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Chapter 5. A Horse’s Digestive System

A Horse’s Digestive System

A horse’s gut is designed to digest small amounts of food frequently. Horses cannot vomit, and will colic. “Colic” is a general term meaning abdominal pain.

Horse Digestive System

Horse Digestion

A Horse’s Gastrointestinal (GI) Tract

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Did you know it takes up to two to three days for food to completely pass through a horse's digestive tract?

The GI Tract of a Horse

Consists of the mouth, esophagus, stomach, small intestines, cecum, large colon, small colon, and rectum.

Horse Digestion

Mouth

Digestion begins in the mouth. The horse’s teeth chew the food and they produce saliva which starts digestion.

Esophagus

The horse’s esophagus transports food from his mouth to his stomach.

Horses cannot throw up, and their stomachs are very small compared to their large bodies. If a horse eats too much feed at once, he can colic or even rupture his stomach.

Cecum

Roughage is fermented (digested) by microbes In the cecum. Horses have a very large cecum because they eat high fiber diets. The horse’s cecum is about 4 times as big as his stomach.

Stomach

The stomach secretes a strong acid that begins digestion and also kills bacteria. Some stomach cells secrete a protective mucous to keep the stomach acid from harming the cells lining the stomach.  Food material does not stay in the horse’s stomach very long because the stomach is so small (it is only about 2 gallons in a 1,000-pound horse).

Large Intestines

Some fermentation occurs by microbes that live in the first part of the large intestine. As material passes through the rest of the large intestine, water is absorbed back into the horse’s body.

Small Intestines

The small intestine is where most digestion occurs due to the enzymes the horse secretes. These enzymes can digest (break down) starches, proteins, and fats.

The small intestine is where almost all of the nutrients are absorbed into the horse’s bloodstream. Any nutrients that are not absorbed into the bloodstream are lost in the manure.

Rectum

Undigested food is expelled through the rectum.