We don't know why. It may have something to do with the ability of an individual's intestinal motility to keep things moving along. Or, it may be that one individual tends to pick up more sand than another. While age is not a factor, weanlings, yearlings, and sometimes nursing foals are more inclined to eat sand preferentially, points out Terry Swanson, DVM, CEO of Littleton Large Animal Clinic in Colorado and a former president of the American Association of Equine Practitioners. Typically, the horse suffers from inappetence and abdominal pain.
Diagnosis is based on tests, clinical signs, and observation of the environment.
We look for that when trying to establish a diagnosis. Stool samples are checked for sand. If sand is present, it will settle out first because it is heavier. Take caution, however, for sand can be present in a normal horse's feces as well. Abnormal abdominal sounds might point to sand colic, says Dee.