How Amylase Supports Equine Digestion
Why Horses Struggle With Starch
Horses are hindgut fermenters. Unlike pigs or dogs, they were never designed to process large amounts of starch in the small intestine. Research has documented that horses have low concentrations of alpha-amylase throughout the gastrointestinal tract compared to other monogastric species. This means a significant portion of dietary starch can pass through the small intestine undigested.
What Happens to Undigested Starch
When starch escapes the small intestine, it enters the cecum and large colon. Here, bacteria rapidly ferment the starch, producing lactic acid rather than the beneficial volatile fatty acids (VFAs) that come from fibre fermentation. This lactic acid lowers the pH of the hindgut, creating an acidic environment that disrupts the delicate microbial balance.
The Role of Supplemental Amylase
Supplemental amylase works in the small intestine, where starch digestion is meant to occur. By increasing the amylase available in the foregut, more starch is broken down into simple sugars before it reaches the hindgut. This reduces the substrate available for rapid bacterial fermentation and helps maintain a stable hindgut pH.
Practical Implications
For performance horses receiving grain-based feeds, the gap between starch intake and enzymatic capacity is particularly relevant. A racehorse or sport horse consuming 4 to 6 kg of grain per day is asking its small intestine to process far more starch than its natural enzyme levels can handle. Supporting this process with exogenous amylase is a logical nutritional strategy.