The stomach of an average horse is comparatively small. It only has a capacity of about 3-4 gallons. The junction of the equine esophagus and stomach does not allow pressurized gas, fluid, or feed to escape.

A horse’s stomach ruptures when pressure inside becomes great enough to burst the stomach wall. This usually occurs in cases of small intestinal or stomach obstruction or overfilling. Horses with stomach overfilling and stretching exhibit signs of severe abdominal pain. If this is not promptly resolved with veterinary treatment, it worsens, and rupture occurs.

When possible, vets reduce pressure within the stomach by passing a nasogastric tube. This is not always as easy and effective as it sounds. In some cases, solid feed is very difficult to remove with a tube.

Regardless, horses suffering from this problem usually have a history of colic that lead up to this fatal event. Prompt veterinary attention is the way to avoid this problem.

Other segments of intestine can rupture as well, usually as a consequence of intestinal wall damage, and excessive pressure from obstruction. The result is the same, widespread contamination and infection of the abdomen.