Running and shipping elevate plasma levels of beta-endorphin-like substance (B-END-LI) in thoroughbred horses.

This study examines the impact of running and shipping on the plasma levels of beta-endorphin-like substances (B-END-LI) in thoroughbred horses. The researchers found that both activities resulted in an increase of B-END-LI levels, which returned to normal after a period of rest.

Research Methodology and Findings

• The goal of the study was to evaluate the changes in plasma levels of beta-endorphin-like substances during different stress-inducing activities in thoroughbred horses. Beta-endorphin is a type of endogenous opioid neuropeptide involved in pain regulation.
• An RIA (Radioimmunoassay) for beta-endorphin was developed specifically for this study to measure the plasma levels of B-END-LI in the horses. The horse’s activities consisted of three exercise speeds for different durations: a 10-minute trot, a 5-minute slow gallop, and a 2-minute fast gallop.
• Blood samples were collected from four horses before, immediately after, and 30 and 60 minutes after the exercise. The study found that trotting moderately increased B-END-LI plasma levels from a base level. These levels decreased to near-basal levels 30 and 60 minutes post-exercise.
• The results from the slow gallop were similar to trotting with a more significant increase in B-END-LI plasma levels. Just like trotting, levels dropped to near-basal 30 and 60 minutes post-exercise.
• The fast gallop triggered the most considerable increase in B-END-LI plasma levels. After peaking five minutes post-fast gallop, the levels then decreased but remained higher than the base level an hour after exercise.
• Additionally, six horses underwent sequential exercises, resulting in an increasing trend in B-END-LI plasma levels from trotting to fast gallop. Following the sequential exercises, the plasma levels gradually returned to almost base level in three hours.
• The study also found that transporting horses in a trailer significantly elevated B-END-LI plasma levels within 30 minutes, which then started declining after 60 minutes.

Conclusion of the Research

• The results demonstrated that both exercise and shipping raised plasma beta-endorphin-like substance levels in thoroughbred horses. Despite the increase, levels typically began to return to normal within 30 minutes for trotting, slow galloping and shipping, while a fast gallop took about an hour for levels to revert back to original levels.
• Understanding these results could be crucial in the management of exercise regimens and transportation practices for horses, potentially informing how to minimize stress and optimize health and performance.