Understanding Your Horse’s Digestive System

The small intestine is also a common location for many types of parasites, like roundworms and strongyles. Heavy parasite infestations can damage the lining of the small intestine, which hurts the horse’s ability to absorb nutrients and can result in weight loss and diarrhea.

Hindgut

So far, the horse’s digestive system has been similar to ours. But once out of the small intestine, we enter the maze of the hindgut. First stop: the cecum.

The horse’s enormous digestive tract takes many twists and turns. The majority of digestion takes place in the cecum and large colon. Photo by Gerasimov Sergei/Shutterstock

The cecum is a large, dead-end pouch-shaped organ on the lower right side of your horse’s belly near his flank. The cecum is where food is mixed with water and healthy microbes that always live inside your horse. These microbes are vital to the digestion of tough, fibrous food like grass and hay. A horse can’t digest this fibrous material on his own. Without these tiny creatures, he could not survive.

After several hours of fermentation (breakdown of food) in the cecum, food exits and is routed to the large colon, where fermentation continues—it’s a long process! Remember how the cecum is on the right side? After leaving the cecum, food enters the first part of the large colon, called the ventral colon. Ventral means “bottom,” so this part runs along the bottom of your horse’s belly.

Near the pelvis, food takes a sharp turn straight up to the top of the horse in what is now called the dorsal colon. Dorsal means “top.” This tight turn is a common place for impaction colic, because it’s easy for food to get stuck here.

Near the pelvis, the large colon takes a sharp turn, which is a common area for impaction colic. Your vet will listen for normal or absent gut sounds if an impaction is suspected. Photo by 135pixels/Shutterstock

Once up in the dorsal colon, food travels toward the horse’s head again and makes a right turn behind the rib cage, heading back toward the tail for a short section called the transverse colon.

After this, guess what? Yep, still more colon! But we are getting to the end; next is the small colon, the final place of last-minute fermentation and absorption of water and nutrients. The small colon has tight muscular bands that mold the digested food into the characteristic manure balls we all know.

Then, it’s on to the rectum and out the horse—digestion complete!