Figure 1 shows the horse's digestive tract with approximate lengths and capacities of various compartments of the tract. This diagram has been stretched out for demonstration purposes and thus is not anatomically correct. Figure 2 is a closeup of the major components of the horse digestive tract. Digestive Tract of the Horse. The foregut includes the mouth, esophagus, stomach and small intestine.
Digestion begins in the mouth where feeds are chewed and wetted with saliva.
The chewing process cracks the outer shell of grains, reduces the particle size of feeds, and increases the surface area of food particles. The horse's stomach is small, relative to the total tract, and cannot accommodate large quantities of food at any one time, resulting in eating several times per day due to limited one-time capacity. Limited enzymatic digestion and some fermentive digestion from a small microbial population occurs in the stomach. Food remains in the stomach only about 15 minutes before it starts to pass into the small intestine. This limited capacity and any excess gas products in the stomach can cause the rupture of the stomach, other digestive upsets and death.