Unlike heart and respiratory rates, abdominal sounds do not punch a specific time clock for generating “gut sounds.” The rhythmic peristaltic churning of food mixed with fluids within the gut varies in slower waves depending on meal time, the meal itself, and the level of activity. You don’t actually “time” bowel sounds, but you do want to know if they are present.

Anatomy of the Gut

Veterinarians often joke that the abdomen of the horse was designed by a committee: it is complex and the obvious source of our leading killer, colic, which literally means pain with an abdominal origin. The horse has a unique abdominal anatomy, with the gut being within a space also shared by the liver, kidneys, and spleen. The reproductive organs also are present in females, with pregnancy being almost like the ever-enlarging living tumor. In males, the reproductive organs originate within the abdomen, then descend.

If we follow an oat kernel from the time of ingestion to digestion, it is quite a trip with strategic digestive processes. Anatomically, after the esophagus empties into the stomach, food and water begin transport through the abdominal viscera. The stomach is relatively small (2-4 gallons) and empties into the small intestine. Compare that to the 40-50-gallon vat called the rumen in the cow. If that oat kernel runs into a problem in the stomach of a cow it can be churned, fermented, and regurgitated for more chewing (cud). The horse is a species that does not regurgitate or vomit, thus the kernel is either trapped there or slowly exits into the duodenum, travels on to the jejunum and then the ileum, a trip of about 70 feet in length for the cumulative small intestine.

The small intestine ends with the muscular ileum that empties into the large colon and cecum, collectively called the “hindgut.” Foals become hindgut fermenters at about three to four months of age. The cecum in the horse serves as a blind but large fermentation sac located on the right side of the abdomen. The large colon also originates there at the junction of the ileo-cecal-colic valve, a favorite site for tapeworms. The cecum and colon are significant fermentation processing plants, with the large colon starting on the right, circling forward toward the diaphragm then going along on the left, folding upward and back on itself, before again going forward then passing back over to the right side to end with the junction to the small colon