Colic is one of the worst threats facing a horse owner , yet it is not a diagnosis, but rather an indication of abdominal pain. This pain may be caused by the kidneys, the bladder, the liver, or the intestine. Intestinal colic causes range from a mild gas colic or an impaction that responds to medical treatment to a bowel displacement or intestinal obstruction requiring surgical treatment. One type of colic requiring surgical treatment is caused by enteroliths (stones in the intestine). Diagnosis of an enterolith can usually only be made during surgery since the stones cannot be palpated from the rectum and are not always visible on an abdominal radiograph.

An enterolith is a concretion of minerals, mostly Ammonium-Magnesium-Phosphate, forming around a nidus such as a piece of metal or wood. The exterior surface may be rough or smooth and there can be one or multiple stones found in an area. The enterolith causes a partial or total obstruction of the right dorsal colon, the transverse colon, or the proximal small colon with the degree of colic signs depending on the amount of obstruction. Although most commonly seen in California and Texas, Willamette Valley Equine has had two surgical enterolith cases this year with successful post operative recovery.