The effects of timing and amount of forage and grain on exercise response in thoroughbred horses.

The research evaluates how the timing and components of a horse’s diet (hay and grain) can affect its blood glucose response, hydration, and performance levels during exercise. The results suggest that providing horses with small amounts of hay before exercise could be beneficial, but the grain should be avoided to maintain optimal performance and health.

Experiment Overview

• The study comprised three different experiments, each designed to gauge how different feeding patterns influence the physiological responses of horses under exercise conditions.
• Experiment 1 focused on the effect of feeding hay at three different times relative to a grain meal.
• Experiment 2 observed whether feeding grain with or without hay before a competition exercise test (CET) would impact substrate utilization during exercise.
• Experiment 3 evaluated the effects of feeding only forage but no grain prior to a CET on horses’ performance and substrate utilization.

Key Findings

• The first experiment showed that the timing of hay feeding affected the glycaemic response, plasma protein, and water intake post grain feeding. This indicates that the timing of forage feeding can impact a horse’s metabolic activities.
• In the second experiment, feeding grain to horses before exercise reduced the availability of free fatty acids, increased blood glucose usage during activity, and led to higher lactate production and heart rates. The presence of hay with grain or alone before exercise also caused a reduction in plasma volume. These findings suggest that feeding grain prior to physical exertion may affect the horse’s exercise performance.
• The third experiment showed that feeding horses only forage (hay), but no grain, before exercise did not negatively impact their performance. This implies that horses can be effectively energized for exercise through forage alone.

Conclusion

• The study concluded that to maintain optimal performance and health, it would be beneficial to withhold grains from a horse’s diet before exercise. However, small quantities of hay should be provided to ensure proper gastrointestinal tract function.