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.
Matthews NS, Gleed RD, Short CE, Burrows K.Isoxsuprine (0.6 mg/kg) administered IV to 6 standing horses produced substantial, transient decreases in systemic blood pressure, systemic vascular resistance, and stroke volume. It also produced substantial, transient increases in heart rate, cardiac output, and purposeful movement. Plasma concentrations of isoxsuprine peaked soon after the drug was administered IV and then decreased over a 12-hour period in a biexponential manner, with distribution and elimination half-lives of 14 minutes and 2.67 hours, respectively. Total body clearance and steady-state volume of distribution were calcula...
Takai S, Iimori S, Tsubaki S.Quantitative culture of Corynebacterium (Rhodococcus) equi from feces of 17 foals on a farm (A) with an endemic C. equi infection problem and 26 foals on a farm (B) without the disease in the past decade was done with a selective medium at weekly or monthly intervals from April to August of 1984. Corynebacterium equi was observed in the feces of 16 of 17 foals on farm A, and 19 of 26 foals on farm B. The mean viable count of C. equi in one gram of feces was 4.1 +/- 3.7 (log10) on farm A, and 3.9 +/- 3.4 (log10) on farm B. Corynebacterium equi was recovered from feces of foals as young as two w...
Cole JR, Hall RF, Gosser HS, Hendricks JB, Pursell AR, Senne DA, Pearson JE, Gipson CA.A group of 14 pregnant mares was exposed via contact to 4 mares bred to stallions infected with equine viral arteritis virus. There was a demonstrable febrile response in each donor mare and in 12 of the pregnant mares. All 18 mares became seropositive after exposure. Equine viral arteritis virus was isolated from the nasopharynx of 5 pregnant mares, but not from the donor mares. Ten of the pregnant mares aborted, and virus was isolated from fetal specimens or placenta of 8.
Pan LG, Forster HV, Kaminski RP.We assessed in ponies the adequacy of using rectal (Tre) rather than arterial temperature (Tar) under conditions common to ventilatory control experiments, i.e., CO2 breathing, thermal stress, and particularly exercise. We were interested in whether, and to what extent, Tar-Tre differences could lead to errors in arterial blood gas corrections. At control environmental temperatures (Ta) of 5 degrees C in the winter and 21 degrees C in the summer, Tar and Tre (37.1 degrees C) did not differ (P greater than 0.05). Elevating winter or summer Ta by 10-18 degrees C for 2-days or lowering summer Ta ...
Cozzi B.A combined ultrastructural and immunocytochemical study was performed on the pineal gland of the horse in order to identify the cell types present and describe their characteristics. Comparisons have been made with other mammals. Two main cell types are present: pinealocytes and glial cells. Pinealocytes display different degrees of electron density in the nucleus and the cytoplasm, yet no ultrastructural feature supports the idea of separate populations. Putative secretory materials are stored in vesicles related to the Golgi apparatus. A variety of electron-dense bodies are present in the cy...
Glade MJ.In an attempt to validate the use of urinary creatinine concentration as an index of urinary flow rate, a series of timed quantitative urine collections were done on several groups of weanling and yearling ponies and Thoroughbreds. A total of 411 urine samples were generated by 19 ponies and 12 Thoroughbreds. Urinary flow rates and urinary creatinine concentrations were measured. When all the data were examined, urinary flow rates were independent of creatinine concentrations. However, for any given animal, daily urinary creatinine excretion was constant over several days, and urinary creatini...
Cahill JI, Goulden BE.This light microscopic investigation of 15 Thoroughbred horses provided substantial evidence for the classification of equine laryngeal hemiplegia as a distal axonopathy. Morphologic and morphometric examinations were performed on resin embedded recurrent laryngeal nerves from control, subclinical and clinical laryngeal hemiplegic animals. In the latter group of animals some distal hindlimb nerves were also examined. A distally graded loss of myelinated fibres selectively affecting those of large diameter was demonstrated in both left and right recurrent laryngeal nerves. Morphologic evidence ...
Hill T, Carmichael D, Maylin G, Krook L.The incidences of fractures and soft tissue injuries during 68397 starts of thoroughbred horses at New York Racing Association tracks were analyzed concerning track condition, dirt and turf tracks, environmental conditions, length of races, location of fractures on the track, and age of horses. It was concluded that the conditions evaluated are of no importance in the occurrence of racing injuries to thoroughbred horses.
Allen D, White NA, Tyler DE.Twenty horses with small intestinal obstructions requiring surgery were evaluated prospectively. Ten horses lived (group 1) and 10 died (group 2). Eight of the horses in group 1 had simple obstruction and 7 of the horses in group 2 had strangulation obstruction. There was a significant difference (P less than 0.001) between the mean intraluminal hydrostatic pressure in horses of groups 1 and 2 (6.3 cm H2O and 15 cm H2O, respectively). The mean peritoneal fluid protein concentration in horses of groups 1 and 2 (2.8 mg/dl and 5.4 mg/dl, respectively) also differed significantly between groups (P...
Patel J, Lofstedt RM.This report involves uterine rupture in a mare, which was unique because it was not associated with assisted or difficult foaling. We describe an alternative to surgical correction of the condition and illustrate the need for luminal uterine palpation, so that uterine rupture does not go undiagnosed.
Himmler A, Hauptmann R, Adolf GR, Swetly P.Using human interferon-alpha 2 (IFN-alpha 2) and IFN-beta DNA to probe an equine genomic library we isolated recombinant phages containing genes for equine interferon-alpha (EqIFN-alpha), interferon-beta (EqIFN-beta), and interferon-omega (EqIFN-omega). Sequence and hybridization analyses of these genes reveal that the equine genome contains gene families of each of these three type I interferon classes. The mature proteins of EqIFN-alpha are 71-77% homologous to human IFN-alpha polypeptides, and, when expressed in E. coli, possess antiviral activity on both equine and human cells. By contrast...
Byars TD, Greene CE, Kemp DT.Warfarin-induced anticoagulation and reversal of the induced anticoagulation by vitamin K1 were evaluated in 4 mature horses. Each horse was given warfarin IV until the prothrombin (PT) time was prolonged by approximately 1.5 times the predosing base-line value. In experiment 1, we evaluated the time required for PT to return to the predosing value (PT reversal time) after warfarin administration was discontinued. Between each experiment, a 1-week rest period was allowed. In experiment 2, two doses of vitamin K1 (100 mg/dose) were administered IM 6 hours apart, and the PT was monitored hourly ...
Dumasia MC, Houghton E, Moss MS, Chakraborty J, Marks V.The pro-drugs of dexamethasone, a potent glucocorticoid, are frequently used as anti-inflammatory steroids in equine veterinary practice. In the present study the biotransformation and urinary excretion of tritium labelled dexamethasone were investigated in cross-bred castrated male horses after therapeutic doses. Between 40-50% of the administered radioactivity was excreted in the urine within 24 h; a further 10% being excreted over the next 3 days. The urinary radioactivity was largely excreted in the unconjugated steroid fraction. In the first 24 h urine sample, 26-36% of the total dose was...
White NA, Suarez M.Triceps intracompartmental pressure was measured in the lowermost limb of the recumbent horse during the initial period of recumbency during elective surgical procedures in 11 horses. Intramuscular pressure, using an IM catheter, was measured with the thoracic limbs in 4 different positions, including (I) table-contact limb unadvanced-unsupported free limb, (II) table-contact limb unadvanced-supported free limb, (III) table-contact limb advanced cranially, unsupported free limb, and (IV) table-contact limb advanced cranially, supported free limb. Pressure was measured in the 4 positions with a...
Hardy J, Marcoux M, Eisenberg H.A suspected lesion of osteochondrosis dissecans involving the anconeal process of the humeroradial joint (elbow) was found in 2 horses. In horse 1, the lesion was found during routine lameness examination, during which alleviation of the lameness was achieved after intra-articular anesthesia of the elbow. In horse 2, the lesion was found at necropsy. Horse 1 responded satisfactorily to intra-articular treatment with hyaluronic acid. Both horses also had other joints affected with osteochondrosis dissecans.
Carter GK, Martens RJ, Brown SA, Martin MT.Pharmacokinetic values of sodium amoxicillin (22 mg/kg of body weight) in foals were determined after a single IM injection in 6 Quarter Horse foals at 3, 10, and 30 days of age. Serum amoxicillin concentrations were measured serially over a 24-hour period. The absorption of amoxicillin was rapid and followed a 1st-order elimination. Mean peak serum concentrations occurred 30 minutes after the injection in foals at all ages and were 17.31 +/- 9.59 micrograms/ml when the foals were 3 days old, 23.28 +/- 9.86 micrograms/ml when the foals were 10 days old, and 21.35 +/- 6.39 micrograms/ml when th...
Galan JE, Timoney JF, Lengemann FW.Passive transfer of mucosal antibody to Streptococcus equi was studied in foals during the first 2 months of life. Immunoglobulin G (IgG) and IgA antibodies were found in sera and nasal secretions of foals shortly after colostrum intake. Titers were highest 2 days after birth; IgG predominated in sera, and IgA predominated in nasal washes. Intragastrically administered 99mTc-labeled IgA was transported from the bloodstream to the nasal mucosa of a newborn foal within a few hours of colostrum intake. Western blot analysis of the specificities of colostral and serum antibodies showed that select...
Hanson RR, Todhunter RJ.Abdominal wall hernia was detected in 4 pregnant mares. Antemortem diagnosis of the specific abdominal wall lesion was difficult. Ventral deviation of the abdomen, associated abdominal wall edema, and pain indicated rupture of the prepubic tendon. Three mares examined at necropsy did not have a rupture of the prepubic tendon but did have herniation of the abdominal wall. Abdominal pain was severe and was compounded by incarceration or entrapment of viscus.
Owen RA, Haywood S, Kelly DF.A four-year-old shire mare with haematuria, colic, terminal weight loss and an abdominal mass had a large unilateral renal adenocarcinoma. Clinical signs were monitored for 11 months. Increased serum copper concentrations were measured on two occasions. Hypercupraemia is discussed as a possible paraneoplastic change.
Bauer C, Bürger HJ.A paste formulation containing 14.3 per cent of oxibendazole and 44 per cent of trichlorfon was administered to 33 ponies and horses. The dose rate used was equivalent to 10 mg and 30 mg/kg bodyweight, of oxibendazole and trichlorfon respectively. After treatment 25 animals passed between one and 82 third stage larvae of Gasterophilus intestinalis in their faeces. Dosing with 0.2 mg ivermectin/kg bodyweight three weeks later resulted in six animals expelling between one and four bots. The efficacy of the oxibendazole-trichlorfon paste was on average 96.2 per cent. This drug combination given t...
Held JP, Wright B, Henton JE.A 20-year-old gelding with weight loss and generalized weakness that progressed gradually over a 3-month period was diagnosed as having pyelonephritis caused by Staphylococcus aureus infection. Abnormal laboratory findings included high values for BUN, creatinine, potassium, and calcium, and depletion of sodium. Determination of glomerular filtration rate and effective renal plasma flow indicated a severe decrease in renal filtration and perfusion.
Levine RA, Hart AH, Wardlaw SC.Using quantitative buffy coat analysis (QBCA), rapid and accurate measurements can be made of the erythrocyte PCV, total WBC count, and platelet count, and the leukocyte population can be differentiated into total granulocytes (including quantitation of eosinophils), and lymphocytes and monocytes. The QBCA is performed by placing a blood sample (50 to 111 microliters) into a high-precision-bore microhematocrit tube that contains a freely moving, closely fitting, cylindrical plastic float. After centrifugation for 5 minutes, the buffy coat components separate by density. The plastic cylinder fl...
Blue BJ, Pickett BW, Squires EL, McKinnon AO, Nett TM, Amann RP, Shiner KA.Gonadotrophin-releasing hormone (GnRH) was administered subcutaneously to reproductively normal stallions, either in a pulsatile manner (10 micrograms GnRH/2 h; n = 6) or as a continuous infusion (10 micrograms GnRH/2 h; n = 6), and in a pulsatile manner to 9 reproductively abnormal stallions, from February to July, 1988. Hormonal secretion patterns, testicular parameters and semen characteristics were monitored before and during treatment. In general, pulsatile GnRH caused a significant increase (P less than 0.05) in luteinizing hormone (LH) concentrations in the peripheral blood of normal st...
Peter AT, Colenbrander B, Gadella BM.The present study was designed to test the hypothesis that addition of anticaspase cocktails (inhibiting caspases and thus blocking apoptosis) to the extenders increases the post-thaw viability of equine spermatozoa. The addition of caspase inhibitors failed to improve the acrosome and plasma membrane integrity of spermatozoa, suggesting that in equine sperm cryopreservation protocols, the addition of these caspase inhibitors to cryopreservation medium may not be beneficial in protecting the sperm from the stress of cryopreservation.
Kraft W.Neurological examination in equine practice, physiological findings and pathological disturbances are described. Because of the sizes of the horse the neurological examination is more difficult than in small animals. The examination of cerebrospinal fluid is a worthful completion and is able to refer to the etiology of a certain disease. The technique of the puncture of cerebrospinal fluid is described.
Marquardt J, Heymer J, Heinz H, Deegen E, Adolf GR, Leibold W.Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is suf...
Vivrette SL, Irvine CH.Acyclic mare given oestradiol for 3 days to simulate the preovulatory plasma oestradiol surge showed a non-significant 37% decrease in plasma LH during treatment. When GnRH analogue injections were given with oestradiol on Days 1--3, oestradiol had no effect on each GnRH-induced LH increase, but LH increases were more prolonged following subsequent GnRH injections on Days 4--7 when oestradiol was no longer being given. A much greater prolongation of LH release occurred when the course of GnRH injections was commenced after oestradiol treatment ceased; the LH response was almost identical to th...
Rasbech NO, Koefoed-Johnsen HH, Holm G.On the basis of progesterone determination on plasma or blood after RIA and the kit method respectively and consecutive scanning performed on a total number of 31 mares the following features were demonstrated: The overall material shows that in 20 mares (64.5%) embryonic vesicles were demonstrated. Of these mares 16 have conceived after service in the 1st estrous cycle and 3 mares in the 2nd estrous cycle. 18 mares were scanned in the time interval 13th-26th day after the latest service, while 2 mares were scanned on day 46 and 41 respectively. A total of 14 scanning positive mares were exami...
Coignoul FL, Bertram TA, Cheville NF.Three pony mares and 4 pony foals were inoculated with a subtype 2 strain of equine herpesvirus 1. Foals had periods of fever 12 h and 2.5 days after inoculation and leukopenia, involving both neutrophils and lymphocytes, followed by leukocytosis. Mares had transient fever and leukopenia 24 hours after inoculation that were less severe than in foals. An increase in circulating virus-neutralizing antibody was seen in 2 of 3 inoculated mares, but not in foals. Attempts to isolate virus from blood were unsuccessful. These studies show that equine herpesvirus 1 subtype 2 is a mild pathogen for pon...
Długołęcka E, Tobolski D, Janowski T.Early embryonic death (EED) is one of the causes of infertility in the mare. We compared endometrial environment in 9 mares with EED and 13 mares in diestrus phase. Cotton swab (CS), cytobrush (CB) and uterine biopsy (B) samples were obtained for the cytological, bacteriological and histopathological examinations. In the first step we compared CS and CB methods to biopsy as a reference method, as B revealed the highest number of positive results in cytological and bacteriological examinations in both groups. In turn, we also compared cytological, bacteriological and histopathological findings ...
Booth AD, Hidalgo FL, Bellezzo F, Young JM, Bianco AW, Hughes LE, Maher M, Trumble TN, Ernst N.To describe outcomes of horses with temporohyoid osteoarthropathy (THO) treated with partial ceratohyoidectomy. 10 client-owned horses. Medical records from 2 institutions were examined for records of horses with THO treated with partial ceratohyoidectomy between 2010 and 2021. History, signalment, clinical signs, diagnostics, medications, and surgery-related details were recorded. Horses with a minimum of 6 months follow-up were recruited for neurologic and imaging examinations in the hospital or field where radiography of the basihyoid-ceratohyoid articulation were performed along with CT, w...
Romano MC, Francis KA, Janes JG, Poppenga RH, Filigenzi MS, Stefanovski D, Gaskill CL.Poisoning of nontarget species is a major concern with the use of anticoagulant rodenticides (ARs). At postmortem examination, differentiating toxicosis from incidental exposure is sometimes difficult. Clotting profiles cannot be performed on postmortem samples, and clinically significant serum, blood, and liver AR concentrations are not well-established in most species. We chose diphacinone for our study because, at the time, it was the publicly available AR most commonly detected in samples analyzed at the University of Kentucky Veterinary Diagnostic Laboratory. We determined an approximate ...
Dyer DC, Hsu WH, Lloyd WE.Twenty healthy ponies were given i.v. 1.1 mg/kg of xylazine from 2 manufacturers and the pharmacokinetic parameters calculated from the disposition curves. The disposition curves for the 2 commercial preparations were not different. Yohimbine, an antagonist of the pharmacologic effects produced by xylazine, did not alter the disposition of xylazine in the plasma. A single i.v. bolus of xylazine was completely described in 17 of 20 animals by the biexponential equation: Cp = 1.30e(-0.3955t) + 0.58e(-0.033t) where Cp represents the concentration of xylazine in the plasma at time t (min). The t1/...
Collier MA, Brighton CT, Rendano VT, Schryver HF, Kallfelz FA.Electrically induced osteogenesis exhibits a dose response curve and can induce bone formation in the absence of trauma and in nonunions. Electrically induced osteogenesis, using direct electric current (DC) in a third metacarpal diaphyseal osteotomy model, in conjunction with internal fixation and postoperative loading, was investigated. Twelve young adult ponies of mixed sex were divided into 2 treatment groups (A and B) of 3 stimulated and 3 controls each and evaluated, using a specifically designed procedure. Stimulated ponies in both groups were given 20 microA of DC via an implanted bone...
Bowling AT.Accuracy of assigning foal paternity to the second serving stallion for foals whose dams had been bred to two stallions within an interval of 1 to 45 days was investigated using breeding dates from 108 equine paternity cases solved by blood typing. One hundred two of the foals were sired by the second stallion but six foals (5.5%) were excluded as being by the second sires. Thus, breeding dates are not reliable as a sole source of information to assign equine paternity accurately.
Hoffmann KL, Wood AK, McCarthy PH, Griffiths KA, Evans DL, Gill RW.Investigations of the equine peripheral vascular system have been constrained by the lack of a non-invasive method of examining the arteries and veins of the limbs of the conscious horse. Precise correlations were established between the gross anatomical features of the peripheral vessels and their B-mode sonographic appearance in each thoracic limb of 35 horses. A sonographic imaging protocol was established. Additional Doppler sonographic recordings defined the arterial waveforms and demonstrated that blood flow to the foot could be evaluated in the lateral proper digital artery, distal to t...
Savage CJ, Jeffcott LB, Melsen F, Ostblom LC.Two hundred and five bone biopsies from the wing of ilium were taken from 52 growing and 70 older horses. The method was initially evaluated in 4 horses at post mortem and then performed in 26 horses under general anaesthesia. The technique was later developed for biopsying horses in the standing position under local anaesthesia (n = 70 adults; n = 22 foals). The core of the bone biopsy consisted of a central cancellous portion between two cortices. This type of sample allowed a complete histomorphometrical analysis. An integral part of the procedure was intravital bone labelling using fluoroc...
Weber JA, Woods GL, Freeman DA, Vanderwall DK.The objective of this experiment was to contrast the influence of the oviductal and uterine environments on development of Day-2 embryos. Embryos were transferred to oviducts or uteri of synchronous recipient mares, or were incubated in oviductal co-culture, in uterine co-culture or in defined culture medium. Significantly more (P < 0.02) embryos transferred to the oviduct versus the uterus survived until Day 11 after ovulation (5 7 vs 0 7 , respectively). Significantly more (P 0.1) in oviductal co-culture versus uterine co-culture (3 7 vs 6 7 , respectively), or in oviductal co-culture ve...