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.
Pedersoli WM, Fazeli MH, Haddad NS, Ravis WR, Carson RL.Endometrial tissue and blood serum gentamicin (GT) concentrations were determined in 6 ovariectomized pony mares given intrauterine infusions (50 ml of a 5% commercial aqueous solution of GT) each day for 5 consecutive days. The mares were subjected to the following 3 treatments: (1) GT infusion only (trial A, control); (2) progesterone plus GT (trial B, P + G); and (3) estradiol plus GT (trial C, E + G). Endometrial tissue concentrations of GT (micrograms/g) at 24 and 120 hours were significantly higher (P less than 0.05) in trials B (65.54 +/- 15.57 and 100.33 +/- 19.27) and C (73.33 +/- 22....
Brockschmidt LD, Loch WE, Sikes JD.An experiment was conducted to test the effect of repeated transcervical (non-surgical) uterine flushing and a prostaglandin analogue (PG) on the estrous cycle of pony mares. Uteri in group A were trancervically flushed for embryos 7 to 9 days post ovulation. In addition, group B mares were given 5 ml of PG by intramuscular injection on the day of flushing. Group C served as controls and were not flushed or given PG but were allowed to cycle normally. All mares (except controls) were bred A.I. every other day during estrus. There was no effect on embryo recovery rate from repeated flushing or ...
Chan CW, Collins EA.An angiosarcoma involving the right frontal and maxillary sinuses in a nine-year-old Thoroughbred mare was studied post mortem by light and electron microscopy. Important diagnostic features included malignant endothelial cells lining ill-defined vascular spaces, supported by other vasoformative elements. Rhabdomyoblasts were also found. The tumour is apparently rarely seen in the nasal passages of the horse.
Miller PJ, Holmes JR.Observations on seven cases of mitral insufficiency are described. Three of the horses had recent histories of cardiac failure and formed a separate group in which there were marked haemodynamic changes which varied in relation to heart rate but were associated with pulmonary hypertension, elevated right ventricular pressure and low peak left ventricular pressure. In the other four horses the heart appeared to be compensating at rest but to be unable to cope with severe exertion. On auscultation, a widespread pansystolic murmur and a prominent third heart sound were characteristic of the left ...
Duncan ID, Brook D.Four two-year-old Thoroughbreds suffered an acute gastrointestinal illness shortly after dosing with mineral oil which was thought to have been contaminated with an organophosphate compound. Three weeks later all four were noted to be dyspnoeic and endoscopic examination showed that they had developed bilateral laryngeal paralysis. Two of the horses died during severe bouts of dyspnoea six and eight months later and the third was killed shortly thereafter. Examination of the left and right recurrent laryngeal nerves from these horses showed a severe loss of myelinated fibres distally, especial...
Dunsmore JD.An attempt was made to control or eliminate Strongylus vulgaris from a closed group of three horses at pasture near Perth, Western Australia, by dosing with ivermectin on four occasions during the time of year when it was believed that environmental conditions would eliminate all the non-parasitic stages of that species. At necropsy, five months after the last dose of anthelmintic and after continually grazing the same pastures, no S vulgaris or arterial lesions were found in those horses and S edentatus, Draschia megastoma and Habronema species were also almost completely eliminated.
Goulden BE, Anderson LJ, Cahill JI.An endoscopic survey was performed to assess arytenoid cartilage movement during quiet respiration in 48 Clydesdale horses. Physical characteristics which could influence the length of the recurrent laryngeal nerves were also recorded from these horses and the relationship of these characteristics to the presence of abnormal left arytenoid cartilage movements was assessed statistically. Some degree of abnormal arytenoid movement was observed in 50% of the animals over one year of age. No significant correlation between sex, age, estimated weight, height, or neck length could be found although ...
Dunsmore JD, Jue Sue LP.A survey was conducted on the prevalence of the major gastrointestinal parasites in 140 horses necropsied in Perth, Western Australia, during 1979 to 1982. Adult Strongylus vulgaris were found in 22.5 per cent of horses and verminous arteritis in 62.9 per cent. The peak worm prevalence was in November to January (summer). S edentatus had a similar prevalence and seasonality but S equinus was not found in this survey. Draschia megastoma and Habronema muscae were found in 66.2 per cent and 35.3 per cent of horses respectively. Infection is probably acquired in summer when 8 per cent of the Musca...
Issel CJ, Adams WV, Foil LD.Progeny of a band of horses, positive by the agar-gel immunodiffusion (AGID) test for equine infectious anemia (EIA) antibody, were observed through their weaning over a 4-year period. Sentinels (AGID test-negative) were allowed to mingle with EIA-infected mares and their foals in pasture situations in an area with high populations of potential vectors. Of 27 adult sentinels, 8 (30%) seroconverted in annual rates ranging from 0% to 75%. In contrast, only 2 of 31 (6%) foals weaned became infected. Difference in infection rates between adult sentinels and foals was significant (chi 2, P less tha...
Leaper DJ, Foster ME, Brennan SS, Davies PW.Magnetic fields have been considered for treating many ailments over man's history. There have been many anecdotal unsupported claims for successful treatment of soft tissue injury although reports have been more substantive in the orthopaedic field. The widespread clinical and veterinary use of a light self-adhesive magnetic foil in Europe prompted this trial of experimental wound healing. One hundred and sixty Sprague-Dawley rats had a linear 2.5 cm incision or a circular 1 cm skin defect made over the mid-dorsal spine. Equal numbers were randomised to receive either a magnetic foil or a dum...
Clemmons RM, Lee MR, Bliss EL, Asbury AC, Cook D, Brown V.Superoxide dismutase (SOD), a free radical scavenger with anti-inflammatory activity, was administered IM to horses. Ex vivo platelet aggregation in response to arachidonic acid was monitored to determine whether exogenous SOD altered equine platelet prostaglandin metabolism. Preparations of platelet-rich plasma obtained before SOD administration were incubated with different concentrations of SOD and were aggregated with arachidonic acid. Superoxide dismutase did not exert a demonstrable effect, either ex vivo or in vitro. Aspirin abolished arachidonic acid-induced platelet aggregation in vit...
Widders PR, Stokes CR, David JS, Bourne FJ.The effect of cycle stage on immunoglobulin and albumin levels in serum, follicular fluid, oviductal, uterine and vaginal secretions was measured. There was no variation in serum immunoglobulin levels during the oestrous cycle, although IgM levels were elevated in cyclic mares compared to non-cyclic (immature and anoestrous) animals. Similarly, there was no cyclical variation in follicular or oviductal protein concentrations. In the uterus, IgG and IgA levels relative to total protein were higher in oestrogenic than in progestagenic secretions, while the trend in relative IgM concentrations wa...
Gronwall R, Price G.To determine the rate of urine flow and thus urinary excretion in the horse from untimed urine samples alone, the flow rate, creatinine concentration, osmolarity, and refractive index of 228 quantitatively collected urine samples were determined in 53 experiments on 12 healthy Thoroughbred mares. Forty samples were collected after water-induced diuresis; 11 samples were collected after furosemide-induced diuresis. Flow rates, which ranged from 1.2 to 84.5 ml/min, could be predicted from the urinary creatinine concentration. Correlation of urinary flow with urinary creatinine concentration acco...
Davies JV, Gerring EL.Small intestinal ischaemia is a cause of pain in man and horses. Occlusion of the vascular supply to Thiry loops in experimental ponies caused severe discomfort and loss of motility within a few minutes but these effects could not be reproduced by a similar procedure in intact gut preparations. However, embolisation of the mural vascular network produced ischaemia of the small intestine of anaesthetised ponies which led to a cessation of motility in the affected segments, though unaffected segments became hypermotile with a characteristic motility pattern. These results suggest the need for re...
Widders PR, Stokes CR, Newby TJ, Bourne FJ.This study identifies nonimmune binding of equine immunoglobulin by the causative organism of contagious equine metritis. Immunoglobulin binding to the bacterium was strongest for immunoglobulin G (IgG) and less for IgM; IgA was not bound. Binding of equine IgG was inhibited by human IgG, but not by IgG of domestic animals. Immunoglobulin binding by the bacterium appeared to be directed towards an epitope in the hinge region of the immunoglobulin molecule.
Herd RP, Willardson KL, Gabel AA.An investigation of the spring rise in strongyle egg output of grazing horses on two commercial horse farms in northern USA in 1981 and 1982 revealed two distinct spring and summer rises in faecal egg counts, with peaks in May and August/September. There was a marked rise in the concentration of infective larvae on pasture two to four weeks after the peaks in egg output, so that grazing horses were at serious risk from June onwards and pasture larval counts on one farm did not fall to low levels until June of the following year. The spring and summer rises in faecal egg counts appeared to be s...
Persson SG, Ullberg LE.Blood volume and parameters of body size were studied in 45 Standardbred foals during their first 400 days of life. Bodily dimensions, including body weight (bwt), depth of chest, girth and length (distance from point of shoulder to caudal aspect of croup), increased curvilinearly with age. There was a much faster growth rate noted for the first 100 days of life. Bwt could be predicted from girth and length much more precisely than from age alone. The total blood volume increased proportionately with age and, consequently, the plasma and red cell volumes as functions of bwt were high at birth ...
Koterba AM, Wozniak JA, Kosch PC.This study investigated the developmental changes in the mechanical properties of the respiratory system in growing horses. Pulmonary mechanics and lung volumes were serially measured in anesthetized foals during the first year of life. Quasi-static pressure-volume curves were generated, and functional residual capacity (FRC) was measured using a closed nitrogen equilibration technique. At birth, chest wall compliance normalized to body weight was substantially less than that reported in other less precocious newborn species, while lung compliance normalized to body weight was similar to value...
Webbon PM.A series of experimental tendon biopsies is described. Three biopsies were taken from the lateral digital extensor tendon (LDET) and three from the superficial flexor tendon (SFT). The LDET biopsies resulted in little discomfort whereas the SFT biopsies led to temporary lameness. The tendons were examined histologically up to 99 days after the biopsies were removed. In all of the tendons the defect filled with granulation tissue which subsequently became organised as a longitudinally orientated collagenous scar tissue. In this small series of biopsies the histological effects of the biopsy per...
Ramzan PHL, Wylie CE.Arthroscopy is considered the treatment of choice for dorsal osteochondral chip fractures of the metacarpo/metatarsophalangeal (MCP/MTP) joints in the racehorse; however, there is no published research on non-surgical management of this injury. Objective: To compare clinical features, intra-articular medication use and return to racing in Thoroughbred racehorses with non-surgically (non-SX) or surgically (SX) managed MCP/MTP dorsal chip fracture. Methods: Retrospective observational study conducted between 2006 and 2014. Methods: Radiographs of Thoroughbred racehorses were reviewed to identify...
Collier MA, Rendano VT, Kallfelz FA.A delayed union metacarpal stress fracture was repaired in a horse, using lag-screw fixation in conjunction with dc electrical stimulation. Twelve weeks after surgery, radiographic and scintigraphic evaluations revealed that the fracture line was not discernible and that there was a decrease in radiopharmaceutic uptake, as compared with that in previous bone imaging studies. In this horse, DC stimulation of a delayed union stress fracture in a bone resulted in a healing pattern similar to that in human beings with delayed union fractures when treated with electrical stimulation.
Maxwell JA.A 9-year-old mare exhibiting signs of colic late in pregnancy was presented. Uterine torsion was diagnosed and corrected by caesarean section. A live foal was delivered and the mare survived the surgical interference.
Hoeberg E, Haga HA, Lervik A.To investigate whether morphine causes a change in mean arterial blood pressure (MAP) heart rate (HR) and oxygen extraction (OE) rate in healthy horses anesthetized with isoflurane and a dexmedetomidine infusion. Unassigned: The study design was prospective clinical, randomized, blinded two groups including 33 horses. All horses were sedated with romifidine IV, and anesthesia was induced with midazolam IV and ketamine IV and maintained with isoflurane in oxygen and medical air and a dexmedetomidine infusion. As a baseline venous and arterial blood, HR and MAP were sampled. Thereafter either mo...
Sudan V, Sharma RL, Gupta SR, Borah MK.The occurrence of Eimeria leukarti infection in equine is being sporadically documented despite its cosmopolitan prevalence. A Marwari mare, aged 3 years and 6 months and owned by a socio-economically weaker class of labourer of royal families, was suffering from non specific enteric disorders. Detailed systemic clinical examination of mare confirmed subclinical enteric infection with E. leukarti and piroplasms of Babesia (Theileria) equi in the circulating erythrocytes. She was therapeutically managed with synchronous administration of specific and supportive therapy with success. Non speci...
Fielding CL, Deane EL, Major DS, Mayer JR, Love JC, Peralez MS, Magdesian KG.The addition of calcium to resuscitation fluids is a common practice in horses, but studies evaluating the effects of calcium supplementation are limited. In healthy horses, decreases in heart rate and changes in serum electrolyte concentrations have been reported. Objective: Calcium gluconate administration at a rate of 0.4 mg/kg/min to eliminated endurance horses with metabolic problems will affect heart rate, gastrointestinal sounds, and serum electrolyte concentrations. Methods: Endurance horses eliminated from the Tevis Cup 100-mile (160 km) endurance ride for metabolic problems and req...
Curtiss AL, Parente EJ.To report an epiglottopexy technique for the treatment of epiglottic retroversion (ER) in 2 horses. Methods: Case report. Methods: A 2-year-old thoroughbred gelding and a 6-year-old standardbred gelding, both with ER. Methods: Epiglottic retroversion was diagnosed via exercising endoscopic examination in both horses. Epiglottopexy technique was performed in both cases. Results: Both horses returned to previous racing class within 1 year after surgery. Repeat exercising endoscopy of 1 horse 6 months postoperatively revealed resolution of the ER. Conclusions: Epiglottopexy should be consider...
Allen AL, Scott WM, Cook SJ, Fretz PB, Doige CE.Studies were conducted to determine the effects of delaying the separation of serum from the clot and of long-term storage of serum samples on the measurement of thyroid hormones in blood from horses using a fluorescence polarization immunoassay. The measured concentrations of T3 and T4 were not affected by leaving serum on the clot for as long as 24 hours at room temperatures. Storage of serum for 19 to 22 months at -20 degrees C resulted in significant increases of measured T4, but not T3. These studies support previous work demonstrating that thyroid hormones are resistant to degradation, i...
Hall MC, Fenelon AR, McDonald RD, Steel JD.Different techniques for monitoring cardiac responses to exercise in the horse have been described and evaluated. For experimental work of this type in a normal training and racing environment, the electrode system described when used with a portable magnetic tape recording system provided the best means of obtaining useful and reproducible data.
Roe HA, Biedrzycki AH, Davenport PW, Freeman DE, Porter EG, McCarrel TM.To develop 3D models of larynges to compare arytenoid abduction measurements between specimens and models, and to investigate the anatomic feasibility of placing an implant across the cricoarytenoid joint (CAJ) with or without arthrotomy. Methods: Cadaveric equine larynges (n = 9). Methods: Equine larynges underwent sequential CT scans in a neutral position and with 2 arytenoid treatments: bilateral arytenoid abduction (ABD) and bilateral arytenoid abduction after left cricoarytenoid joint arthrotomy (ARTH). Soft tissue, cartilage, and luminal volume 3-dimensional models were generated. Rima g...
Palm F, Walter I, Nowotny N, Budik S, Helmreich M, Aurich C.In most mammalian species, progestins have a major function in maintaining pregnancy. In humans, the physiologic initiation of parturition bears similarities with inflammatory processes and anti-inflammatory effects of progestins have been suggested to postpone birth until term. To examine if comparable effects exist in the horse, mares were treated with the synthetic progestin altrenogest from day 280 of gestation until parturition (N = 5) or were left untreated as controls (N = 7). Tissue from the amnion (AMN), allantochorion (AC), and endometrium (EM) was collected at foaling and mRNA expre...
Ford EJ, Evans J.1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C]glucose and [2-3H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting the total entry rate fell from 1.44 +/- 0.11 (n4) to 1.19 +/- 0.12 mg/min per kg body-weight (P less than 0.01) and irreversible loss fell from 1.36 +/- 0.10 (n4) to 1.05 +/- 0.10 mg/min per kg body-weight (P...
Engelking LR, Lofstedt J, Blyden GT, Greenblatt DJ.The following studies were designed to evaluate plasma elimination kinetics of intravenously administered antipyrine, acetaminophen and lidocaine among 9 healthy adult horses and 9 healthy drug-free humans (3 each per drug group), in order to compare potential species differences in drug-metabolizing ability. Acetaminophen is largely biotransformed in humans by hepatic glucuronide and sulfate conjugation, whereas both antipyrine and lidocaine are oxidized by hepatic microsomal mixed-function oxidases. Thus, plasma clearances of these drugs are thought to reflect differences in hepatic oxidativ...
