The wall of the intestine is stretched excessively by gas, fluid, or partially digested food.
There is tension on the tissue that supports the intestines (mesentery) due to the intestine moving out of its normal position.
There is inflammation or ulceration in the stomach or intestine.
Part of the intestine has reduced blood flow, most often as a result of passing through a hernia or severe twisting of the intestine.
Inflammation develops which involves either the entire intestinal wall or the covering of the intestine.
The intestine and/or its blood supply have become obstructed by feed, sand (if horses are fed on the ground where soil is sandy), parasites, or other foreign material.
Enteroliths (rock-like concretions of material) have developed in the large intestine.