Timing Of Starch Feeds Relative To Exercise

At Saracen Horse Feeds we often get asked the question, “When should I feed my horse before exercise or a competition?”

The answer depends on what the horse will be eating and how it will be exercised. Research has shown that a cereal based meal (either with or without hay) fed two hours prior to a period of exercise such as endurance and the speed phase of a three-day event, decreased free fatty acid availability and plasma glucose concentration (Pagan and Harris, 1999).

Moreover, cereal based meals fed three hours prior to exercise also decreased plasma glucose and free fatty acid concentrations, which serve as fuels for the horse (Lawrence et al., 1993).

Limiting two necessary fuels for energy will compromise performance, particularly higher intensity performance at the intermediate and elite levels. Additionally, feeding a cereal based meal two hours prior to exercise, and ad libitum hay, resulted in decreased plasma volume and elevated body weights, making the blood thicker and the horses heavier (Pagan and Harris, 1999). This also could be a detriment to achieving peak performance.

Feeding hay alone did not decrease free fatty acid and glucose availability; therefore, performance will not be limited by the decreased fuels as seen with cereal meals prior to exercise. However, feeding hay alone may produce a decrease in plasma volume and elevated body weights, similar to the cereal-based meals. Feeding hay in small amounts on a frequent basis may reduce the consequences of withholding hay to stabled horses (such as gastric ulcers) whilst still supporting performance.

Not only does a cereal based meal affect fuel availability, but it may also affect heart rate. Higher heart rates during the first five minutes of exercise were found in ponies that had consumed cereal meals at 0.7% of their body weight prior to exercise (Duren et al., 1992). Similar results were also seen in horses that consumed cereal meals two hours prior to exercise. However, horses that were fed less than 0.5% of their body weight in cereal-based feeds did not have higher heart rates during exercise (Lawrence et al., 1995).

Higher heart rates at a given speed could have an undesirable effect on performance, as the heart would be working at a faster rate than it should. In essence, the conditioning put into a horse to decrease his heart rate at a given speed would be undone. Even though research results are inconclusive, the potential for increased heart rate should be avoided by giving the horse forage only (ad libitum or up to 1% of body weight) prior to competition and feeding the last cereal and starch-based feed no less than up to 4 hours prior to exercise.