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Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Effects of weight carrying, exercise and a myo-anabolic supplement on growth and muscle. Weight training is commonly used by human athletes to increase strength and fitness. This study was performed to examine the effect of weight-carrying and nutritional supplementation on muscle development and growth in young horses. This study examined the effect of weight-carrying and nutritional supplementation on muscle development and growth. Seventeen horses were divided into 3 groups: controls exercised in a free-flow exerciser, a weight group that performed the same exercise, carrying progressively increasing weight up to 45 kg, and a weight-supplement group, that also received a myo-an...
Relationship between body composition, blood volume and maximal oxygen uptake. It has long been known that body mass and, more specifically, lean body mass are strongly correlated with maximal oxygen uptake (VO2max) in man and animals. However, there are no data to date describing this phenomenon in the horse. The purpose of this paper is to examine the relationship between body composition and VO2max in the horse. Twenty-three healthy and unfit Standardbred mares performed an incremental exercise test (GXT) to measure VO2max. Rump fat thickness (RTH), a measure of fat covering, was measured using B-mode ultrasound. Plasma volume, total blood volume and red cell volume w...
A lactate-guided conditioning programme to improve endurance performance. Blood lactate measurements are used widely in horses to assess athletic performance, but there are few published data on using lactate as a guide for endurance improvement. The velocity at which blood lactate concentration ([LA]) of 4 mmol/l is reached (v4) is widely used to determine fitness. In an earlier study of v4, exercise at low intensities for longer duration was more effective at improving endurance than shorter, higher intensities. However, the prescription was unchanged during the study (6 weeks). We hypothesised that, to produce greater improvement in v4 in the same time frame, it ...
Speed associated with plasma pH, oxygen content, total protein and urea in an 80 km race. To test the hypothesis that endurance performance may be related quantitatively to changes in blood, we measured selected blood variables then determined their reference ranges and associations with speed during an 80 km race. The plan had 46 horses in a 2 x 2 factorial design testing a potassium-free electrolyte mix and a vitamin supplement. Blood samples were collected before the race, at 21, 37, 56 and 80 km, and 20 min after finishing, for assay of haematocrit, plasma pH, pO2, pCO2, [Na+], [K+], [Ca++], [Mg++], [Cl-], lactate, glucose, urea, cortisol, alpha-tocopherol, ascorbate, creatine ...
Changes in skeletal muscle GLUT4 content and muscle membrane glucose transport following 6 weeks of exercise training. This study examined changes in skeletal muscle GLUT4 content and glucose transport in isolated muscle membranes (GT) from horses before and 2 min after standardised submaximal exercise tests (SET) prior to and after completion of 6 weeks of training. Seven horses, age 3-9 years, body mass mean +/- s.e. 530 +/- 19 kg, and sedentary for at least 4 months, completed 6 weeks of training on a treadmill. An initial SET (UT) was performed on a 4 degree incline at a speed equivalent to 55% of pretraining VO2max and was repeated post-training at the same absolute workload (ABS). A third SET (REL) was p...
Effect of dorsal displacement of the soft palate on ventilation and airflow during high-intensity exercise. Dorsal displacement of the soft palate (DDSP) is one of the most common obstructive conditions of the upper respiratory tract in the racehorse. The present study was conducted to determine the effects of intermittent dorsal displacement of the soft palate (DDSP) on ventilation and respiratory airflow during high intensity exercise. Videoendoscopic recordings were made of the nasopharynx and larynx simultaneously with measurements of airflow and respiratory gas exchange, during high-speed treadmill exercise in 9 horses with confirmed intermittent DDSP admitted for clinical investigation of poor...
Chronic nodular panniculitis in a three-year-old mare. The clinical signs of chronic nodular panniculitis in a three-year-old mare were consistent with a diagnosis of sterile nodular panniculitis, but the mare had histopathological signs of both generalised steatitis and sterile nodular panniculitis. The mare was deficient in vitamin E and selenium.
Effect of trotting speed, load and incline on hindlimb stance-phase kinematics. The objective was to understand how the stance-phase kinematics of the hindlimb of trotting horses change with speed under 3 conditions (level, loaded and incline), to compare our results with the predictions of the spring-mass model and to help focus our future studies of muscle function. Video recordings were made of 5 Arabian horses trotting on a treadmill. Five consecutive strides were digitised and averaged for each trial. The angle-time diagrams were qualitatively similar to those reported previously. As speed increases, the range of motion of the hindlimb increases, as predicted by the ...
Effects of ageing and training on maximal heart rate and VO2max. The purpose of this study was to test the hypotheses that ageing would result in a decline in maximal heart rate (HRmax) and maximal aerobic capacity (VO2max) and, secondarily, that those effects would be reversible with training. Eighteen, healthy, unfit Standardbred mares representing 3 age groups: young (Y = mean +/- s.e. 6.8 +/- 0.4 years, n = 6); middle-aged (MA = 15.2 +/- 0.4 years, n = 6); and old (O = 27.0 +/- 0.2 years, n = 6) were used. HRmax, VO2max and oxygen pulse at VO2max (OPmax) and the velocities producing HRmax (VHRmax) and VO2max (VVO2max) were measured during pretraining an...
Hindlimb net joint energies during swing phase as a function of trotting velocity. Net joint powers and energies have been described in walking horses during the swing phase of the stride in the fore- and hindlimb (Clayton et al. 2001). During trotting, swing phase net joint powers have been described in the forelimb but not in the hindlimb. The effects of velocity on power profiles and energy patterns are important in relation to locomotor energetics. The objective of this study was to evaluate velocity-dependent changes in hindlimb net energy profiles of the swing phase during trotting. Inverse dynamic analysis was used to calculate net joint energies at the hindlimb joint...
Influence of trotting and supplemental weight on metacarpal bone development. The use of weight-training to alter bone strength has not been investigated in horses. Recognising that bone responds to loading, we studied the effect of carrying weight on bone development during training. Seventeen horses were divided into 3 groups: controls exercised counterclockwise in a free-flow exerciser; the weight group performed the same exercise carrying progressively increasing weight up to 45 kg and the weight supplement group also received a myo-anabolic supplement. Radiographic equivalence measure of bone mineral content of zones of the third metacarpi (MCIII) was determined on...
Structural and oxidative enzyme characteristics of the diaphragm. During exercise, the horse can achieve oxygen uptakes and ventilations in excess of 200 ml/kg/min and 1800 l/min, respectively. Whether the diaphragm has the capacity to contribute substantially to inspiratory effort in the exercising horse is not known. To investigate the potential for the horse diaphragm to generate tension, lung displacement and sustain ventilatory function, we measured diaphragm thickness, muscle length and oxidative enzyme activity (citrate synthase) within the ventral, medial and dorsal costal and crural diaphragm. In the diaphragms of 6 mature horses (5 Thoroughbreds, o...
Postprandial glucose and insulin responses to a postexercise grain meal. Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 ...
The cost of transport in an extended trot. We hypothesised that trotters during an extended trot have lower energetic costs of locomotion (CT) than horses not bred for this behaviour. VO2 was measured as a function of speed in 7 Arabian horses (3 trained to extend their trotting speeds) and in 2 horses, of similar mass, bred to trot (Hackney). Both oxygen consumption and CT increased with speed and there was, contrary to our hypothesis, no difference between breeds. In Arabians at 6.5 m/s, CT had increased 25% above the CT at 5.0 m/s (normal transition speed). For Hackneys at 6.8 m/s, the CT was almost 35% higher. Stride frequencies in...
Effects of substituting starch with fat on the acid-base and mineral status of female horses. Feeding a high-fat diet may have potential advantages by maintaining pH homeostasis during intense exercise; conversely, effects including elevated PCV and increased plasma concentration of total protein may indicate effects detrimental to performance by reducing perfusion of tissues and organs. Six horses were used to determine the effects of an replacement of starch (diet '0.00') with 0.33, 0.67, 1.00 and 1.33 g soybean oil/kg bwt/day (diets '033', '0.67', '1.00' and '1.33') on venous and renal acid-base status and fractional clearance (FC) of electrolytes in a postprandial state but prior t...
Biomechanical implications of uphill training on the aetiology of tendinitis. It has been reported that a small decrease in the strain in the superficial digital flexor tendon (SDFT) occurs if the toe is raised during walking. Although walking on a slope appears similar to raising the toe, it is unclear whether uphill exercise decreases the strain in the SDFT. Because the force or strain on tendons is one of the important factors leading to tendon stress injury, we hypothesised that reducing the force in the SDFT during exercise may prevent tendinitis. The purpose of this study was to determine the effects of treadmill inclination on the force in the SDFT in the walking...
Age-related changes and inheritance of lactate transport activity in red blood cells. In red blood cell membranes, the activity of the main lactate carrier, H+-monocarboxylate co-transporter (MCT), varies interindividually and its distribution is bimodal. To show the repeatability of MCT activity, 2 to 5 blood samples were taken, at an interval of approximately 1 year, from 51 Standardbred horses, age 2 weeks-8 years, for a total of 128 observations. The horses could be divided into low (LT) and high (HT) lactate transport activity groups. Age significantly affected (P<0.05) MCT activity such that activity was highest in foals, reached a nadir at 2-3 years, and tended to inc...
Influence of draw reins on ground reaction forces at the trot. According to riding texts, draw reins are supposed to support increased collection. This has not been measured objectively. Therefore, the objective of this study was to determine whether a horse ridden with draw reins would relatively increase weightbearing of the hindquarters while worked with the draw reins compared to a normal rein. Ground reaction forces were measured in 8 horses at the slow trot over a force plate in 3 different experimental set-ups: 1) riding with only a draw rein (DR); 2) riding with the combination of a normal and a draw rein (NR-DR) and 3) riding with a normal rein (...
Effect of instillation into lung of autologous blood on pulmonary function and tracheobronchial wash cytology. This study aimed at measuring the functional consequences and the pulmonary cytology changes following a simulation of pulmonary haemorrhage. Pulmonary function tests including lobeline-induced hyperventilation, cytology of tracheo-bronchial wash (TBW) and thoracic radiographs were performed before, as well as 1, 7, 14 and 28 days after, the instillation of 300 ml of blood into the lungs of 4 horses deemed free of exercise-induced pulmonary haemorrhage (Group 1). Control data (Group 2) were obtained by instilling the same volume of saline into the lungs of the same horses in a crossover design...
Evaluation of the i-STAT hand-held chemical analyser during treadmill and endurance exercise. This study examined the accuracy and precision of a hand-held, chemical analyser, i-STAT, in measuring selected blood constituents which may be of use in the diagnosis and management of metabolic disorders found in exercising horses. Venous blood samples were taken from 3 Thoroughbred geldings, fit and trained to exercise on a treadmill, both before and after exercise at a speed sufficient to elicit VO2max. The samples were analysed both with the i-STAT and with in-house analysers to compare the values of pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), bicarbon...
Potassium and lactate uptake by noncontracting tissue during strenuous exercise. Efflux of potassium (K+) and lactate (lac-) from active skeletal muscle during high intensity exercise leads to increased plasma [K+] and [lac-] in venous and arterial blood. The exercise-induced increases in these ions in human athletes is ameliorated, in part, by uptake by noncontracting tissue, reflected by an increase in the arteriovenous difference across these tissues from rest to exercise. To test the hypothesis that these ions are taken up by noncontracting tissue in strenuously exercising horses, plasma [K+] and [lac-] were measured in blood samples collected simultaneously from the c...
Comparison between glycerol and ethylene glycol for the cryopreservation of equine spermatozoa: semen quality assessment with standard analyses and with the hypoosmotic swelling test. The aims of this study were to compare glycerol (G) at customary concentrations and ethylene glycol (EG) as cryoprotectants for stallion semen in a skimmed milk (SM) extender, to test different EG concentrations and to compare the results of manual and computerized analysis with the hypoosmotic swelling (HOS) test. Ejaculates from two stallions were collected over 3 weeks (6 ejaculates per stallion), diluted in a SM based extender, divided into 4 fractions, centrifuged and diluted again to a concentration of 100 x 10(6) mL(-1) progressive motile spermatozoa (PMS) in addition with the cryoprote...
Lactate transport in red blood cells by monocarboxylate transporters. The lactate transport activity of red blood cells (RBC) varies widely among different species; in equine RBC, the activity of the main lactate carrier, H+-monocarboxylate co-transporter (MCT), is distributed bimodally. The influence of lactate transport activity is measurable in vivo; after maximal exercise, the RBC lactate concentration in horses with high (HT) lactate transport activity is higher than in those with low (LT) activity. To study the expression of MCT in HT and LT horses, blood samples were taken from 10 horses at rest and after submaximal exercise. Blood and plasma lactate conc...
Effects of fat adaptation on glucose kinetics and substrate oxidation during low-intensity exercise. This study was designed to determine the effects of fat adaptation on carbohydrate and fat oxidation in conditioned horses during low-intensity exercise. Five mature Arabians were studied. The study was conducted as a crossover design with 2 dietary periods, each of 10 week's duration: a) a control (CON) diet, and b) a fat-supplemented (FAT) diet. The total amount of digestible energy (DE) supplied by the fat in the CON and FAT diets was 7% and 29%, respectively. During each period, the horses completed exercise tests at the beginning of the period (Week 0) and after 5 and 10 weeks on the diet...
Early evaluation of dressage ability in different breeds. Dressage is one of the Olympic equestrian sports practiced in several countries using different horse breeds. Specific characteristics of the walk, trot and canter are required for dressage. It has been assumed that some of these traits could be selected for genetically and contribute to dressage performance. The purpose of this study was to compare the walk, trot and conformation characteristics in young horses of different breeds used for dressage. A total of 142 horses age 3 years were classified into 3 groups of breeds (German, French and Spanish saddle horses) and tested using the same pr...
Effect of an endurance race on muscle amino acids, pro- and macroglycogen and triglycerides. Glycogenolysis and lipolysis are essential for energy production in muscle during prolonged exercise but less is known about the role of amino acid metabolism. The aim was to study the effect of an endurance race on pro- and macroglycogen, triglycerides and amino acid concentrations in muscle and on selected blood parameters, especially the amino acid response in the blood during the recovery phase. Seven endurance-trained horses completed a race covering 100-120 km. Blood samples were collected one day before the race, after the finish and 1 and 8 days after the race. Needle biopsy specimens ...
Evaluation of three ancillary treatments in the management of equine grass sickness. Brotizolam, acetylcysteine and aloe vera gel were evaluated as ancillary treatments for 29 cases of equine grass sickness. None of the treatments had any significant beneficial effect on the survival of the horses. However, 11 of 13 horses with mild chronic grass sickness survived solely with intensive nursing care.
Three-dimensional kinematics of the tarsal joint at the trot. The tarsal joint is a common site of injury for many sport horses. Understanding the biomechanics of this complex joint begins with developing a clear picture of the kinematics during normal locomotion. This study describes the 3D kinematics of the tarsal joint by measuring the motion of the tibia and third metatarsus in 4 sound Quarter Horses with targets attached directly to the bones via steel pins. The objective was to determine if the tarsus had significant motion outside the tarsocrural joint. Two Steinmann pins were inserted into the lateral side of the right hindlimb and marker triads ...
Plasma lactate and uric acid responses to racing in pacing Standardbreds and relationships with performance. Relationships between racing performance and plasma lactate and uric acid concentrations after racing were investigated in pacing Standardbred racehorses. The study was undertaken in order to better understand factors that limit racing performance. Twenty horses were tested after races of 1760 m and 28 horses after races over 2160 m. Blood samples were taken 30-60 min before and 8 and 30 min after a race. There were no significant differences between the race distances for prerace and 8 min postrace plasma lactates. Significant low correlations were obtained for plasma lactate concentration 8 ...
Effect of short-term exercise training on insulin sensitivity in obese and lean mares. Twelve untrained aged mares were used to determine whether 7 days of light exercise improved peripheral tissue insulin sensitivity. Mares were divided into obese-exercised (n = 3), obese-sedentary (n = 3), lean-exercised (n = 3) and lean-sedentary (n = 3) groups. The exercised groups were worked at a trot to a heart rate (HR) of not more than 140 beats/min for 30 min in a round pen. Each group was subjected to 3 euglycaemic hyperinsulinaemic clamps: prior to exercise (P), 24 h following the seventh exercise training session (E) and 9 days postexercise training (PE). Prior to exercise training,...
