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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.
Comparative study of the oxyhaemoglobin dissociation curve of four mammals: man, dog, horse and cattle. 1. The entire oxygen dissociation curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO2 40 mmHg and T 37 degrees C, varies between 23.8 (+/- 0.8) mmHg for the horse, 25.0 (+/- 1.4) mmHg for cattle, 26.6 (+/- 1.2) for man and 28.8 (+/- 2.6) mmHg for the dog. 3. The higher dispersion of the dog's P 50 is due to difference between breeds;...
Lack of residual lung damage in horses in which Rhodococcus equi-induced pneumonia had been diagnosed. The effect of prior Rhodococcus equi-induced pneumonia on pulmonary health was investigated in 5 horses (< 24 months old) using endoscopy, radiography, hematologic and bronchoalveolar lavage analyses, and pulmonary function testing. Rhodococcus equi-induced pneumonia had been diagnosed in principal horses when they were foals. Diagnosis was based on positive results of transtracheal aspiration and thoracic radiography at the time of initial clinical examination. Results of reevaluation of the respiratory system of these horses (R+) were compared with those of 5 age-matched healthy horses (R...
[Concentration of species alien (bovine) IgG in the blood serum of foals after the intake of non-species specific colostrum preparation]. Sixteen vital foals with free access to maternal colostrum received a additional non-species-specific commercial colostrum additive within the first 18 hours of their life. The additive had been prepared from bovine colostrum. At birth no bovine IgG was detectable. The concentration of bovine IgG reached its maximum 18 hours post natum with XG = 74.6 mg/dl. 96 hours after birth IgG levels had dropped to XG = 20.9 mg/dl. The correlation of bovine IgG with GGT-activity was highly significant. Formation of antibodies against bovine IgG could not be demonstrated. It is not possible to increase igG...
Feeding status affects glucose metabolism in exercising horses. Four standardbred horses were used in a Latin square design experiment to evaluate the effects of feeding status on metabolic response to exercise. Horses were deprived of food overnight and then fed 0 (control condition), 1, 2 or 3 kg of corn grain approximately 2.5-3 h before exercise. The exercise test consisted of a warm-up phase (heart rate mean = 144 beats/min) followed by 800 m of walking and then a high intensity work bout for 1600 m (heart rate mean = 206 beats/min). All tests were conducted on a high speed equine treadmill on which the horses had been previously conditioned. During e...
Effects of cocaine on incremental treadmill exercise in horses. Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to ...
Evaluation of occlusive dressings for management of full-thickness excisional wounds on the distal portion of the limbs of horses. Two 2.5-cm2 full-thickness skin wounds were created surgically over the lateral aspect of the cannon bone of each limb of 6 horses (n = 48 wounds). Dressings evaluated were a nonadherent gauze pad (group 1); a synthetic semiocclusive dressing, (group 2); equine amnion (group 3); and a synthetic fully occlusive dressing (group 4). Wounds were assessed subjectively at each dressing change, and total wound area, area of granulation tissue, and area of epithelium in each wound were determined by computerized digital analysis of photographs of the wounds. Complete healing time (wound covered by epi...
Rheological characteristics of horse blood: significance during exercise. When horses maximally exercise, splenic contraction and fluid movement out of the vascular compartment greatly increase the hematocrit (up to 0.70). We studied the in vitro rheological characteristics of blood from Thoroughbreds and Quarter Horses to determine the interaction of hematocrit and shear rate on apparent viscosity. We also compared the rheological characteristics of the blood before and after horses received furosemide, a drug commonly used to prevent exercise-induced pulmonary hemorrhage. Although the apparent viscosity of blood with a high hematocrit was high at low shear rates, ...
Preventive administration of bovine colostral immunoglobulins for foal diarrhea with rotavirus. Foal diarrhea due to serotype 3 rotavirus broke out on a foal-raising farm in the years 1987 and 1989. In 1989, all of the foals, regardless of whether or not they suffered from diarrhea, received bovine colostral immunoglobulin (Ig) powder orally for 3 to 5 days during the epidemic. The morbidity of the diarrhea was lower than that observed in 1987, when the Ig powder was not administered to foals. These data suggested that the administration of Ig powder might partially prevent foal diarrhea with rotavirus infection.
Identification of the activation domain of equine infectious anemia virus rev. Several members of the lentivirus family of complex retroviruses have been shown to encode proteins that are functionally equivalent to the Rev posttranscriptional regulatory protein of human immunodeficiency virus type 1 (HIV-1). Furthermore, the domain organization of HIV-1 Rev, featuring a highly basic N-terminal RNA binding domain and a leucin-rich C-terminal effector domain, has also been shown to be highly conserved among Rev proteins derived from not only the primate but also the ovine and caprine lentiviruses. Although it has therefore appeared highly probable that the lentivirus equin...
A comparison of the actions of platelet activating factor (PAF) antagonists WEB 2170 and WEB 2086 in the horse. The effects of the selective platelet activating factor (PAF) receptor antagonist WEB 2170 on PAF-induced responses in equine cells and tissues have been examined and compared with those of WEB 2086. In initial experiments WEB 2170 was shown to inhibit in vitro platelet aggregation in a dose-dependent, competitive reversible manner (pA2 = 7.21). Co-administration of the antagonists with either PAF or histamine also inhibited PAF, but not histamine, induced wheal formation and PAF-induced neutrophil accumulation in vivo in equine skin. Intravenous (i.v.) administration of both drugs at a dose o...
Effects of the 21-aminosteroid U-74389G on ischemia and reperfusion injury of the ascending colon in horses. Sixteen horses were allotted at random to 3 groups: vehicle only; low dosage (vehicle and 3 mg of U-74389G/kg of body weight); high dosage (vehicle and 10 mg of U-74389G/kg). These solutions were given prior to reperfusion. The ascending colon was subjected to 2 hours of ischemia followed by 2 hours of reperfusion. Before, during, and after ischemia, full-thickness colonic tissue biopsy specimens were obtained for measurement of malondealdehyde (MDA) concentration and myeloperoxidase activity and for morphologic evaluation. Although increases were not significant, MDA concentration and myelope...
Prejunctional alpha 2-adrenoceptors inhibit acetylcholine release from cholinergic nerves in equine airways. To determine the presence and function of alpha 2-adrenoceptors on cholinergic nerves innervating horse airway smooth muscle, the effects of some alpha 2-adrenoceptor agents on contractions of and acetylcholine (ACh) release from equine airway smooth muscle preparations were studied. Muscle contractions were elicited by either electrical field stimulation (EFS) or exogenous ACh. ACh release was induced by EFS and measured by high-pressure liquid chromatography and electrochemical detection. The alpha 2-adrenoceptor agonists clonidine (10(-7) to 10(-5) M) and UK-14,304 (10(-8) to 10(-6) M) conc...
A rapid diagnostic assay for eastern equine encephalomyelitis viral RNA. Eastern equine encephalomyelitis virus (EEEV) has been a low-frequency, but serious human and veterinary health problem. Increased frequency of this mosquito-borne virus is anticipated as wetlands are maintained and re-established. Control of EEEV has depended on mosquito abatement in response to increasing frequency of EEEV in the environment. A coupled reverse transcription/polymerase chain reaction assay was designed to rapidly, sensitively, and specifically detect EEEV RNA. The assay successfully detected the viral RNA in a single-blind study of a set of field samples composed of either po...
[Narcolepsy in horses]. Narcolepsy is an incurable non-progressive disease of the central nervous system. In humans, narcolepsy causes excessive drowsiness during the day (sometimes a sleep-attack occurs), cataplexy (sudden loss of muscle tone), hallucinations, and sleep paralysis. In the horse and other mammals cataplexy is the most frequently observed symptom. Excessive drowsiness can occur but is harder to observe. Cataplexy is caused by a fragmentation of the REM sleep. The etiology of narcolepsy is still subject to debate, partly because normal sleeping patterns are poorly understood. In humans and certain breed...
Sedatives, tranquilizers, and stimulants. Drugs of relevance to equine practice that modify the central nervous system (CNS) can be broadly classified as depressants or stimulants. The pharmacologic mechanisms of action, uses, and side effects of selected CNS depressant and stimulant drugs in horses are reviewed. Knowledge of the way these CNS-modifying drugs may affect performance is limited.
Regulatory aspects of drug use in performance horses. The control of drug use in performance horses and the policing of rules and regulations to prevent unauthorized drug use are important tasks for agencies overseeing equestrian events. This article describes the roles of the American Horse Shows Association, the Federation Equestre Internationale, and the Association of Racing Commissioners International, Inc, in the policing of drug use in horses competing in events under their control.
Narcotics and local anesthetics. The recognition and alleviation of animal pain is a growing veterinary and public concern. Pain can be of an acute or chronic nature with different behavioral manifestations. Physiologically, pain is a dynamic and complex phenomenon that produces changes in the central and autonomic nervous systems as well as in the endocrine system. Horses and other animals appear to possess an endogenous pain-suppressing system involving the brainstem and spinal cord. This system can modulate pain perception and the responses to it. The recently discovered endogenous opioid peptides (endorphins and enkephali...
Equine plasminogen polymorphism: allelic frequencies in 23 breeds. A modified procedure for detection of the two alleles of equine plasminogen using Western blotting methods following polyacrylamide gel isoelectric focusing is described. Gene frequencies in 23 breeds and Equus przewalskii are provided.
Sonographic brightness of the flexor tendons and ligaments in the metacarpal region of horses. Sonographic observations were made of the image mean gray scale (MGS) of the flexor tendons and ligaments in the left and right metacarpal regions of each of 10 clinically normal horses. In images made in the dorsal and sagittal planes, the MGS was measured at multiple sites in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament (AL), and suspensory ligament (SL), and at single sites in the medial and lateral limbs of the SL, and the palmar ligament. Relative sonographic brightness of each tendon and ligament was calculated by dividing the value ...
Granulomatous enteritis and cutaneous arteritis in a horse. A 5-year-old Quarter Horse mare was examined because of weight loss of 2 months' duration. The horse was anemic and in poor body condition, and had several areas of cutaneous ulceration, including areas on the muzzle and distal portion of the limbs. Histologic examination of a rectal mucosa biopsy specimen revealed a lymphoplasmacytic infiltrate in the lamina propria mucosa. Results of a glucose absorption test were suggestive of malabsorption. Histologic examination of a biopsy specimen from the cutaneous lesions revealed pronounced arteritis, and weak, patchy immunofluorescent staining for i...
Cardiopulmonary and behavioral responses to computer-driven infusion of detomidine in standing horses. Cardiopulmonary and behavioral responses to detomidine, a potent alpha 2-adrenergic agonist, were determined at 4 plasma concentrations in standing horses. After instrumentation and baseline measurements in 7 horses (mean +/- SD for age and body weight, 6 +/- 2 years, and 531 +/- 48.5 kg, respectively), detomidine was infused to maintain 4 plasma concentrations: 2.1 +/- 0.5 (infusion 1), 7.2 +/- 3.5 (infusion 2), 19.1 +/- 5.1. (infusion 3), and 42.9 +/- 10 (infusion 4) ng/ml, by use of a computer-controlled infusion system. Detomidine caused concentration-dependent sedation and somnolence. The...
Effects of diet and hindgut defaunation on diet digestibility and microbial concentrations in the cecum and colon of the horse. The effects of diet and hindgut defaunation (removal of protozoa from the hindgut) on diet digestibility (Trial 1) and on total and cellulolytic bacterial and fungal concentrations in the cecum and colon (Trial 2) were investigated. A high-forage (HF) diet, 90% alfalfa hay-10% concentrate, or a higher-concentrate (HC) diet, 60% alfalfa hay-40% concentrate, was limit-fed. In Trial 1, defaunation resulted in a slight decrease in DM digestibility (P < .1) and had no effect on cellulose digestibility. Dry matter digestibility was higher (P < .001) with the HC diet; however, no differences were obs...
Effects of atropine on the arrhythmogenic dose of dobutamine in xylazine-thiamylal-halothane-anesthetized horses. We investigated the influence of parasympathetic tone on the arrhythmogenic dose of dobutamine in horses premedicated with xylazine, anesthetized with guaifenesin and thiamylal, and maintained on halothane in oxygen. Six horses were used in 12 randomized trials. In each trial, after end-tidal halothane concentration was stabilized at 1.1% (1.25 times minimum alveolar concentration [MAC]) in oxygen, either saline solution (0.02 ml/kg of body weight) or atropine (0.04 mg/kg) was administered IV. Five minutes later, dobutamine infusion was started at dosage of 2.5 micrograms/kg/min, IV. The dobut...
Kinetic analysis of D-xylose absorption after its intragastric administration to mares deprived of food. Multicompartmental analysis was applied to study the kinetics of D-xylose distribution after its intragastric administration to healthy mares deprived of food for 12, 36, 72, and 96 hours. Disposition of D-xylose was described by a 5-compartment model. Maximal plasma D-xylose concentration was similar for 12 and 36 hours of food deprivation and was greater (P = 0.0001) than the values for 72 and 96 hours. Peak concentration of D-xylose appeared progressively later as food deprivation proceeded (P = 0.0001). Fractional rate of transfer (k1,6) was less after 96 hours of food deprivation, compare...
Pharmacokinetics of metronidazole after rectal administration in horses. Five healthy adult mares and 1 gelding were given a single dose (15 mg/kg of body weight) of metronidazole per rectum. After manual evacuation of feces from the rectum, a suspension of crushed tablets and water (40 ml) was administered via a 28-F catheter advanced 30 cm into the rectum. Blood samples were obtained by jugular venipuncture, and metronidazole concentration was measured serially for the 14 hours after drug administration. Mean serum concentration of metronidazole peaked at 4.5 micrograms/ml, 0.83 hour after administration, and decreased to 0.38 microgram/ml, 14 hours after adminis...
Pharmacokinetics of phenylbutazone in neonatal foals. Single doses (2.2 mg/kg of body weight) of phenylbutazone (PBZ) were administered IV to 6 neonatal horses (5 to 17 hours old at time of dosing). Plasma concentrations of PBZ and its metabolite oxyphenbutazone were monitored serially for 120 hours after drug administration. Pharmacokinetic variables were calculated, using 1- and 2-compartment open models. Descriptive equations from the best model for each foal were then used to derive model-independent variables describing PBZ disposition. Median volume of distribution at steady-state was 0.274 L/kg (range, 0.190 to 0.401 L/kg). Median terminal...
Pharmacokinetics of and serum thromboxane suppression by flunixin meglumine in healthy foals during the first month of life. Age and species reportedly affect the pharmacokinetic variables of nonsteroidal anti-inflammatory drugs. We determined the effect of age on flunixin pharmacokinetic variables in foals during the first month of life. We also estimated the physiologic activity of the drug in neonatal foals by determining the effect of flunixin on thromboxane production during clotting of blood taken from the foals. Flunixin disposition and clearance were determined after IV administration of 1.1 mg of drug/kg of body weight to 5 healthy foals when they were 24 to 28 hours, 10 to 11 days, and 27 to 28 days old. T...
Effects of sympathomimetic and sympatholytic drugs on exercise performance. This article has presented information on the importance of the sympathetic nervous system in the response to exercise. The authors have reviewed the very limited information on the effects of sympathomimetic and sympatholytic drugs on exercise performance in the horse. Most of these drugs are specifically prohibited under the rules of racing, and they have significant side effects that either decrease performance or make their use dangerous to both the horse and horse-man. Additionally, all of these drugs or their metabolites are readily detected by current drug testing protocols. Further inf...
A survey of neurological diseases in horses. Case records of 450 horses with signs of neurological disease are reviewed. One hundred and nineteen horses with neurological disease due to trauma were examined, of which 60 were due to spinal cord trauma, 47 to brain or cranial nerve trauma and 12 to peripheral nerve trauma. Cervical vertebral fractures/trauma were the most common injury. Basisphenoid/basioccipital bone fractures were the most common form of cranial trauma and facial nerve paralysis the most common cranial nerve injury. Eighty-nine horses with neurological disease due to malformation were examined. Cervical vertebral malform...
