Alterations in plasma corticosteroids, insulin and selected metabolites in horses used in endurance rides.

The research studies the impact of extended exercise on the plasma concentrations of various substances in horses participating in a 160 km endurance ride, and attempts to find any significant differences in these concentrations between horses that completed the course and those that did not.

Objective of the Study

• The study examined the changes in plasma concentrations of corticosteroids, insulin, glucose, lactate and beta-hydroxybutrate in horses during prolonged exercise, specifically a 160 km endurance ride.
• The research aimed to determine whether these parameters could indicate significant differences between horses which completed the endurance ride and those which could not.

Methodology of the Research

• The starting number of horses in the study is 53.
• Throughout the endurance course, the horses’ plasma concentrations of corticosteroids, insulin, glucose, lactate and beta-hydroxybutyrate were monitored and recorded to study the effects of prolonged exercise.

Findings of the Study

• Plasma corticosteroids were observed to increase while glucose and insulin showed decreases during the exercise.
• The plasma lactate or beta-hydroxybutyrate levels, however, saw little to no change throughout the exercise.
• There were no consistent significant differences found in these parameters between horses which managed to complete the 160 km endurance ride and those which failed to do so.

Implications of the Research

• The research suggests that plasma concentrations of these substances are affected during prolonged exercise in horses, except for lactate and beta-hydroxybutyrate which showed little change.
• However, these physiological changes do not reliably indicate a horse’s ability to complete a long-distance endurance course, suggesting that other factors need to be considered in understanding and predicting equine endurance performance.