Consumption of large amounts of sand, which then accumulates in the large intestine, can produce diarrhea, weight loss, or colic. Sand is ingested when horses or foals are kept on sandy pasture or are fed hay or grain in a sandy area (paddock, stall, or pasture). Some horses or foals preferentially eat dirt and sand if it is in their environment. A diagnosis is based on history of a sandy environment, the presence of sand in the feces, “sand sounds” on auscultation of the ventral abdomen, and (if available) abdominal radiographs that reveal the presence of sand in the large colon. Treatment involves use of a hemicellulose product (psyllium seed hull) administered via nasogastric tube or added to the grain daily. Diarrhea generally resolves within 2–3 days of initiation of treatment. Generally, 3–4 wk of treatment is necessary to remove most of the sand and may need to be repeated if the horse or foal is not removed from the source of sand. Preventive psyllium treatment (daily for 1 wk each month) has been used where sand enterocolitis is common. Several psyllium products are on the market; many horses prefer the pelleted over the powdered form. (Also see Cecum and Large Intestine Cecum and Large Intestine The most common cause of gastric dilatation in horses is excessive gas or intestinal obstruction. Gastric dilatation may be associated with overeating fermentable feedstuffs such as grains,... read more 
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