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Topic:Equine Science
Equine Science encompasses the study of horses and their management, health, and performance. This field integrates various scientific disciplines such as biology, genetics, nutrition, physiology, and veterinary medicine to understand and improve the well-being and capabilities of horses. Areas of focus include equine anatomy, reproduction, behavior, and disease prevention. Research in equine science aims to enhance horse care, optimize training and performance, and address health challenges. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine science, providing insights into the latest advancements and methodologies in the field.
Cold air-induced late-phase bronchoconstriction in horses. Inspired air is warmed to body temperature and fully humidified by the upper airway mucosa under normal resting conditions. This conditioning process may not be completed by the upper airways during conditions of increased minute ventilation or when the inspired air is unusually cold, resulting in cooling and desiccation of lower respiratory surfaces. Excess heat and water loss from intrapulmonary airways is believed to be the provocative stimulus for exercise-induced bronchoconstriction (occurring immediately after exercise) and associated late phase airway obstruction (occurring a few hours ...
Thyroid hormone responses to endurance exercise. Limited information exists about changes in circulating thyroid hormone concentrations during prolonged endurance exercise in horses. Objective: To examine the effects of prolonged exercise on serum iodothyronine concentrations in horses performing endurance exercise of varying distances. Methods: Serum concentrations of iodothyronines were measured in horses before and after completion of 40, 56, 80 and 160 km endurance rides (Study 1); daily during a 5 day, 424 km endurance ride (Study 2); and before and for 72 h after completion of a treadmill exercise test simulating a 60 km endurance ride...
Recruitment pattern of muscle fibre type during flat and sloped treadmill running in thoroughbred horses. There is little information about the muscle fibre recruitment pattern during sloped and flat track running in Thoroughbred horses. Objective: To examine the glycogen depletion pattern of each muscle fibre type during running on a flat and sloped treadmill. Methods: Thirteen Thoroughbred horses (3-9 years old) were used. They were initially subjected to incremental exercise tests on a treadmill at 10 and 0% inclines in each horse to determine running speed at 90 and 60% VO2max. Needle biopsy samples were obtained from the middle gluteal muscle immediately after the running at 90% VO2max for 4 ...
Measurements of fitness in thoroughbred racehorses using field studies of heart rate and velocity with a global positioning system. Field based studies of changes in fitness are difficult to conduct in galloping Thoroughbreds. Measurements of heart rate (HR) and real time velocity with a global positioning system (GPS) could provide a method for routine field studies of fitness. Objective: To investigate measurements of fitness in the field without using multiple, standardised steps of increasing velocity in the exercise test. Methods: Twelve healthy 3- to 5-year-old Thoroughbreds were used in the study of reliability, and twelve 2-year-old Thoroughbreds in the investigation of the effect of training. Five second averages ...
Heart rate responses during acclimation of horses to water treadmill exercise. The use of water treadmill exercise in horses is popular, although little is known about the physiological responses to this form of exercise. No information exists regarding the time taken to acclimate to water treadmill exercise compared to that of high-speed treadmill exercise, for both physiological and biomechanical parameters. Objective: To determine heart rate responses during acclimation to water treadmill exercise with and without sedation on first time exposure. Methods: All horses were exercised on a water treadmill at the walk for 15 min once a day for 4 days. Fourteen horses (mean...
MCT1 and CD147 gene polymorphisms in standardbred horses. Transport of lactate across membranes is facilitated by proton-monocarboxylate transporters (MCT). The most widely distributed isoform is MCT1, which needs an ancillary protein CD147. Studies on erythrocytes have shown that high activity of MCT1 is inherited as the dominant allele and that activity is regulated through CD147. Mutations of human MCT1 have been described that appear to impair lactate transport in muscles and cause exertional rhabdomyolysis. There are no reports of this potential relationship in the horse. Objective: To obtain sequences of equine MCT1 and CD147 to examine differe...
Optimal active recovery intensity in standardbreds after submaximal work. A retrospective study concerning spontaneous active recovery intensity, i.e. at a freely chosen speed, after a submaximal exercise in trotters showed that the mean intensity demanded by trainers corresponds to 40-50% of maximal heart rate (max HR; unpublished data). However, in human athletes, optimal active recovery intensity was found to be about 60-70% of max HR. Is the spontaneous recovery optimal after a submaximal exercise in trotters? Objective: To compare different recovery intensities and define the most efficient one. Methods: Thirty-seven trotters performed a standardised exercise t...
Double blind investigation of the effects of oral supplementation of combined glucosamine hydrochloride (GHCL) and chondroitin sulphate (CS) on stride characteristics of veteran horses. Oral chondroprotective supplements are commercially popular for veteran (and other athletic or arthritic) horses prone to joint degeneration, yet lack conclusive scientific support. Objective: To quantify the effects of an oral joint supplement (combination glucosamine hydrochloride (GHCL), chondroitin sulphate (CS) and N-acetyl-D-glucosamine) in vivo on stride parameters of veteran horses. Methods: Twenty veteran horses were randomly assigned to a treatment (n = 15) or placebo group (n = 5). Pre-treatment gait characteristics were recorded at trot using digital video footage (50 Hz). The rang...
Validation of a portable equine metabolic measurement system. In equine sports medicine, VO2 has been measured exclusively with stationary systems, in laboratories equipped with a treadmill. Measurement during exercise in field conditions has not previously been reported because of the lack of portable equipment designed for horses. Objective: A commercially available portable metabolic measurement system, based on breath-to-breath gas analysis and flow spirometry, was adapted to the horse's physiology and morphology (Cosmed K4b2 and Equimask) and its validity tested by (1) repeatability of the measures and (2) comparing metabolic data to those obtained ...
Influence of training on plasma adrenaline and noradrenaline kinetics in untrained standardbreds. Catecholamines (CAT) play an important role in modulating the response to exercise. But the kinetics of CAT changes during exercise are difficult to study due to their short biological half-life. Objective: Learning about variations in plasma CAT levels during training could furnish new information regarding sweating, redistribution of blood flow and energy metabolism. Methods: Four untrained Standardbreds, adapted to treadmill work, were used to determine the influence of training on plasma adrenaline (A) and noradrenaline (NA) kinetics. Horses underwent a standardised exercise test (SET) on ...
Gene expression profiling in equine muscle tissues using mouse cDNA microarrays. Progress could be achieved by using microarrays to understand metabolic adaptations and disorders in equine muscle in response to exercise. Objective: To test the feasibility of using mouse cDNA microarrays to analyse gene expression profile in normal equine muscles. Methods: Muscular biopsies of dorsal gluteus medius and longissimus lumborum were done in 4 healthy Standardbreds. Total RNA was extracted from the muscle samples. The concentration and quality of RNA were measured before and after amplification. Gene expression profiles were measured using mouse cDNA microarrays including 15,264 ...
Effect of head and neck position on vertical ground reaction forces and interlimb coordination in the dressage horse ridden at walk and trot on a treadmill. Little is known in quantitative terms about the influence of different head-neck positions (HNPs) on the loading pattern of the locomotor apparatus. Therefore it is difficult to predict whether a specific riding technique is beneficial for the horse or if it may increase the risk for injury. Objective: To improve the understanding of forelimb-hindlimb balance and its underlying temporal changes in relation to different head and neck positions. Methods: Vertical ground reaction force and time parameters of each limb were measured in 7 high level dressage horses while being ridden at walk and tr...
Method for quantifying net anaerobic power in exercising horses. There is no good method for measuring net anaerobic power in exercising horses to allow accurate estimates of total metabolic power. Objective: The increase in VO2max when breathing hyperoxic (HO) gas should be accompanied by a stoichiometrically equal (in terms of ATP turnover, i.e. energy equivalents) decrease in plasma lactate accumulation rate (Mlactate). Methods: Six 3-year-old Thoroughbreds were trained on an equine treadmill wearing a semi-open flow mask for measurement of VO2. After 4 months the horses ran with reproducible specific VO2max (VO2max/kg bwt). The mask design allowed mixin...
Utilisation of the time constant calculated from heart rate recovery after exercise for evaluation of autonomic activity in horses. Heart rate (HR) recovery immediately after exercise is controlled by autonomic functions and the time constant (T) calculated from HR recovery is thought to be an index of parasympathetic activity in man. Objective: To investigate whether it is possible to evaluate autonomic function using the time constant in horses. Methods: Five Thoroughbred horses were subjected to a standard exercise test. Following pre-medication with saline, atropine and/or propranolol, the horses ran for 2.5 min at a speed of 8 m/sec at a 10% incline and T was calculated from HR after the exercise. Secondly, 7 Thorough...
Effects of short-term training on insulin sensitivity and skeletal muscle glucose metabolism in standardbred horses. Increased insulin sensitivity occurs after a period of exercise training, but the mechanisms underlying this training-associated increase in insulin action have not been investigated. Objective: To examine the effects of short-term endurance training (7 consecutive days) and a subsequent period of inactivity (5 days) on whole body insulin sensitivity and GLUT-4 protein and the activities of glycogen synthase (GS) and hexokinase (HK) in skeletal muscle. It was hypothesised that training would increase insulin sensitivity in association with increased GLUT-4 protein and activities of GS and HK, ...
The effect of gallop training on hoof angle in thoroughbred racehorses. The economic impact of soundness problems in racehorses is very high and low hoof angle at the toe has been associated with a lack of soundness. However, it is not clear what environmental and management factors might contribute to a low hoof angle. Objective: To investigate the hypothesis that the hooves of racehorses become flatter when in gallop training, as well as to determine factors contributing to this trend. Methods: Weekly hoof measurements were taken with a hoof gauge from 45 Thoroughbred racehorses; 4 Thoroughbred show horses kept in consistent conditions and shod by the same farri...
A nonsurgical method allowing continuous core temperature monitoring in mares for extended periods, including during endurance exercise. Body temperature can be a useful measure of how well the horse responds to thermal challenges of exercise and environment. Currently there is little information available about how body temperature changes throughout an endurance ride, and no nonsurgical methods to evaluate internal temperature of exercising horses during prolonged periods and during long distances. Objective: To develop and test a nonsurgical method, using temperature loggers, of continuously recording internal temperature during exercise and over an extended period. Methods: Loggers were inserted transcervically into the ute...
Effects of dietary energy source and physical conditioning on insulin sensitivity and glucose tolerance in standardbred horses. There is evidence that adaptation to diets rich in nonstructural carbohydrates (NSC) contributes to the development of insulin resistance in horses. To date, however, no study in horses has examined the effects of physical conditioning on diet-associated alterations in insulin sensitivity and glucose tolerance. Objective: To examine the effects of adaptation to concentrate feeds rich in NSC or fat on insulin sensitivity and glucose tolerance in horses, both in the sedentary state and after a subsequent period of physical conditioning. Methods: Fourteen mature Standardbred horses underwent both...
Correlation of race earnings with velocity at maximal heart rate during a field exercise test in thoroughbred racehorses. Running ability of Thoroughbred racehorses is correlated with maximal oxygen uptake, and the velocity at maximal oxygen uptake is highly correlated with the velocity at maximal heart rate (VHRmax). Objective: To investigate the relationship between VHRmax and racing performance, expressed as 'peak dollars earned per race start'. Methods: Heart rate (HR) and velocity were recorded in 25 Thoroughbred racehorses during trotting and subsequent fast gallops in the field at velocities of 15-16 m/sec. Velocity was recorded by a global positioning system (GPS). Maximal HR (HRmax) and maximal velocity ...
An echocardiographic and auscultation study of right heart responses to training in young national hunt thoroughbred horses. There are few data available to determine the effect of training on cardiac valve function. Objective: To investigate the effect of commercial race training on right ventricular (RV) and tricuspid valve function in an untrained group of National Hunt Thoroughbreds (TB). Methods: Cardiac auscultation, guided M-mode echocardiography of the RV, and colour flow Doppler (CFD) tricuspid valve and right atrium were performed in 90 TB horses (age 2-7 years) 1998-2003. Forty horses were examined at least once and 48 horses were examined on at least 2 occasions. Examinations were then classified as: i) ...
Is the distribution of selenium and zinc in the sublocations of spermatozoa regulated? In the sperm nuclei, of mammalian species selenium has been found only in the form of sperm nuclei glutathione peroxidase (snGPx) where it is most likely bound to the chromatin of spermatozoa. Over 80% of selenium in sperm is bound to the selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the midpiece of rat sperm. Zinc in sperm is mainly contained in the outer dense fiber (ODF) proteins of the flagella of mammalian spermatozoa. In the sperm nuclei, zinc is predominately located in the chromatin to the protamine proteins. In order to investigate if the insertion of zinc...
The effect of long-term exercise on glucose metabolism and peripheral insulin sensitivity in standardbred horses. To study the possible long-term effect of improved glucose tolerance in horses after long-term training, as the impact of exercise training on glucose metabolism is still unclear in the equine species. It is not known whether there is a direct long-term effect of training or if the measurable effect on glucose metabolism is the residual effect of the last exercise session. Objective: To determine the chronic effect on glucose metabolism and peripheral insulin sensitivity of long-term training in horses by use of the euglycaemic hyperinsulinaemic clamp technique. Methods: Eleven Standardbred ho...
Does usefulness of potassium supplementation depend on speed? Electrolyte mixtures given to counter sweat loss usually contain abundant potassium. However, increases in plasma [K+] occur with exercise and supplementation may further increase plasma levels, potentially increasing the risk of neuromuscular hyperexcitability and development of adverse clinical sequellae. This proposition requires study. Objective: To compare effects of a K-rich electrolyte supplement (EM+K) to a K-free one (EM-K) on plasma [K+], [Ca++] and acid-base status during an endurance incremental exercise test on the treadmill. Methods: The test consisted of 3 bouts (simulating loop...
Effects of prior exercise on components of insulin signalling in equine skeletal muscle. Exercise is an important stimulus for the regulation of numerous metabolic functions in muscle, but there has been little investigation of the mechanism of exercise-enhanced glucose utilisation. Objective: To examine the effects of exercise on the signalling components Akt and glycogen synthase kinase-3 (GSK3) involved in insulin regulation of glycogen synthase (GS) activity. It was hypothesised that hyperinsulinaemia and prior exercise would alter the extent of Akt phosphorylation and GSK3beta deactivation and increase insulin stimulation of GS activity in skeletal muscle. Methods: Eight Stan...
Body composition in young standardbreds in training: relationships to body condition score, physiological and locomotor variables during exercise. Body composition is an essential factor in athletic performance of human sprinters and long distance runners. However, in horses, many questions remain concerning relationships between body composition and performance in the different equine activities. Objective: To determine relationships between body composition, body score, physiological and locomotor variables in a population of young Standardbreds in training. Methods: Twenty-four 2-year-old Standardbreds were studied, body condition on a scale 0-5 and bodyweight recorded, and height at withers measured. Percentage of fat (%F), fat mass ...
Exercise-induced pulmonary haemorrhage during submaximal exercise. Maximally exercising horses achieve mean pulmonary artery pressures (Ppa(mean)) that exceed the minimum threshold (75 mmHg) estimated for pulmonary capillary rupture and exercise-induced pulmonary haemorrhage (EIPH). EIPH is not expected to occur during moderate submaximal exercise (i.e. 40-60% VO2max) since Ppa(mean) remains well below this threshold. Objective: Prolonged submaximal exercise (trotting) would precipitate locomotory respiratory uncoupling and cause EIPH. This would be present as a result of the most negative intrapleural pressures (as estimated by the minimum oesophageal pressu...
The effect of physical exercise on the daily rhythm of platelet aggregation and body temperature in horses. The goal of this study was to investigate the influence of physical activity on the daily rhythm of platelet aggregation and body temperature in horses. Blood samples from 12 Thoroughbred horses, six sedentary animals and six athletes (studied both before and after a period of inactivity) were collected at 4h intervals for 48h via an intravenous cannula inserted into the jugular vein. Body temperature was recorded every 4h for 48h with a rectal probe. Platelet aggregation was measured with an aggregometer. Collagen was used to test the aggregation of the plasma samples. Statistical analysis of...
Inbreeding and genetic structure in the endangered Sorraia horse breed: implications for its conservation and management. The Sorraia horse is a closed breed with reduced effective population size and considered in critical maintained risk status. The breed exists in 2 main breeding populations, one in Portugal and one in Germany, with a smaller population size. A set of 22 microsatellite loci was used to examine genetic diversity and structure of the Sorraia horse breed and to compare individual inbreeding coefficient F, estimated from pedigree data, with individual heterozygosity and mean d(2). The Sorraia horse shows lower levels of microsatellite diversity when compared with other horse breeds. Due to managem...
Sexual behavior of mares. The mare is seasonally polyestrus, having an anovulatory period during the short light days of late fall and early winter, and beginning to ovulate as the days become longer during the winter. The complete estrus cycle is typically about 3 weeks, with 5 to 7 days of estrus and approximately 2 weeks of diestrus. When a mare lives within the natural social structure of the horse, i.e. a family band with several adult mares and one or more stallions, estrus is characterized by repeatedly approaching the stallion, frequent urination, deviating the tail away from the perineum, and standing still wi...
