The horse digestive system is one of the best places to start understanding horse nutrition. After all, if you don't know what goes on in there, the rest will all be Greek to you!
First things first -- horses are herbivores. They are designed to eat plants, which should make up the horse’s entire diet in one form or another.
They are also non-ruminants, and have what is referred to as a “simple stomach” -- one compartment that functions a lot like your stomach.
The anatomy of the horse's digestive system is fairly simple and straightforward, as it is much like yours with only a few minor differences. Starting from the top, the digestive system is composed of:
The major difference between the horse and you is the importance of the cecum to the horse, whereas our appendix (which is the closest thing to the horse's cecum) is almost non-functional in humans.
Digestion of diet components take place in specific areas of the tract. If something happens where it shouldn’t, problems and digestive upset can easily occur.
Don't let your horse fool you -- no matter how "big and bad" he likes to think he is, his digestive system is still delicate. Some days I wonder why I couldn't love something with a more sturdy digestive system, like a cow...
Anyways, back to the delicate digestive system. Colic (digestive upset) is a serious concern to most horse owners since it takes so little to throw the horse digestive system off. Something as simple as missing a few meals can cause colic.
This disease is complicated by the fact that horses are unable to vomit (thanks to extra strong muscles surrounding the opening between the esophogus and stomach). The best way to prevent colic is to understand how the digestive system of your horse works!
Almost all digestion of simple carbohydrates, protein, and fat takes place primarily in the small intestine, though it begins in the stomach. Simple carbohydrates (starches and sugars) and protein begin digestion in the stomach by being slightly broken down, and then the majority of the digestion of these nutrients occurs in the small intestine. Fats are slightly hydrolyzed by enzymes in the stomach, but the majority of fat digestion also occurs in the early small intestine.
On the other hand, complex carbohydrates (cellulose, lignin) are digested mostly in the cecum and somewhat in the colon. There is also a small amount of protein that may be digested in the large intestine. The cecum and colon is where the microbes that digest the fiber in your horse's diet (most of the contents of hay, pasture, beet pulp, etc.) live, so these areas are where these substances are finished digesting.
For a closer look at these individual nutrients, check out their pages:
Now that we've looked at the horse digestive system, let's move on to some other areas of horse nutrition.
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