What are they?

Enteroliths are stone-like formation that develop in a horse’s colon and have the potential to cause colic and potentially an obstruction.

How do they form?

Enteroliths form in an alkaline pH environment like that of the equine large colon and has high levels of magnesium, calcium, phosphorus, sodium and potassium. This is a common finding in horses that are fed an exclusively alfalfa based diet. They often form around a piece of gravel, sand, hair or other small foreign objects. Arabians, Morgans, American Miniature, and Saddlebred horses are particularly pre-disposed.

​​​​​​​How do I prevent them?

The main risk factor for enterolith formation is an alfalfa hay diet. It is advisable to try transitioning to a mixed hay diet, rather than alfalfa alone (up to about 30% of the diet may be fed as alfalfa). Taking measures to prevent horses from eating dirt or gravel, placing mats or shavings down in areas where they are fed may help.