Normal intestine undergoes specialized movement called peristalsis (normal motility). Its purpose is to propel feed along the length of the intestine and mix it with secretions, which is a critical part of digestion and absorption of nutrients.

Ileus is lack of intestinal movement or motility. It can result from a variety of causes, including inflammation and trauma from abdominal surgery (post-operative ileus). The word "ileus" implies that we don't necessarily know the underlying cause.

In the horse, the most common segment of intestine affected by post-operative ileus is the small intestine.

Treatment involves correction of any underlying conditions, pain relief, and in some cases, the use of drugs that increase intestinal motility.