Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Exercise
Exercise in horses encompasses the physical activities that horses engage in, either through natural behaviors or structured training programs. These activities impact a horse's musculoskeletal, cardiovascular, and respiratory systems, influencing overall health and performance. Exercise can vary in intensity, duration, and frequency, and its effects are studied to understand conditioning, endurance, and recovery processes in equines. Research in this field often focuses on the physiological adaptations to different types of exercise, the prevention of exercise-related injuries, and the optimization of training regimens for various equestrian disciplines. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, biomechanical, and health-related aspects of exercise in horses.
The synchronization of ventilation and locomotion in horses (Equus caballus). Ciné film and synchronized records of respiratory flow were obtained from Thoroughbred racehorses cantering on a treadmill at speeds of 9 and 11 m s-1. Horses and some other galloping and hopping mammals link their breathing and locomotion, taking exactly one breath per stride. Three theoretical mechanisms by which the movements of locomotion might drive ventilation are considered. (i) Flexion of the lumbosacral joint and the resulting forward sweep of the pelvis pushes the viscera against the diaphragm. However, back flexion lags behind ventilation at 11 m s-1 and could not exclusively drive...
Influence of furosemide on hemodynamic responses during exercise in horses. Four hours prior to exercise on a high-speed treadmill, 4 dosages of furosemide (0.25, 0.50, 1.0, and 2.0 mg/kg of body weight) and a control treatment (10 ml of 0.9% NaCl) were administered IV to 6 horses. Carotid arterial pressure (CAP), pulmonary arterial pressure (PAP), and heart rate were not different in resting horses before and 4 hours after furosemide administration. Furosemide at dosage of 2 mg/kg reduced resting right atrial pressure (RAP) 4 hours after furosemide injection. During exercise, increases in treadmill speed were associated with increases in RAP, CAP, PAP, and heart rate...
Ultrasound speed in the metacarpal cortex–a survey of 347 thoroughbreds in training. Transmission ultrasound speed was determined in the third metacarpal bone of 347 Thoroughbred racehorses in training. In addition to direct measurement of apparent ultrasound speed and lateral bone diameter, several derived parameters were estimated (cortical ultrasound speed, corticomedullary ratio and cortical cross-sectional area). Multiple regression equations were developed for each ultrasound measurement using the explanatory variables: sex, age, duration and intensity of training, preparation number and previous shin soreness. The horses (114 females, 82 entire males and 151 geldings ra...
Pulmonary artery and aortic pressure changes during high intensity treadmill exercise in the horse: effect of frusemide and phentolamine. Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in ...
Plasma potassium and lactate concentrations in thoroughbred horses during exercise of varying intensity. To investigate the effect of moderate to high intensity exercise of up to 6 min duration on plasma potassium and lactate concentrations, 6 Thoroughbred horses were studied using a treadmill at a 5 degree incline. Each test consisted of an 8-min standardised warm-up followed by an exercise bout at 8, 9, 10 or 12 m/sec. The horses were galloped at each speed for up to a maximum of 6 min or until signs of fatigue were present. The horses were then walked at 0 degree incline. Carotid arterial blood samples were taken during and after the exercise. At 8, 9 and 10 m/sec there was a general pattern o...
Determination of sensitivity to metocurine in exercised horses. On the basis of results in dogs, conditioning exercise may increase sensitivity to nondepolarizing muscle relaxants. Five Thoroughbreds were exercised/conditioned 3 times weekly on a treadmill for 8 months. Increasing maximal rate of O2 consumption verified that the horses were responding to exercise conditioning. Six nonexercised Thoroughbreds served as the control group. Studies were done with horses under general anesthesia by use of halothane during partial paralysis by a brief constant-rate infusion with the muscle relaxant, metocurine iodide. Quantification of degree of paralysis of the ...
Skeletal muscle fiber size in untrained and endurance-trained horses. The mean area and minimal diameter of 3 histochemically determined myofiber types (1, 2A, and 2B; myosin ATPase in acid buffer) were calculated in middle gluteal muscle biopsy specimens from 62 stallions, 47 Andalusians and 15 Arabians, ranging in age from 6 to 12 years. Fourteen Andalusians and 7 Arabians were untrained, and the remainder were actively endurance-trained. The 6-month training schedules involved walking, slow trotting, and cantering. Fourteen Andalusians were moderately endurance-trained, whereas the other 19 Andalusians and 8 Arabians were strongly endurance-trained. Significa...
Growth hormone in mares and stallions: pulsatile secretion, response to growth hormone-releasing hormone, and effects of exercise, sexual stimulation, and pharmacological agents. Short-term patterns of growth hormone (GH) secretion and factors affecting it were studied in mares and stallions. In Exp. 1, hourly blood samples were collected from three mares and three stallions in summer and winter. Although GH concentrations varied in a pulsatile manner in all horses, there was no effect of sex or season (P greater than .1) on plasma GH concentrations and no indication of a diurnal pattern of GH secretion. In Exp. 2, 10-min blood samples were drawn for 8 h from 12 mares; after 6 h, porcine GH-releasing hormone (GHRH) was administered i.v. at 0, 45, 90, or 180 micrograms/...
Ejaculatory failure associated with aortic-iliac thrombosis in two stallions. Two mature breeding stallions were evaluated because of specific ejaculatory dysfunction, and each was found to have aortic-iliac thrombosis occluding 60 to 70% of the aortic lumen. In each case, the stallion had strong libido, normal mounting, and vigorous initial thrusting. With continued exertion, thrusting became weak and dismount was awkward. Treatment aimed at maximizing sexual arousal before mounting and reducing hind limb pain and exertion during breeding allowed these stallions to continue breeding. A program of gradually increasing daily exercise also was associated with improved bre...
Respiratory muscle perfusion in ponies during prolonged submaximal exercise in thermoneutral environment. Distribution of blood flow among various respiratory muscles was examined in 8 healthy ponies during submaximal exercise lasting 30 minutes, using radionuclide labeled 15-microns diameter microspheres injected into the left ventricle. From the resting values (40 +/- 2 beats/min; 37.3 +/- 0.2 C), heart rate and pulmonary arterial blood temperature increased significantly at 5 (152 +/- 8 beats/min; 38.6 +/- 0.2 C), 15 (169 +/- 6 beats/min; 39.8 +/- 0.2 C), and 26 (186 +/- 8 beats/min; 40.8 +/- 0.2 C) minutes of exertion, and the ponies sweated profusely. Mean aortic pressure also increased progr...
Metabolic response of horses to a high soluble carbohydrate diet: effects of low-intensity submaximal exercise and sodium bicarbonate supplementation. Four mares fed a low fiber, high soluble carbohydrate diet were used in a crossover design to evaluate the effects of dietary sodium bicarbonate (NaHCO3) supplementation during daily low-intensity submaximal working conditions. Mares were fed the diet at 1.7 times the maintenance energy requirement for mature horses at work. The horses tolerated the diet well and had no clinical abnormalities. Resting venous blood bicarbonate (HCO3), standard HCO3, and base excess (BE) concentrations significantly (P less than 0.05) increased with NaHCO3 supplementation, but no significant changes in resting v...
Effects of induced alkalosis on performance in thoroughbreds during a 1,600-m race. There is considerable debate regarding the ergogenic effects of sodium bicarbonate (NaHCO3) on racing performance in horses. Anecdotal evidence suggests that NaHCO3 improves performance by increasing the buffering capacity of the blood and delaying the onset of hydrogen ion-induced fatigue. In a cross-over study, 16 Thoroughbred racehorses were given an aqueous solution of NaHCO3 (0.4 g/kg in 1 litre H2O) or a control treatment (1 litre H2O) before a 1600-m race. Treatments were administered 3 h before the race, which was the time to peak buffering capacity (2.5-3.0 h) determined in a separate...
Ultrastructural changes in skeletal muscle after fatiguing exercise. Thoroughbred horses were exercised to fatigue at 40, 85, and 100% of their maximal oxygen consumption (VO2max) on a treadmill and completed a 1,600-m gallop on a track to identify the effect of exercise of various durations and intensities on the ultrastructure of mitochondria and sarcoplasmic reticulum (SR) from the middle gluteal muscle. The percentage of the total area occupied by mitochondria and SR increased in electron micrographs of muscle samples collected at the termination of exercise and at 30 and 60 min of recovery compared with those collected before exercise. Mitochondrial area i...
Effect of competition on performance of thoroughbred racehorses. The effect of competition and the influence of age and sex on performance were examined in a study of 18 Thoroughbred racehorses. The horses performed two solo and two competitive runs at 1,200 and 1,600 m for a total of eight runs. No group ran faster during competition, which may have been a reflection of the quality of horses used for this study and their susceptibility to stress-induced impairment of performance. Males showed no significant difference between competitive and solo run times, whereas females were consistently slower during competition. Males ran significantly faster than fem...
Free fatty acids in exercising Arabian horses fed two common diets. Four Arabian geldings were used in a randomized, repeated measure design to study the effect of two different diets on plasma free fatty acids at rest and during exercise. On each of four sampling days, two horses were fed one of two isoenergetic diets, either 100% corn or 100% alfalfa, at 22% of their estimated daily energy requirement. Two hours after the consumption of the diet, each horse participated in a submaximal standard exercise test consisting of three consecutive 10-min runs of increasing intensity at heart rates of 132, 140 and 147 beats/min, respectively. There were no significan...
Mathematical modelling of post-exercise heart rate recovery in ponies. Using a recently developed nonlinear algorithm which identifies reference points on left ventricular pressure waveforms and other waveforms, we analyzed heart rate recovery in ponies after strenuous treadmill exercise. Each pony performed exercise tests with and without premedication with atropine methyl nitrate. Resting and exercise heart rates were 54 +/- 3 and 209 +/- 6 beats/min, respectively, without premedication and 85 +/- 8 and 212 +/- 5 beats/min, respectively, following atropine premedication. Post-exercise heart rate recovery without premedication was best described by a biexponenti...
Total carnitine content of the middle gluteal muscle of thoroughbred horses: normal values, variability and effect of acute exercise. There was no detectable loss of total carnitine associated with intense exercise from the middle gluteal muscle of Thoroughbred horses. Measurements made on a single biopsy obtained during the course of a normal training and exercise programme may, therefore, be considered representative of the normal content at rest. The variability in total carnitine content within the normal muscle biopsy area amounted to 13.2 per cent of the normal mean content. Approximately 50 per cent of this variability could be attributed to covariation with citrate synthase, to which it was highly significantly corre...
[Physical performance–a comparison between horses and men]. During heavy exercise horses can increase oxygen uptake compared to resting conditions considerably more than man. Processes involved like respiration, heart size, cardiac output, oxygen transport capacity of the blood and oxygen release in the capillaries are discussed. Besides these advantages in the aerobic metabolism conditions for the anaerobic metabolism are also more advantageous in horses than in man. The portion of fast contracting muscle fibers with little fatigue-resistance and also some of the enzymes required for the anaerobic metabolism are higher in horses.
Adenine nucleotide degradation in the thoroughbred horse with increasing exercise duration. Adenine nucleotide (AN) degradation has been shown to occur during intense exercise in the horse and in man, at or close to the point of fatigue. The aim of the study was to compare the concentrations of muscle inosine 5'-monophosphate (IMP) and plasma ammonia (NH3) during intense exercise with the concentrations of muscle and blood lactate. Seven trained thoroughbred horses were used in the study. Each exercised on a treadmill for periods of between 30 s and 150 s, at 11 and/or 12 m.s-1. Blood and muscle samples were taken and analysed for lactate and NH3 and adenosine 5'-triphosphate (ATP), ...
Effects of treadmill exercise on cortical bone in the third metacarpus of young horses. The effects of exercise and relative inactivity on cortical bone were compared in young horses. Two groups were used; one was given a 14-week programme of exercise (n = 6) and the other kept as unexercised controls (n = 6). The first nine weeks of exercise involved trotting and cantering (2 to 4 km d-1 at speeds up to 12 m s-1) on a treadmill set at an incline of 3 degrees. Over the next five weeks the horses were trained at near maximal speeds (that is, up to 14.5 m s-1) with no incline of the treadmill. At the end of the programme marked differences in cortical porosity and distribution of s...
Exercise-induced pulmonary hemorrhage in horses with experimentally induced allergic lung disease. The lungs of sensitized horses were exposed to aerosolized ovalbumin. Some horses (n = 4) were given ovalbumin in 1 lung only, whereas in others (n = 7), ovalbumin or vehicle were inoculated in the cranial, ventral, and caudal regions of the caudal lung lobe. Horses were exercised 5 hours after ovalbumin exposure. Immediately before exercise, endoscopy failed to reveal any abnormality. After exercise, endoscopic examination of horses subjected to unilateral ovalbumin exposure revealed extensive blood in airways leading to the exposed lung in all horses. Blood was not observed in the airways le...
Respiratory muscle recruitment in awake ponies during exercise and CO2 inhalation. We measured respiratory muscle electromyograms (EMG), inspiratory (I) and expiratory (E) airflow patterns and functional residual capacity (FRC) in six ponies at rest, during treadmill walking at 1.8 mph-5, 10, and 15% grades, and during 2, 4, and 6% CO2 inhalation. There were several similarities in the responses to exercise and CO2 inhalation. The shapes of the I and E flow patterns were not changed appreciably from the respective control patterns during either condition. Mean diaphragm EMG increased from control (P less than 0.05) at 1.8 mph-10 and 15% grades, and during 4 and 6% inhalation...
Exercise-induced phospholipid degradation in the equine skeletal muscle and erythrocytes. To understand the pathogenesis of equine exercise-induced myopathies and hemolysis, changes of phospholipid peroxidation products in the equine middle gluteal muscle and erythrocytes following the high-speed treadmill exercise were studied. In the skeletal muscle, the peroxidized phosphatidylethanolamine (PE) were increased at 24 hours after the exercise. The malondialdehydes (MDAs) were also increased as the protein-bound MDAs following exercise. In the erythrocytes, the peroxidized PE were significantly decreased at 24 hours after the exercise. The protein-bound MDAs were significantly incre...
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.
Plasma beta-endorphin and adrenocorticotrophin in young horses in training. A controlled period of submaximal exercise on a treadmill was used as a standardised stress test in 6 young horses to monitor the effects of training. Circulating plasma concentrations of immunoreactive beta-endorphin (IR beta-EP) were measured before, during and after the exercise period. The stress test was conducted on 3 occasions during an intensive training program lasting 14 weeks. In week 3 a marked increase in plasma IR beta-EP (P = 0.003) was demonstrated as a result of training, but by the last exercise test performed in week 9 no significant increase in plasma IR beta-EP concentrati...
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...
Value of standardised exercise tests and blood biochemistry in the selection and training of breeding stallions. Stallions selected by the Royal Dutch Warmblood Society were submitted to a standardised lungeing test at the beginning and at the end of a 100-day test of performance and ability. The heart rate, haematology and biochemistry values obtained in the first lungeing test showed no significant differences between the 15 stallions which were rejected by the Royal Dutch Warmblood Society during the first month of the 100-day test, the 15 stallions rejected during the last month and the 11 stallions which were approved for registration in the studbook. The 26 stallions submitted to the second lungein...
Common horse sense. This research article corrects a common misconception about the energy metabolism in horses during short sprinting and long-distance running events, emphasizing that short sprints are primarily powered by anaerobic activity, […]
Metabolic responses to ammonium acetate infusion in exercising horses. The relationship between elevated plasma ammonia (NH3) levels, fatigue development and muscle metabolism were examined in horses during a submaximal fatigue test. Eight Quarter Horse mares were intravenously infused prior to exercise with either sodium acetate (control) or ammonium acetate (AMINF), and exercised to fatigue on an 11% grade treadmill, carrying 27 kg of lead. Time to fatigue was not different (P greater than 0.05) between groups. Intramuscular NH3 and lactate increased (P less than 0.001) during exercise; however, the treatment did not (P greater than 0.05) affect either. A treat...
Plasma concentrations of cortisol, prolactin, luteinizing hormone, and follicle-stimulating hormone in stallions after physical exercise and injection of secretagogue before and after sulpiride treatment in winter. Ten lighthorse stallions were used to determine 1) whether prolactin (PRL) and cortisol responses previously observed after acute exercise in summer would occur in winter when PRL secretion is normally low, 2) whether subsequent treatment with a dopamine receptor antagonist, sulpiride, for 14 d would increase PRL secretion and response to thyrotropin-releasing hormone (TRH) and exercise, and 3) whether secretion of LH, FSH, and cortisol would be affected by sulpiride treatment. On January 11, blood samples were drawn from all stallions before and after a 5-min period of strenuous running. On J...
