Changes in serum muscle enzyme levels associated with training schedules and stage of the oestrous cycle in Thoroughbred racehorses.

The research article investigates the effects of daily training routines and stages of the oestrous cycle on the muscle enzyme levels in racehorses, and how it relates to equine exertional myopathy. The study suggests the existing training schedules could be improved to avoid muscle cell damage that is commonly observed in racehorses after resting days.

Research Methodology

• The study was conducted on 24 Thoroughbred racehorses who were enrolled in a training program at Newmarket over a span of nine months.
• Each horse had blood samples collected twice in a week between 16:00h and 18:00h, to ensure it was at least 6 hours after exercise.
• The samples were carefully analyzed for serum creatine kinase, aspartate aminotransferase, and plasma progestogen concentrations.
• The training followed by all horses was similar and traditional.

Findings of the Study

• The study discovered that there were noticeable variations in serum muscle enzyme concentrations, with changes being more significant in two-year-old fillies than in three-year-old fillies and colts.
• Despite these disparities, the researchers observed no connection between these enzyme level changes and the stage of the oestrous cycle in the horses.
• The research concluded that all horses experience a certain level of muscle cell damage that results in a varying increase in serum creatine kinase levels, post light exercise following a rest day.

Implications of the Study

• The findings suggest that the traditional flat race training may not be the most beneficial or optimal one, causing potential muscle cell damage in the horses.
• For horses showing a propensity for exertional myopathy, a switch in training regimen to include consistent and longer periods of less strenuous exercise could prove to be beneficial.