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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.
Effects of flunixin on movement and performance of standardbred trotters on the track. An often discussed and controversial issue is the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on performance. The purpose of this study was to investigate the effect of the NSAID flunixin on the movement pattern and performance capacity of Standardbred trotters using a standardised track model. Five adult Standardbred horses in training trotted at 2 occasions with a 2 week interval on the same oval dirt track. Before each occasion the horses were either injected with flunixin meglumine (Finadyne) or normal saline solution i.m. 4 h before the performance test (double blind crossover...
The effect of dietary fibre on hydration status after dehydration with frusemide. Three diets were fed to 6 horses in a 3 x 6 Latin rectangle experiment to determine if dietary fibre could improve hydration status in response to dehydration with frusemide. Frusemide was used to simulate dehydration from exercise-induced sweat loss. Diets contained similar dry matter (DM), energy, protein and electrolyte content, but differed in total dietary fibre (TDF) and/or soluble fibre (SDF). The 3 diets were: 1) HIGH-HIGH (high TDF, high SDF); 2) HIGH-LOW (high TDF, low SDF); and 3) LOW-LOW (low TDF, low SDF). In each 10 day period, water intake and faecal moisture content were assess...
Skeletal muscle Na(+)-K(+)-ATPase and K+ homeostasis during exercise: effects of short-term training. The objective of this study was to determine the effects of 10 consecutive days of moderate intensity training on 1) the concentration of middle gluteal muscle Na(+)-K(+)-ATPase as determined by vanadate-facilitated 3H[ouabain binding; and 2) plasma potassium regulation before, during and after exercise at 100% of the pre-training maximum rate of oxygen consumption (VO2max). Six mature, unfit Thoroughbred horses completed both incremental (for determination of VO2max) and high-intensity exercise protocols before (HI1) and after (HI2) training. There additional horses undertook no training or e...
Skeletal myosin heavy chain composition and carriage training. Three different myosin heavy chain (MHC) isoforms have been identified in the equine gluteus medius muscle: the slow or MHC-I and the 2 fast MHC-IIA and MHC-IIX isoforms. They are distributed in 3 fibre types containing a single MHC (I, IIA, IIX) and 2 hybrid types co-expressing 2 isoforms (I + IIA, IIA + IIX). The aim of this study was to determine if heavy carriage training alters skeletal MHC composition in horses. Fourteen Andalusian mares age 42-46 months were used. Seven horses were used as controls to estimate the effects of growth on muscle. The remaining 7 horses underwent a training ...
Frusemide and weight carriage alter the acid:base responses of horses to incremental and to brief intense exertion. We speculated that frusemide would attenuate the acidosis associated with intense exertion, and that weight carriage would mitigate this effect. Therefore, in each of 2 experiments we measured pulmonary artery and systemic arterial blood pH, PCO2, PO2 and pulmonary artery temperature in 9 horses during exertion on a treadmill after each of 3 treatments. The treatments were: 1) injection of saline solution (C), 2) injection of frusemide (1 mg/kg bwt, i.v. 4 h before running) (FU) and 3) injection of frusemide (F) as for FU and the horses carried weight equal to that lost in the 4 h after frusem...
Effects of pre-exercise frusemide administration and post exercise anaesthesia on cardiopulmonary and acid-base parameters and blood and plasma volumes in horses exercised supramaximally to fatigue. Six horses were randomly assigned to receive either frusemide (F) (0.5 mg/kg i.v.) or an equivalent volume of saline (S) i.v., 4 h prior to treadmill exercise. Horses were instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP), and diastolic (DAP) carotid arterial pressures, pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), blood gases, and cardiac output (CO). Plasma (PV) and blood volumes (BV) were measured using 2 injections of Evan's Blue dye. Baseline parameters were recorded while the horse stood quietly. Hor...
Changes in left ventricular dynamics during graded exercise. Three mature Thoroughbred horses were prepared surgically with ultrasonic sonomicrometer crystals affixed to their ventricular pericardia. Signals from crystals recorded dimensions of axes across the left ventricle. Cubic algorithms were fitted to dimensional data to generate volume estimates that matched stroke volumes simultaneously measured using the Fick principle. As horses stood at rest or exercised at various intensities (approx 7, 12, 24, 47 and 100% maximal rate of O2 consumption VO2max[), left ventricular dimensions were recorded and 20 consecutive diastolic and systolic volumes calc...
Environmental stress and 3-day eventing: effects of altitude. 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...
Effect of inhaled beta 2 adrenoceptor agonist, albuterol sulphate, on performance of horses. This study was designed to test the hypothesis that a specific beta 2 adrenergic receptor agonist, albuterol sulphate, when delivered by metered-dose inhaler (MDI) would affect the performance of Thoroughbred horses during incremental exercise testing. Six conditioned Thoroughbred horses were randomly assigned to one of 2 treatment groups: Group 1 horses received placebo and Group 2 received albuterol. Each horse received both treatments in a crossover design with a 3 week interval between trials. Horses inspired albuterol (900 micrograms) or placebo over a 5 min period followed by an incremen...
Treadmill exercise-induced tendon hypertrophy: assessment of tendons with different mechanical functions. The equine superficial digital flexor tendon (SDFT) functions as an energy store during high-speed gaits reducing the energetic cost of locomotion. To enable the SDFT to function effectively, the appropriate mechanical properties are essential. We tested the hypothesis that the SDFT does not undergo gross hypertrophy in response to high-intensity exercise whereas tendons not involved in energy storage undergo adaptive hypertrophy. Two groups (n = 6) of Thoroughbred fillies were trained at high-intensity on a high-speed equine treadmill for 5 months (short-term study) or 18 months (long-term st...
Effect of exercise and COPD crisis on isoprostane concentration in plasma and bronchoalveolar lavage fluid in horses. To test whether isoprostanes could be used as markers of oxidative stress in horses, their concentration was determined in plasma and in pulmonary epithelial lining fluid (PELF) in 3 models of oxidative stress: (1) strenuous exercise, (2) acute COPD crisis and (3) exercise combined with COPD crisis. Four horses were investigated twice, once in crisis and once in remission. The animals underwent a standardised treadmill exercise test. Isoprostane assessment was performed in plasma and bronchoalveolar lavage fluid 24 h before and 1 h after exercise and in plasma also immediately after exercise. ...
An MRI study of the effect of treadmill training on bone morphology of the central and third tarsal bones of young thoroughbred horses. Training results in marked modelling of the subchondral bone of the carpus, but the effect of training on the subchondral bone of the distal tarsal joints is unknown. The aim of this study was to determine whether training influenced modelling of the third and central tarsal bones in Thoroughbred horses. Twelve untrained Thoroughbred horses were divided into 2 groups. Group 1 underwent a 19 week progressive training regimen on a high speed treadmill. Group 2 were walked for 40 min daily. Images of left tarsi were obtained by magnetic resonance imaging (MRI) with a 0.5 Tesla superconducting mag...
Haematological and biochemical responses to training and overtraining. We sought a physiological marker of overtraining in horses, using commonly practised field and laboratory tests to allow early prediction and treatment of the syndrome. Thirteen Standardbred horses were trained as follows: phase 1 (endurance, 7 weeks), phase 2 (high intensity, 9 weeks) and phase 3 (overload, 18 weeks). In phase 3 the horses were divided into 2 groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies and durations than the C group. Overtraining occurred after 31 weeks and was defined as a significant decrease in treadmill run ...
Effects of low- and moderate-intensity training on metabolic responses to exercise in thoroughbreds. This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for e...
The effects of a rider’s mass on ground reaction forces and fetlock kinematics at the trot. Ground reaction force (GRF) measurements are often normalised to body mass to facilitate inter-individual comparisons. The objective of this study was to explore the effect of a rider on the GRFs and fetlock joint kinematics of trotting horses. The subjects were 5 dressage-trained horses and 3 experienced dressage riders. Ground reaction force measurements and sagittal view videotapes were recorded as the horses trotted at the same velocity in hand (3.49 +/- 0.52 m/s) and with a rider (3.49 +/- 0.46 m/s). Data were time-normalised to stance duration. Ground reaction force measurements were exp...
A preliminary study of the effect of inhaled nitric oxide on lung mechanics in the standing horse with histamine-induced bronchoconstriction. The effect of inhaled nitric oxide on pulmonary mechanics was studied in normal standing horses with histamine-induced bronchoconstriction. The respiratory health status of 6 normal horses was established on the basis of history, clinical and bronchoalveolar lavage examination. Intrathoracic pressures were estimated using distal oesophageal pressures. Respiratory gas flows were measured using a heated pneumotachograph. Pulmonary mechanics variables were determined from these measurements on a breath by breath basis. Bronchoconstriction was induced by nebulizing a 0.75% w/v solution of histamin...
Endocrine response to exercise in young and old horses. Six young (mean + s.e., 5.3 +/- 0.8 years, 445 +/- 13 kg bwt) and 6 old (22.0 +/- 0.4 years, 473 +/- 18 kg bwt) Standardbred and Thoroughbred mares were used to test the hypothesis that age would alter the endocrine response to exercise. All of the mares were unconditioned but accustomed to the laboratory, to standing quietly and running on a treadmill, and to the standardised incremental exercise test (SET) used in the experiment. Two weeks prior to the experiment, each horse underwent a SET to determine maximal oxygen uptake (VO2max) and the speeds to be used in the actual experiment. A seco...
Hyperbolic relationship between time-to-fatigue and workload. The power:time-to-fatigue relationship for high-intensity exercise in man is useful in determining anaerobic work capacity. The purpose of this study was to determine the nature of this relationship in horses. Eight Standardbred horses performed 5 or 6 run-to-fatigue trials on a treadmill. Exercise intensities were chosen to induce fatigue in 30 to 240 s. The order of trials was randomised for each horse, but balanced overall for the first 4 trials. The data for power (independent variable) and time-to-fatigue (dependent variable) were tested for goodness of fit to hyperbolic, linear and expon...
Heritability of percentage of fast myosin heavy chains in skeletal muscles and relationship with performance. The purpose of this study was to determine the percentage of fast myosin heavy chains (fast MHCs = MHC 2A + 2B) in 2 propelling muscles to estimate the heritability and to identify any relationship with performance. The gluteus medius and the biceps femoris muscles were biopsied in 100 related French Anglo-Arabian horses. The percentages of slow and fast myosin heavy chains were measured using an ELISA technique. The heritability (s.e.) of the fast MHCs percentage was estimated at 13% (0.1) using a restricted maximum likelihood resolution of a mixed animal model. There were significant (P < 0....
Contributions of equine exercise physiology research to the success of the 1996 Equestrian Olympic Games: a review. Following public concern about the weather conditions for the 1996 Olympic Games in Atlanta an international research programme was initiated. The primary objective of this effort was to identify strategies for ensuring welfare of horses competing in the heat. Field observations of horses during the endurance test of 3-day events in Europe, Canada, and the USA characterised the work effort of this form of competition; laboratory treadmill studies assessed limitations to performance of heat and humidity, explored the relationships of thermoregulatory demands to the phases of the competition and...
Pulmonary vascular resistance of horses decreases with moderate exercise and remains unchanged as workload is increased to maximal exercise. This study was carried out to examine changes in pulmonary vascular resistance (PVR) induced by moderate and strenuous exercise; the objective being to understand why pulmonary artery blood pressure of exercising horses increases progressively as work intensity increases. Pulmonary arterial and wedge pressures (referenced at the point of the left shoulder) were determined simultaneously with cardiac output in 2 groups of healthy, sound, exercise-trained horses. Horses in Group 1 (n = 8) were studied at rest and during exercise performed at 8 and 13 m/s; the latter workload eliciting maximal he...
The effect of training on the calcified zone of equine middle carpal articular cartilage. Carpal osteochondral injury is frequently observed in strenuously trained horses. It is clear that the integrity of articular cartilage and subchondral bone are intimately related, although there is controversy about which component is the most important. Calcified cartilage provides the mechanical link between soft hyaline cartilage and stiff subchondral bone so it is essential to understand the tissue's response to exercise. Middle carpal calcified and uncalcified (hyaline) cartilage thickness was investigated in horses undergoing high- and low-intensity exercise. Twelve untrained horses (18...
A comparison of grain, oil and beet pulp as energy sources for the exercised horse. High-grain diets for the exercising horse were compared with diets which provided 15% of the total caloric intake from either vegetable oil or a highly fermentable fibre source (beet pulp). Six Thoroughbreds age 3 years were fed one of 3 diets or 5 weeks in a replicated 3 x 3 Latin square. The CONTROL diet was 3.65 kg of sweet feed (SF), 0.9 kg of a protein/vitamin/mineral pellet and 5.45 kg of hay cubes. The FAT diet replaced 1.15 kg of SF with 0.45 kg of soybean oil and the FIBRE diet replaced 1.15 kg of SF with 1.36 kg of beet pulp. Horses were exercised 3 times per week on a high-speed tre...
Relationship of body condition score to completion rate during 160 km endurance races. Three-hundred and sixty horses, primarily of Arabian breeding, age 5-22 years and body conditions scores 1.5-5.5 (on 1 to 9 scale as described by Henneke 1985), participated in one of two 160 km endurance races over the same course in August 1995 and July 1996. Condition score, cannon bone circumference, combined rider and tack weight, heart girth and body length were measured 11-18 h prior to the start of the event and bodyweight estimated according to the formula by Carroll and Huntington (1988). A rider weight ratio was calculated as rider weight divided by horse bodyweight. Rider weight an...
The recovery of horses from inhalant anesthesia: a comparison of halothane and isoflurane. Recovery is one of the more precarious phases of equine general anesthesia. The quality and rate of recovery of horses from halothane and isoflurane anesthesia were compared to determine differences in the characteristics of emergence from these commonly used inhalant anesthetics. Methods: Prospective, randomized blinded clinical trial. Methods: A total of 96 Thoroughbred and 3 Standardbred racehorses admitted for elective distal forelimb arthroscopy. Methods: All horses were premedicated with intravenous xylazine, induced with guaifenesin and ketamine, and maintained on a large animal circle ...
Evaluation of a bioresorbable hyaluronate-carboxymethylcellulose membrane for prevention of experimentally induced abdominal adhesions in horses. To evaluate the efficacy of a bioresorbable hyaluronate-carboxymethylcellulose membrane (HA-membrane) for prevention of experimentally induced abdominal adhesions in horses. Methods: Experimental study. Methods: Twelve healthy adult horses. Methods: The effect of an HA-membrane on adhesion formation was evaluated in 12 healthy horses using an established model of serosal trauma to induce adhesions. A ventral median celiotomy and two jejunal resections and end-to-end anastomoses were performed. Two separate jejunal areas were abraded, and three 2-0 chromic gut sutures placed in the abraded area...
[Functional morphology of the large intestinal mucosa of horses (Equus przewalskii f. caballus) with special regard to the epithelium]. The mucous membrane of the caecum and colon ascendens of adult horses was first studied using light and transmission electron microscopy. In the surface epithelium there was an inconspicuous constellation of organelles, otherwise there was a lot of mitochondria as a source of energy for absorptive performances. Moreover, enlarged intercellular spaces exist as an indication of an increased uptake of water and electrolytes. In the basal region of Lieberkühn's crypts there were single enteroendocrine cells and numerous granules in the apical epithelial cytoplasm. The functional meaning of these ...
The teeth of the horse: evolution and anatomo-morphological and radiographic study of their development in the foetus. The aim of this work was to study the ontogenetic process in teeth from their early appearance in the ossifying matrix of the mandible and maxilla, in different foetuses of scalar ages. Radiographic examinations of the skull and mandible hemisections were performed and the latero-medial (LM) and dorsoventral (DV) projections for the skull and mandible were analysed. A high-definition film-screen combination was used for this study. The exposure values ranged from 35 kV/6 mAs to 58 kV/10 mAs, according to the size of the skulls and their degree of ossification. The first dental germ observed wa...
Sonographic observations of the peripheral vasculature of the equine thoracic limb. 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...
