ABSTRACT
The association between feeding practices and equine gastrointestinal dysfunction has been demonstrated by several epidemiologic studies.1-6 Thus, it is interesting to review the effects of common feeding practices on equine gastrointestinal physiology.
Feeding Grain To provide enough energy and protein to maximize performance (growth, reproduction, speed, and strength), grain is frequently added to horses’ diets. Ingestion of grain has long been recognized as a potential cause of gastrointestinal dysfunction in horses,7 however, and has been confirmed by recent epidemiologic studies.4-6 Grains are rich in hydrolyzable nutrients8 and may cause digestive problems in a gastrointestinal tract that evolved to digest plant material having a higher fiber content.9 Hydrolyzable nutrients are digested by enzymes secreted by the salivary glands, stomach, pancreas, and small intestine. When large amounts of hydrolyzable nutrients are ingested (e.g., as occurs with grain meals), the digestive capacity of the gastrointestinal tract preceding the cecum may be overloaded, and large amounts of hydrolyzable nutrients can become available for fermentation in the large intestine.10,11
