Year: 1989
Type: dissertation
Abstract: The Thoroughbred racehorse is capable of maintaining speeds of approximately 17 m/s for distances of over a mile. This represents an average speed and the Thoroughbred can reach speeds in excess of 20 m/s over short distances. The present series of studies was undertaken to\ninvestigate further the metabolic response to high-intensity exercise in\nthe Thoroughbred racehorse.\nUnlike man, high-intensity exercise in the horse results in an increase in packed cell volume. This in turn causes acute changes in the colligative properties of blood and plasma. The changes in these properties\nwere investigated and the effect on calculation and distribution of\nmetabolites in blood and muscle was determined. The horse has a high capacity for lactate production compared to man\nand existing methodology for the assessment of muscle buffering capacity in\nbiopsy samples was further developed and investigated. The horse was found\nto have a significantly higher muscle buffering capacity compared with man\nand it was calculated that this could be explained wholly on the basis of\nthe higher muscle carnosine content in the horse. The metabolic response to high-intensity exercise was investigated\nusing several exercise models, including single and multiple field gallops\nand treadmill exercise. A consistent finding was that high-intensity exercise in the Thoroughbred racehorse was nearly always accompanied by a reduction in muscle ATP content. The nature of the ATP decrease was further investigated using a treadmill exercise model. Muscle ATP decrease was\nfound to occur at a particular exercise intensity rather than show a\ngradual decrease with increasing intensity. The intensity at which muscle\nATP content began to decline significantly varied between individual\nhorses, but in each case appeared to coincide with muscle lactate contents\nof approximately 70 mmol/kg dry muscle. The significance of the decline in\nATP is discussed.
Author: David Marlin
Language: English
Subfield: Equine
Field: Veterinary
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W775796689