were in clinical remission (period A) and during an acute attack of airway obstruction (period B). Atropine did not alter pulmonary resistance (RL), dynamic compliance (Cdyn), or airway responsiveness in either group of ponies at period A or in the control...
Marasas WF, Kellerman TS, Gelderblom WC, Coetzer JA, Thiel PG, van der Lugt JJ.Each of two horses was dosed by stomach tube with culture material on maize of Fusarium moniliforme MRC 826. One horse developed severe hepatosis and mild oedema of the brain after 6 doses of 2.5 g of culture material/kg body mass/day in 7 days. The second horse, in a similar experiment but at a dosage rate of 1.25 g/kg/day, developed mild hepatosis and moderate oedema of the brain. In both animals the brain oedema was particularly noticeable in the medulla oblongata. The mycotoxin fumonisin B1 was extracted and purified from the culture material of F. moniliforme MRC, 826 which contained appr...
Robertson JT, Embertson RM.Surgical management of various congenital and perinatal abnormalities of the urogenital tract are discussed, including ruptured bladder, ruptured urachus, ureteral defect, patent urachus and umbilical remnant infection, ureteral ectopia, congenital inguinal hernia, and atresia ani and rectourethral or rectovaginal fistula.
Nickels FA.This article discusses the complications of castration and ovariectomy and their treatment and prevention. These two procedures were chosen because castration is the most common surgical procedure performed by the equine practitioner and ovariectomy is associated with a high number of complications.
Traub-Dargatz JL, McKinnon AO.Included in this article are descriptions of adjunctive methods of examination of the urogenital tract, including ultrasonography of the kidneys, urinary bladder, ovaries and uterus; endoscopy of the urethra, urinary bladder, and uterus; contrast radiography of the urinary tract; kidney biopsy; and laparoscopy of the abdomen, emphasizing examination of the mare's reproductive tract.
Trotter GW.Surgical exploration of the horse that has presumably had a normal castration or a previously successful cryptorchid surgery remains a distinct challenge. No hard and fast rules dictate a proper course of action for each case. If a horse was anesthetized for routine castration, discovered to have only one scrotal testis, had a brief exploratory on the nondescended side and was recovered, trauma to the inguinal region would probably be sufficiently minimal that an inguinal approach could be used at subsequent exploratory surgery. If the inguinal canal was extensively manipulated and the tail of...
Pozor MA, Benson SM, Macpherson ML, Kelleman AA.Transplantation of stem cells into dysfunctional testes is currently being investigated as a therapeutic option for men and stallions with advanced testicular degeneration. This series of "proof of concept" studies aimed to identify a safe and efficient method of inducing severe testicular degeneration to create an optimal equine recipient model for intratesticular stem cell transplantation (SCT). Two ex vivo and two in vivo experiments were conducted. At first, forty testes obtained from castrations were used to identify an effective therapeutic ultrasound (TUS) device and the protocol for ...
Hanson RR, Nixon AJ, Gronwall R, Meyer D, Pendergast J.Postoperative abdominal fluid changes were compared in 2 groups of horses; those undergoing double small-colon resection and anastomosis (n = 10) and those undergoing exploratory celiotomy alone (n = 5). Peritoneal fluid was collected before surgery and on postoperative days 1, 3, 5, and 7. Total and differential nucleated cell counts, RBC numbers, and total protein and fibrinogen concentrations were evaluated. In both groups, all values were significantly higher than normal on the first postoperative day (after small-colon resection and anastomoses, WBC = 130,350 +/- 23,310 cells/microliters,...
Davis JL, Kruger K, LaFevers DH, Barlow BM, Schirmer JM, Breuhaus BA.Angiotensin converting enzyme (ACE) inhibitors improve survival and quality of life in human patients and small animals with cardiovascular and renal disease. There is limited information regarding their effects in horses. Objective: The purpose of this study was to determine the pharmacokinetics of quinapril and its effects on ACE and renin in horses. Methods: Experimental study using healthy mature horses. Methods: Six healthy horses were administered quinapril at 120 mg i.v., 120 mg per os and 240 mg per os in a 3-way crossover design. Blood was collected for measurement of quinapril ...
Williams PF, Brooks SP, Cooper DR.Sir, — We wish to report the death of a foal due to a parasitic lesion caused by Parascaris equorum..P equorum is reported to cause periodic colic, enterilis, obstructive colic with occasional rupture of the small intestine. However, personal communications with other veterinarians and our experience indicate fatal cases are not as common as indictaed in the literature.
Rahmani Shahraki A, Raisi A.One of the reasons of weight loss and poor performance in horses is decrease in food intake. Oral cavity problems can cause malfunctions in prehension and deglutition resulting in dysphagia. There are few published reports about a metallic foreign body disorders in the oral cavity of horses due to an important role of their flexible lip and incisor teeth in food selection and prehension. This report describes the history, clinical, hematological and radiographic findings and surgical management of a left oral wall fistula formation due to a piece of wire penetration in a pregnant mare. The wir...
Gysens L, Depuydt E, Patruno M, Haspeslagh M, Spaas JH, Martens A.Sarcoids are the most common equine skin tumours Although they do not metastasize, they can be locally aggressive and cause significant clinical symptoms in affected horses. Despite being common, very little is known about the host immune response and the biological mechanisms underlying persistence and recurrence of equine sarcoids. The latter reflects the need for further research in this field. This in-vitro study used sarcoid explants from horses with naturally occurring sarcoids (n = 12) to evaluate the induction of a humoral immune response directed against equine sarcoid-derived bovin...
Poppie MJ, McGuire TC.Foals with combined immunodeficiency (CID), a fatal genetic defect in the production of both B and T lymphocytes, are born without immunoglobulins and are unable to synthesise them. CID foals receiving immunoglobulins via the dam's colostrum may live up to four months of age. Those CID foals with failure of passive transfer (FPT) die at a much earlier age. The occurrence of CID is of value in studying passive transfer of immunoglobulins, as no confusion exists as to when passive transfer ends and active synthesis of immunoglobulins begins. A high correlation has been found between early foal d...
Van Hoogmoed LM, Snyder JR, Nieto J, Harmon FA.To determine whether a customized solution could attenuate the effects of low-flow ischemia and reperfusion injury of the equine jejunum. Methods: A segment of jejunum obtained from 21 healthy adult horses. Methods: A segment of jejunum was maintained in an isolated extracorporeal circuit, and arterial flow was reduced to 20% of baseline for 40 minutes (ischemia) followed by 60 minutes of reperfusion. In 1 group, a customized solution was infused at a rate of 1 ml/min during low-flow ischemia and 3 ml/min during reperfusion. In a second group, the solution was infused at the same rate during l...
Akinboade OA, Awani O, Best O, Cole T.Summary Twelve (12) heavy horses of the Shire breed imported into Nigeria in 1974 died within two months after importation. This was because of inclement weather and non-availability of AHS vaccine.
Spoormakers TJ, Donker SH, Ensink JM.The anaesthetic potency, onset of action, duration of action, and side effects of lidocaine and lidocaine plus epinephrine for proximal metacarpal block of the lateral and medial palmar nerves were determined. Ten horses were used and legs were injected using a cross-over model with three test solutions: 1) solvent and lidocaine (2%) plus epinephrine (SLE); 2) solvent and lidocaine (2%) without epinephrine (SL); and 3) solvent only (S). The contra-lateral leg was injected with saline (placebo; P). In both the SL and SLE groups, the onset of anaesthesia occurred between 5 and 15 minutes after i...
van Zadelhoff C, Ehrle A, Merle R, Jahn W, Lischer C.Scintigraphy is a standard diagnostic method for evaluating horses with back pain due to suspected thoracic processus spinosus pathology. Lesion detection is based on subjective or semi-quantitative assessments of increased uptake. This retrospective, analytical study is aimed to compare semi-quantitative and subjective methods in the evaluation of scintigraphic images of the processi spinosi in the equine thoracic spine. Scintigraphic images of 20 Warmblood horses, presented for assessment of orthopedic conditions between 2014 and 2016, were included in the study. Randomized, blinded image ev...
Schamhardt HC, Merkens HW.A method was developed to quantify the ground reaction force pattern of the horse. A number of selected force amplitudes and peak-time positions in the normalized stance phase of left and right contralateral limbs were used to calculate symmetry indices. Data from each limb were compared with those of a 'standard horse' resulting in limb indices. The combination of amplitude and peak-time symmetry and limb indices yielded one H(orse)INDEX. These indices were useful for comparison of different horses and for the evaluation of lameness and treatment.
Foreman JH, Waldsmith JK, Lalum RB.Three-day event horses are subject to various external environmental stresses including changes in ambient temperature, humidity, altitude, and test severity. Considerable research on the adverse effects of increased heat and humidity preceded the 1996 Olympic Summer Games in Atlanta, Georgia USA, but no research has been done previously on the effects of altitude on 3-day eventing. Physical and venous blood gas data were collected on horses (n = 24) competing in the High Prairie Preliminary (CCN*) and Intermediate (CCN**) 3-day events and Preliminary Horse Trials in Parker, Colorado (1900 m a...
The Veterinary recordSeptember 9, 2017
Volume 181, Issue 10 ii doi: 10.1136/vr.j4128
Carslake H.Harry Carslake, equine medicine specialist at the Philip Leverhulme Equine Hospital, Liverpool, reviews a fiveday course on advanced cardiac ultrasound scanning that he completed recently.
Folz SD, Hanson BJ, Griffin AK, Dinvald LL, Swerczek TW, Walker RD, Foreman JH.Ceftiofur sodium was evaluated as a therapy for respiratory infections in horses. This cephalosporin antimicrobial was administered intramuscularly every 24 h and at a dose of 2.2 mg/kg (1.0 mg/lb) of body weight. The efficacy of ceftiofur sodium was compared with that of a positive control drug, ampicillin sodium (recommended dose of 6.6 mg/kg [3 mg/lb], given every 12 h). Both treatments were continued for 48 h after clinical symptoms were no longer evident (maximum of 10 days). Fifty-five (55) horses with naturally acquired respiratory infections were included in the study; 28 were treated ...
Houpt KA, Northrup N, Wheatley T, Houpt TR.When a preliminary experiment in sodium-replete ponies revealed an increase, but not a significant increase, in salt consumption after furosemide treatment, the experiment was repeated using sodium-deficient horses in which aldosterone levels might be expected to be elevated to test the hypothesis that a background of aldosterone is necessary for salt appetite. Ten Standardbred mares were injected intravenously with furosemide or an equivalent volume of 0.9% sodium chloride as a control to test the effect of furosemide on their salt appetite and blood constituents. Sodium intake and sodium los...
Gomez-Villamandos R, Santisteban J, Ruiz I, Avila I.Two horses with fibrotic myopathy of the semitendinosus muscle are described. The report deals with the aetiology, clinical signs and diagnosis of the condition, and discusses the different surgical techniques described in the literature. Tenotomies were performed on both horses. Excellent results were obtained in the horse in which only the semitendinosus muscle was affected, but in the horse in which the semimembranosus and gracilis muscles were also involved the results were less satisfactory.
Jones MB, Gonzalez-Ochoa A, Marx MB, Furcolow ML.In a 3-month period, 2,221 Mexican horses were skin tested for sensitivity to Histoplasma capsulatum antigen. The prevalence of reactivity was 7.9%. There was little evidence of a difference in geographic distribution of sensitivity. The prevalence of reactivity increased with age of the horse. This increment with age is thought to be a function of time exposure to the organism and possibly of selective survival of the horses.
Magnuson NS, Decker DM, Perryman LE.1. Activities of S-adenosylhomocysteine (AdoHcy) hydrolase were measured in tissues of horses with severe combined immunodeficiency. No decrease in activity of the enzyme was detected.
2. The activity in erythrocytes was 14.2 ± 9.2 nmol AdoHcy formed/min/g hemoglobin and in fibroblasts it was 28.0 ± 7.9 nmol AdoHcy formed/min/108 cells.
3. Km values were obtained for hemolysates (0.77 μM) and for fibroblast lysates (0.59 μM).
4. Effects of 2′-deoxyadenosine on enzyme inactivation were studied.
White R, Nath L, Hebart M, Franklin S.P wave indices are used as non-invasive electrocardiographic markers of atrial remodelling in humans. Few studies have investigated their use in animals. The aim of this study was to measure P wave duration and P wave dispersion (Pd) in healthy standardbred horses and investigate variables that might influence these measurements. A 12-lead electrocardiogram was recorded at rest and P wave indices were calculated in 53 horses. A general linear model was used to investigate the main effects: age, bodyweight, sex, resting heart rate, presence of a murmur, exercise status and the number of years r...
Fatemi-Nainie S, Anderson LW, Cheevers WP.MC-1 is an equine sarcoid-derived cell line which spontaneously releases a retrovirus possessing genomic sequence homology with an inducible endogenous retrovirus of normal equine cells. A complete characterization of MC-1 tumor cells was undertaken, including morphology, growth kinetics, and saturation density, selective growth in semisolid media, uptake of 2-deoxyglucose, and tumorigenicity in athymic nude mice. MC-1 cells, in contrast to normal equine dermal fibroblasts, exhibit all of the characteristics of malignantly transformed cells.
Visser HE, Diehl KA, Whitley RD, Myrna KE.To compare Schirmer tear test I (STTI) values collected in normal horses with and without an auriculopalpebral nerve block. Methods: Schirmer tear test I values were measured in 20 clinically normal horses (38 eyes) with a median age of 12 years. The order of eyes tested was randomized. Within 24-48 h, at the same time of day, tear measurements were collected again after administration of an auriculopalpebral nerve block. Each block was performed a minimum of 5 min prior to each STT I. A repeated-measures model was used to analyze differences between STT I values in eyes with and without nerve...
