Question: Is a tendency to colic inherited? I’m looking to breed my mare. I’m considering conformation, temperament and overall health of potential sires. But I’m not sure if I should specifically ask about a colic history. I’ve heard of some stallions that had numerous bouts of colic, and their offspring seemed to as well. Yet I realize many factors go into colic and these things may just be coincidences. Is there any risk in selecting a stallion who has colicked before? My mare never has.

Answer: Colic refers to abdominal pain in horses. Often, the cause of a colic episode is not definitively diagnosed unless something is detectable on ultrasound, rectal palpation or at surgery. I point this out because colic itself—that is, digestive discomfort—has not been shown to be heritable.

Large colon volvulus

The only cause of colic where some degree of heritability has been identified that I know of is large colon volvulus, in which the large colon twists around itself.  Research conducted in Thoroughbred broodmares has shown that this type of colic is “moderately heritable.” In the study that yielded this finding, the researchers compared a common phenotype (presentation) of colic with each horse’s breeding across generations. Their findings suggest that other specific types of colic may also be heritable. But research that could confirm this has not been done or is very limited.

Nephrosplenic entrapment of the large colon

Warmbloods, for example, are more at risk for nephrosplenic entrapment of the large colon. This condition occurs when the ligaments supporting the kidneys and other organs entrap a portion of the large colon. It’s conceivable that this cause of colic is heritable in these breeds. Therefore, depending upon the breed of the stallion, an inherited susceptibility to colic may be a consideration.

You can investigate further by going to a scientific internet search engine such as PubMed and querying “over-representation” of that breed related to colic. You will notice, however, that the only data we have is on an entire breed (Thoroughbred).

A history of colic in a Thoroughbred stallion would not make me concerned about heritability unless you were considering purchasing a related mare for use as a broodmare.

The lack of data on heritability is, in part, because colic is a complex trait. It arises from a many possible causes that include factors such as diet, management, and life history.

Anthony Blikslager, DVM, PhD
North Carolina State University
Raleigh, North Carolina