Effect of ration and exercise on plasma creatine kinase activity and lactate concentration in Thoroughbred horses with recurrent exertional rhabdomyolysis.

This research article explores how different diets and exercise impact blood levels of creatine kinase (CK) and lactic acid in Thoroughbred horses that commonly suffer muscle damage (RER). It found that high-grain diets seemed to increase CK activity, and that horses exercising at slower speeds had higher increases in CK than those going at full speed.

Research Purpose and Methodology

• The primary objective of this study is to understand how three different diets (fat, low grain, and high grain) affect the blood levels of creatine kinase and lactic acid in Thoroughbred horses, which are prone to recurring muscle damage or rhabdomyolysis (RER).
• The diets were designed either to meet (low-grain and fat diets) or surpass (high-grain diet) the horses’ daily caloric needs.
• Five horses with RER and three horses without the condition (used here as control subjects) were fed each of these diets in a crossover research design. This means each horse tried every diet for three weeks at a time.
• These horses were exercised on a treadmill regularly over the weekdays, at varying speeds depending on the day.
• Plasma CK activity and lactic acid levels were measured before and after exercise.

Research Findings

• Thoroughbred horses with RER displayed greater CK activity and an increase in CK activity four hours post-exercise when fed the high-grain diet compared to the low-grain option.
• Those horses with RER that exercised at trot or canter speeds showed a more significant increase in CK activity than those exercised at a gallop pace.
• The study revealed similar lactic acid levels post-exercise in both non-affected control horses and horses with RER.
• Interestingly, the researchers found no correlation between lactic acid concentration and CK activity in horses with RER.

Conclusions

• The study concluded that high-grain diets, which exceed daily energy needs, may exacerbate instances of RER in Thoroughbred horses. As such, diet could be an important factor in RER management.