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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
The isolated perfused equine skin flap. Preparation and metabolic parameters. A model for the study of equine cutaneous physiology, pharmacology, and toxicology was developed. Four 4 x 12 cm and twenty-one 6 x 12 cm single-pedicle axial pattern skin flaps based on the caudal superficial epigastric artery, and eight 6 x 12 cm flaps based on the saphenous artery and medial saphenous vein, were raised and sutured in a tubed configuration. On day 2, each flap was removed, the artery was cannulated, and the flap was perfused with a modified Krebs-Ringer's albumin-based medium for at least 6 hours. Flap viability was assessed by glucose use, lactate production, and histologic...
Femoral head ostectomy in horses and cattle. Femoral head ostectomy was performed in six horses, three ponies, and four cattle for treatment of fractures of the femoral capital physis, coxofemoral luxation, fractured acetabulum, or severe degenerative joint disease. The procedures were performed via a cranial approach that did not involve osteotomy of the greater trochanter. A dorsal approach for femoral head ostectomy via osteotomy of the greater trochanter was evaluated in three healthy adult ponies. Three animals (2 ponies, 1 calf) were euthanatized within a month and one horse was euthanatized at year 2 due to postoperative complicat...
Measurement of cardiac dimensions with two-dimensional echocardiography in the living horse. Two-dimensional echocardiography (2DE) was performed on 22 unsedated Thoroughbred and part Thoroughbred horses weighing between 411 and 650 kg to establish normal reference values for 2DE measurements. Animals stood during examinations performed with a 3.5 MHz mechanical sector transducer using various transducer positions and tomographic planes. Right ventricular diameter (RVD), ventricular septal thickness (VSTh), aortic diameter (AoD), area of the chordal lumen of the left ventricle (CTA), left ventricular diameter (LVD) and left atrial diameter (LAD) were determined at ventricular end-dias...
The genetic basis of equine allergic diseases. 1. Chronic hypersensitivity bronchitis. The genetic influence on chronic hypersensitivity bronchitis (CB) was investigated in families at two studs and among half-siblings of three affected and three non-affected sires at several farms. The family members at the two studs were born and raised under the same conditions, whereas the half-siblings were kept individually under very different conditions and were exposed to various environmental factors. The diagnosis was based on long-term observations and multiple clinical examinations at each of the two studs. In the half-sibling group, the diagnosis was based on the individual history...
Immune-mediated thrombocytopenia in horses infected with equine infectious anemia virus. An adult horse infected with a virulent, cell culture-adapted strain of equine infectious anemia virus (EIAV) developed cyclical thrombocytopenia in which the nadir of platelet counts coincided with peak febrile responses. In order to investigate the mechanism of thrombocytopenia during acute febrile episodes, four adult horses were experimentally infected with the wild-type Wyoming strain of EIAV. Platelet counts decreased from baseline as rectal temperature increased. Serum reverse transcriptase activity increased above background levels in all horses, coincident with increase in rectal temp...
Bronchoalveolar lavage findings in horses with exercise intolerance. Significant differences were detected by bronchoalveolar lavage (BAL) between horses racing successfully and those showing exercise intolerance. Neutrophil percentage, haemosiderophage percentage and total bacterial numbers were significantly elevated in horses with exercise intolerance. BAL provided a more accurate indication of the incidence and extent of exercise induced pulmonary haemorrhage (EIPH) than visual inspection.
The prevalence of enteric pathogens in diarrhoeic thoroughbred foals in Britain and Ireland. A survey of 77 normal and 326 diarrhoeic foals in Britain and Ireland from 1987 to 1989 revealed a significantly higher prevalence of Group A rotaviruses and Aeromonas hydrophila in diarrhoeic foals. The prevalence of cryptosporidia, potentially pathogenic Escherichia coli, Yersinia enterocolitica and Clostridium perfringens was similar in normal or diarrhoeic foals. Rotaviruses had a similar prevalence in all age groups of scouring foals up to three months of age, with an overall prevalence of 37 per cent among diarrhoeic foals. The number of cases of diarrhoea varied considerably from year t...
Lymphosarcoma with urinary bladder infiltration in a horse. A 9-year-old Thoroughbred mare was examined because of pollakiuria, hematuria, and weight loss of 3 weeks' duration. Physical examination revealed a regular cardiac rhythm with occasional premature contractions, and a soft tissue mass in the pelvic canal palpable per rectum. Microscopic examination of urine sediment revealed numerous RBC and a large population of lymphocytes and lymphoblasts with characteristics of neoplasia. Similar cells were found in peritoneal fluid obtained by abdominocentesis. The horse was euthanatized without treatment. Necropsy revealed a soft tissue mass infiltrating...
Evaluation of epiglottic augmentation by use of polytetrafluoroethylene paste in horses. Epiglottic augmentation was evaluated in 7 horses, using 7 ml of polytetrafluoroethylene (polytef) paste injected submucosally on the ventral surface of the epiglottis. In 6 horses, an Arnold-Bruning intracordal injection syringe, specifically designed to inject polytef into paralyzed vocal folds in human beings, was used. At necropsy 60 days after surgery, group mean thickness measurement 20 mm from the epiglottic tip was 40% greater (P less than 0.01) and, at the epiglottic attachment of the aryepiglottic fold, was 29% greater (P less than 0.01) in the 6 polytef-augmented horses than in clin...
Desmitis of the accessory ligament of the deep digital flexor tendon: 27 cases (1986-1990). Desmitis of the accessory ligament of the deep digital flexor tendon (ALDDFT) was diagnosed in 27 horses between September 1986 and December 1990. The first observed clinical sign in four horses was localised swelling in the proximal metacarpus. Twenty horses became lame suddenly during a work period and most developed swelling within 24 h of exercise. The injury was confirmed by ultrasonographic examination. Ten of 13 horses with uncomplicated desmitis of the ALDDFT resumed full work, within three to nine months of the onset of clinical signs, without recurrence of clinical signs in the perio...
The influence of detomidine and epinephrine on heart rate, arterial blood pressure, and cardiac arrhythmia in horses. Detomidine (10 micrograms/kg and 20 micrograms/kg) was administered to seven horses with and without epinephrine infusion (0.1 microgram/kg/min) from 5 minutes before to 5 minutes after detomidine injection. One or more single supraventricular premature heartbeats were observed in three horses after detomidine administration. Epinephrine infusion did not modify the incidence of cardiac arrhythmias in detomidine-treated horses at the doses tested. Relatively high momentary peak systolic pressures were registered in some horses after detomidine administration during epinephrine infusion. The hig...
Pharmacologic treatment of priapism in two horses. Benztropine mesylate was used successfully to treat priapism that developed during anesthesia in 2 horses. After IV injection, there was a rapid resolution of signs in both horses, and no side effects were observed. The choice of an effective method to treat priapism is challenging because precise causes in most patients have not been well-defined. Benztropine mesylate is a synthetic compound resulting from the combination of the active portions of atropine and diphenhydramine, and is believed effective because of its central acetyl-choline-antagonizing properties.
Effect of storage on measurement of ionized calcium and acid-base variables in equine, bovine, ovine, and canine venous blood. The stability of blood ionized calcium (Ca2+) and acid-base variables in equine, bovine, ovine, and canine venous blood samples (n = 15, in each group) stored at 4 C for 3, 6, 9, 24, or 48 hours was studied. Variables included blood Ca2+ and standard ionized calcium (Ca2+ corrected to pH 7.4) concentrations, pH, blood carbon dioxide and oxygen tensions, base excess, bicarbonate concentration, and total carbon dioxide content. Results indicate that storage of blood samples at 4 C for up to 48 hours, despite appreciable acid-base changes, is associated with less than 1.5% change in equine, bovin...
Traumatic injuries involving tendons of the distal limbs in horses: a retrospective study of 55 cases. Fifty-five horses were presented to Colorado State University Veterinary Teaching Hospital between 1st of January 1980 and 31st of December 1989 for treatment of distal limb lacerations involving flexor tendons (n = 35) or extensor tendons (n = 20). Of the 35 flexor tendon lacerations, 11 horses were killed without treatment and 24 horses were treated. Twenty-two horses were included in determining outcome. Four (18 per cent) returned to their original level of use, nine (41 per cent) returned to limited riding, seven (32 per cent) returned to breeding or pasture soundness and two (9 per cent)...
Mononuclear cell infiltration of the equine endometrium: immunohistochemical studies. Endometrial sections from mares with varying degrees of mononuclear cell infiltration were examined for immunoglobulin (Ig)A-, IgM-, IgG(T)- and IgG(Fc)-containing cells, luminal and glandular epithelial cell Ig-staining and free interstitial Ig-staining, using a peroxidase anti-peroxidase technique. Mares with mild to moderate (Group 2) and mares with severe diffuse mononuclear cell infiltration, superimposed by acute endometritis (Group 3), had significantly higher numbers of Ig-containing cells than genitally-normal mares (Group 1). The differences between Groups 1 and 3 were significant fo...
Time of embryo transport through the mare oviduct. The objectives of this study were 1) to determine the time of embryo transport through the mare oviduct, 2) to determine whether equine embryos increase in diameter prior to the time of oviductal transport, and 3) to assess the stage of equine embryonic development at the time of oviductal transport. The time of oviductal transport (interval from ovulation to uterine entry) was estimated by collecting embryos from the mare oviduct or uterus at 2-hour intervals from 120 to 168 h postovulation. The time of oviductal transport was 130 to 142 h, since 9 9 embryos were located in the oviduct from 1...
Factors associated with failure of passive transfer of colostral antibodies in Standardbred foals. The records of 361 Standardbred mares and their 1986 or 1987 foals were evaluated to identify factors associated with failure of passive transfer (FPT) of colostral antibodies in equine neonates. Sixty-five foals (18%) were classified as FPT based on a serum immunoglobulin concentration of less than 400 mg/dl at 24 to 36 hours of age, determined by the glutaraldehyde coagulation test. The potential association of mare- and foal-related factors with FPT were assessed by reviewing a series of multiple logistic regression models. The season in which the mare foaled and foal exam score, a subjecti...
Risk factors associated with injuries in thoroughbred horses. A case-control study was conducted on Thoroughbred horses to identify factors associated with the risk of breakdown on racetracks. A total of 310 cases (breakdowns) were identified from the Horse Identification Department records kept by the chief examining veterinarian of New York Racing Association. For each case, two control horses were selected randomly from the Daily Racing Form Inc. records. Multiple logistic regression analysis was used to identify and quantify the risk of factors associated with breakdown, while simultaneously controlling for the effect of other putative factors. Facto...
Measurement of oxytocin concentrations in plasma and ovarian extracts during the oestrous cycle of mares. Jugular venous blood samples were collected throughout a complete oestrous cycle from 9 mares for measurement of progesterone and oxytocin by radioimmunoassay. Mean oxytocin concentrations remained at approximately 1 pg/ml throughout, with no evidence of cyclic variation in the release pattern. Extracts of corpus luteum and follicles obtained from a further 33 mares at different stages of the cycle all contained oxytocin concentrations of less than 10 pg/g wet weight of tissue. We conclude that the ovaries are not a source of circulating oxytocin during the oestrous cycle in this species. The ...
Stability of equine lysozyme. I. Thermal unfolding behaviour. The thermal denaturation of Ca(2+)- and apo-forms of equine lysozyme was followed by using far and near UV circular dichroism and intrinsic fluorescence methods. The difference found between the temperature dependence of the ellipticity at 222 nm and 287 nm, which show two stages in the thermal transition, and those at 228 nm and 294 nm, which indicate only one stage over a wide range of temperatures reflects that different subdivisions of the protein molecule are characterized by a different stability, cooperativity and pathway of denaturation. The first transition, reflected in the increase ...
Electromagnetic stimulation of bone repair: a histomorphometric study. The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of ...
Histopathological and ultrastructural changes in simulated large colonic torsion and reperfusion in ponies. This investigation examines the histological and ultrastructural lesions of the colonic mucosa during terminal experimental infarction and subsequent reperfusion. Four ponies were anaesthetised and subjected to surgical torsion of the colon. Biopsies were collected at hourly intervals for 3 h, at which point the torsions were corrected. Circulation was re-established for 2 h and the bowel was re-biopsied at hourly intervals. The ponies were killed while under anaesthesia. During the 3 h experimental infarction, the bowel became macroscopically thickened and dark purple. Histologically, the muc...
Quantifying the occurrence of early embryonic mortality on three equine breeding farms. This prospective field study was designed to describe the incidence of early embryonic mortality (EEM) and factors associated with the cause of EEM on three equine breeding farms in Ontario during the 1989 breeding season. Early embryonic mortality was defined as the loss of a single embryo during the first 40 days of pregnancy (day 0 = day of ovulation or last breeding). Pregnancy diagnoses and subsequent embryonic losses were observed by serial trans-rectal ultrasonography between days 12-20 (PD1) and 21-30 (PD2), and by trans-rectal ultrasonography or palpation per rectum between days 31-40...
Therapeutic management of ocular squamous cell carcinoma in the horse: 43 cases (1979-1989). The records of 50 horses with ocular squamous cell carcinoma (OSCC) presented to the University of Florida Veterinary Medical Teaching Hospital over an 11 year period were reviewed to determine the influence of therapy on the outcome of the case. Follow-up information was obtained for 43 of the 50 cases. The disease was more prevalent in the light horse breeds; however, the draft breeds also were at risk. There was no sex predisposition and the average age was 11.8 years. Tumour recurrence was significant when surgery alone was performed. The eyelid and nictitating membrane were the primary si...
Plasma histamine levels in laminitic horses and in horses treated with a corticosteroid. In seven sound horses histamine plasma levels were evaluated by means of a radioenzymatic method using the enzyme histamine-N-methyltransferase (mean = 4.46 nmol/l, SD = 1.55 nmol/l). Histamine levels of laminitic horses were significantly higher (n = 11; mean = 12.46 nmol/l, SD = 3.24 nmol/l). In three sound horses plasma histamine levels were determined over a two week period following a double administration of 10 mg dexamethasone-21-isonicotinate/100 kg body weight. Histamine levels remained within the range of sound control horses.
Pharmacokinetics of caffeine and its metabolites in horses after intravenous, intramuscular or oral administration. The pharmacokinetics of caffeine (CAF) and its metabolites, dimethylxanthines, were examined in horses administered 2.5 mg/kg of CAF intravenously (i.v.), intramusculary (i.m.), or orally (p.o.). The plasma samples were extracted by Extrelut and the concentrations of CAF and metabolites were determined by high performance liquid chromatography (HPLC) with a short column. The pharmacokinetics of CAF after bolus i.v. injection were described by the assumption of a two-compartment model, and those of CAF after i.m. or p.o. administration were done by the assumption of a one-compartment model. The...
Incorporation of fresh and cryopreserved bone in osteochondral autografts in the horse. The structural integrity of subchondral bone in fresh and frozen osteochondral autografts was investigated at month 3 in 10 horses. Two osteochondral autografts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. Grafts were frozen in 7.5% DMSO. After 14 days, the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifles. A fresh graft from the right hock was implanted in each left stifle. To control for the effects of surgery, a fresh graft was transferred from the right stifle to the le...
Rostral mandibulectomy in five horses. Rostral mandibulectomy with primary gingival closure was performed in 5 horses with rapidly growing or bleeding mandibular tumors. The technique involved preservation of the most caudal portion of the mandibular symphysis to maintain stability. There were no surgical complications or recurrences, and the cosmetic and functional results were good. The histopathologic diagnosis of all the tumors was ossifying fibroma. Rostral mandibulectomy affords a simple and effective technique of treating tumors of the rostral portion of the mandible in horses.
Anomalies of centriolar derivatives manifest in spermatic flagella and respiratory cilia of the stallion. Anomalies of centriolar derivatives were identified in ejaculates and testicular and tracheal biopsies of a sterile stallion, using light, scanning, and transmission electron microscopy. LM revealed that over half the sperm population had only a vestigial or no tail, while the rest had tails of variable length and shape. The vestigial tail was represented by its anlage, which was implanted on the nucleus and differentiated up to capitulum and collum stage. The stunted tail had an axoneme and its derivatives, but was short in all tail segments. Regardless of the tail length or shape, virtually ...
Thermodilution estimation of cardiac output at high flows in anesthetized horses. The purpose of this study was to compare the thermodilution technique for estimation of cardiac output with the indocyanine green dye dilution technique at flows between 10 and 39 L/min in halothane-anesthetized horses. The estimation of area of dye dilution cardiac output curves was made by using the fore-'n-aft (FA) triangle method. This shorthand technique was compared with logarithmic exponential extrapolation and summation (extrapolated area), using 64 cardiac output curves. Then, 256 simultaneous thermodilution measurements were compared with dye dilution measurements calculated by use o...
