Equine Digestion 101
Did you know that your horse's digestive system is nearly 100 feet long?
It all starts in the 4.5 foot esophagus. Food enters the esophagus and travels to the stomach. Once in the stomach, food cannot come back up. The esophageal sphincter is what keeps a horse from being able to vomit.
Protein digestion begins in the stomach. The stomach is relatively small and cannot handle large meals over 3-4lbs (for average size horses). Because horses are slow feeders by design, large meals of feed can easily overload the stomach leading to colic and other serious issues. The stomach is also home to hydrochloric acid, the culprit of most ulcers. Hydrochloric acid aids in breaking down food and kills the microorganisms ingested while eating. However, the stomach performs only a small amount of breakdown in the digestive process.
Once the stomach acid has done it's job, food matter passes into the 70 winding feet of the small intestine. Protein, carbs, starch, sugar and fats are digested in the small intestines. This is where particles enter the bloodstream and are distributed to the rest of the body. If too much starch and sugar are consumed, the small intestine cannot process it all and the remainder passes into the cecum which can be dangerous. In addition, too much starch and sugar can send glucose levels on a roller coaster ride that can be very troublesome for the horse.
At this point, forage has traveled approximately 75 feet inside the horse before any breakdown of fibrous material occurs. The next stop is the cecum where fiber breakdown happens. The 4 foot cecum produces the enzymes necessary to digest fiber. If starch and sugars are allowed to pass into the cecum, pH levels decrease and the risk of laminitis increases. Therefore, feeds high in starch and sugar should be limited to small amounts so that breakdown occurs in the small intestine, prior to entering the cecum.
The cecum, along with small colon (10-12ft), and the large colon (10-12ft) break all remaining feedstuffs. This can take 48-72 hours before being excreted as manure.