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Topic:Physiology
The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
Enzyme-linked immunosorbent assay, using staphylococcal protein A for detecting virus antibodies. A modification of the indirect enzyme-linked immunosorbent assay (ELISA) was developed which used staphylococcal protein A linked to horseradish peroxidase. Virus antibodies in equine, bovine, porcine, feline, canine, lagomorphic (rabbit), and human sera were detected, using the indirect ELISA in which the antiglobulin enzyme conjugate was replaced by protein A linked to horseradish peroxidase. Results of the ELISA were compared with the results of the serum-virus neutralization test. The application of the test in laboratories performing serologic assays with sera from diverse animal species ...
Purification and characterization of donkey chorionic gonadotrophin. Serum of the pregnant donkey, like that of the mare, contains a gonadotrophin of chorionic origin. The chorionic gonaditrophin of the donkey (dCG) has been isolated in purified form from the serum of pregnant donkeys using methodology previously employed for the purification of pregnant mare chorionic gonadotrophin (eCG). Unlike eCG, dCG is predominatly an LH in biological tests. In the in-vitro rat Leydig cell assay, dCG was as active as eCG, but in the in-vitro rat seminiferous tubule assay for FSH and in the augmentation assay, dCG was considerably less potent than eCG (1-10%). Specific rat...
Plasma concentration of iditol dehydrogenase (sorbitol dehydrogenase) in ponies treated with aflatoxin B1. Twelve clinically normal Shetland ponies were allocated to one of four treatment groups. Aflatoxin B1 was administered at the dosage level of 2 mg/kg of body weight to group A, 1 mg/kg to group B, and 0.5 mg/kg to group C; a placebo was given to group D (controls). Plasma samples were assayed at 4-hour intervals for iditol dehydrogenase (ID) (sorbitol dehydrogenase) concentrations as an indicator of hepatic damage. One of the ponies in group A died 68 hours after dosing; another pony in group A died 76 hours after dosing. All other animals survived the experiment. The means of peak ID values w...
Clinical approach to determine the contribution of the palmar and palmar metacarpal nerves to the innervation of the equine fetlock joint. To determine the sensory nerve supply of the metacarpophalangeal joint, lameness was induced in eight horses by injecting the joint with a glycerin suspension of glass micropheres. When the medial and lateral palmar nerves were anesthetized in 4 horses, there was noticeable improvement in the gait, but each horse remained lame. When the medial and lateral palmar metacarpal nerves were also anesthetized, 3 of the 4 horses became sound. To confirm the results of local anesthesia, neurectomies were performed on a second group of four horses. The lameness was alleviated only upon resection of both...
[The effect of inbreeding on the manifestations of some physiological traits in the Kladrub Black Horse strain]. Inbreeding was used in the regeneration process in the breeding of the Kladrub Black Horse. Inbreeding rate is realized in practice, as related to the manifestation of the selected characteristics of this unique horse population. The evaluation of the effect of inbreeding on conception rate and fertility did not demonstrate any differences between the group of inbred mares and non-inbred mares. The study was conducted in mares used for breeding for 10 years. The results provide evidence that inbreeding causes no depression in this characteristics in the Kladrub Black Horse which would otherwis...
Ultrasonic treatment of musculoskeletal conditions in the horse, dog and cat. A beam of pulsed ultrasound was used to treat musculoskeletal disorders in 53 horses and 143 dogs and cats. The cases were spread over seven years and 533 separate insonations were made. Doses, which varied according to the lesion, ranged from 0.2 to 3 watts/cm2 for five minutes in each treatment. In 63 per cent of the cases, rapid and complete resolution occurred.
Long distance exercise in the horse: Golden Horseshoe Ride 1978. As part of a study of the metabolic effects of long distance riding the results of biochemical analyses of blood samples taken from horses before, immediately after and one hour after an 80 km ride are reported. The results show that the horses were moderately dehydrated, they were working aerobically using fats as metabolic substrates and blood glucose was reduced. There was no evidence of post exercise ketosis and circulating alanine levels fell. Metabolic hormone levels are reported and are related to the availability of substrates for gluconeogenesis. There was evidence of reduced kidney a...
Studies related to the metabolism of anabolic steroids in the horse: the identification of some 16-oxygenated metabolites of 19-nortestosterone. 1. The metabolism of 19-nor[4-14C]testosterone in a thoroughbred horse has been studied and neutral urinary metabolites obtained after enzyme hydrolysis have been investigated by g.l.c.-mass spectrometry. 2. 3-Hydroxyestran-17-one, 17 alpha- and 17 beta-nortestosterone, estrane-3,17-diol (two isomers), 3,16-dihydroxyestran-17-one (two isomers), 3,17-dihydroxyestran-16-one (two isomers) and estrane-3,16,17-triol were identified in the neutral urinary extracts.
Lameness caused by inflammation in the distal hock. Since horses ridden at a gallop have a high incidence of bone spavin, and harness horses (Standardbred pacers and trotters) have a different
syndrome, they will be discussed separately. Osteoarthritis (bone spavin) apparently is caused by impact and compression on the distal tarsal
bones, which occurs most forcefully at the gallop (canter). Shear stresses, which occur in the joint between these bones, are most severe at the trot
or pace, and probably cause the usual cunean-tarsitis problem in
Standardbreds. Obviously some of each force occurs at each gait.
Changes in blood gas, acid-base and metabolic parameters in horses during three-day event competition. Sixteen horses competing in a three-day event had venous blood samples collected during the speed and endurance test (day 2) to examine changes in blood gas ands acid-base balance, and the concentrations of lactate, pyruvate, beta-hydroxybutyrate, acetoacetate, alpha-ketoglutarate and cortisol. Following the roads and tracks and steeplechase phases there was a significant metabolic and respiratory alkalosis despite a rise in lactate. After completion of the cross country section, although there was a significant decrease in total base, there was no significant change in pH from pre-event value...
Cell morphology and collagen types in equine tendon scar. The histological appearance of cells and tissues in the reparative scar tissue which forms in the equine superficial flexor tendon following partial rupture was compared to that of normal tendon. The repair fibroblasts were found to be larger and more basophilic than the tenocytes of normal tendon, to have large vesicular nuclei and to resemble the 'myofibroblasts' described in scar tissue elsewhere. The cell to matrix ratio in scarred zones of tendon was found to be increased and the concentration of collagen in these areas was less than in normal tendon. However, the scar tissue collagen was...
Skin surface lipids of the horse. Skin surface lipids from the sides of male and female horses (Equus caballus) were collected in acetone and analyzed by thin layer chromatography and gas liquid chromatography. The sole components in both sexes were cholesterol, cholesteryl esters and the lactones of 32-, 32- and 36-carbon omega-hydroxy acids, each including a methyl group in the n-1 position. Most of the lactones were monounsaturated (either n-8 or n-10), but small amounts of saturated and dienoic species were present. A pooled sample of the skin surface lipids contained 14% cholesterol, 38% cholesteryl esters and 48% lactone...
Biochemical characterization of equine herpesvirus type 3-induced deoxythymidine kinase purified from lytically infected horse embryo dermal fibroblasts. Infection of horse KyED cells with equine herpesvirus type 3 (EHV-3) resulted in a sevenfold increase in cytosol deoxythymidine kinase (dTK) activity. The EHV-3 dTK was purified from KyED cytosol dTK by affinity chromatography on deoxythymidine-Sepharose and characterized with respect to its electrophoretic mobility, molecular weight, substrate specificity, phosphate donor specificity, and immunological specificity. The purified EHV-3 dTK migrated in polyacrylamide gels with an Rf of 0.30 and sedimented in glycerol gradients with an S value of 5.13, corresponding to a molecular weight of 83,00...
Comparison of circulatory and respiratory effects of isoflurane and halothane anesthesia in horses. Circulatory and respiratory effects of alveolar concentrations of 1.31, 1.97, and 2.62 vol% of isoflurane in oxygen were studied in eight young, healthy horses during spontaneous and controlled ventilation. These isoflurane concentrations were equivalent, respectively, to 1.0, 1.5, and 2.0 times the minimal alveolar concentration of isoflurane, which prevents movement in horses in response to a standard pain stimulus. Results of the isoflurane studies were compared with similarly derived findings in these same horses during equipotent halothane in oxygen anesthesia. Isoflurane, similar to halo...
Biochemical effects of succinylcholine chloride in mechanically ventilated horses anesthetized with halothane in oxygen. Succinylcholine chloride administered to horses anesthetized with halothane in oxygen and mechanically ventilated, caused slight but statistically insignificant (P less than 0.01) increases in creatine phosphokinase, lactic dehydrogenase, and aspartate aminotransferase activity. The increases in these enzymes have been explained on the basis of muscle damage resulting from succinylcholine chloride induced muscle fasciculations and by hypoperfusion of tissues due to depression of the cardiovascular system caused by general anesthesia. These changes were not clinically apparent based upon the ab...
Cardiorespiratory adjustments to tethered-swimming in the horse. The cardiorespiratory and metabolic responses to various levels of tethered-swimming were evaluated in 5 sedentary horses. Cardiac output (Q) and heart rate (HR) correlated highly (r = 0.89 and 0.94 respectively) with work effort (WE) expressed as kg pulled . kg body wt-1 . 10-2. While swimming, stroke volume (SV) was reduced at the lowest workloads, but increased with increasing WE so that at the highest workloads it had returned to the on-land standing SV. Pressures in the pulmonic as well as on both sides of the systemic circulation were considerably elevated by this form of exercise, altho...
Surgical implantation of cardiovascular devices in the thorax of the horse. A surgical thoracotomy and implantation of an electromagnetic flow probe around the ascending aorta and catheters in the left ventricular (LV) apex of the horse were evaluated. Sixteen operations were done: 4 horses were used for acute experiments, 4 horses died from surgical manipulation, and 8 horses were studied chronically for 18 to 57 days. The electromagnetic flow probe allowed continuous measurement of stroke volume and heart rate. The LV apical catheters, in conjunction with thermal dilution techniques and pressure-sensitive devices, allowed measurement and calculation of mean arterial...
Electromagnetic measurement of cardiac output during exercise in the horse. Aortic root blood flow was measured with an electromagnetic (EM) flow meter in unanesthetized horses during rest and exercise. The cardiac output response to exercise, as determined by the EM technique, was compared with the response reported by others who used indicator dilution techniques with good agreement. The EM method will allow making measurement of cardiovascular responses to exercise in the horse, not obtainable with other techniques.
The effect of trypsin digestion on the structure and iron-donating properties of transferrins from several species. The effect of trypsin digestion on iron-saturated and iron-free (apo) human, rabbit, bovine, pig and horse tranferrins has been studied. Iron-binding fragments were produced only from iron-saturated pig and bovine transferrins although some cleavage of the polypeptide chain occurred in all cases. The apo-transferrins were generally degraded to a greater extent than the corresponding iron-saturated proteins. The ability of the different transferrins to donate iron to rabbit reticulocytes varied in the order rabbit approximately pig greater than human approximately horse greater than bovine. Try...
