Cowboy Bob's Questions and Answers - page 210 - Why will a horse will eat its self to death?

Q&A Questions and Answers:

QUESTION:
Bob, can you tell me why a horse will eat their self to death (on sweet feed or etc.) while a mule, dogs, cats, etc. will eat until they get full and quit?

-- S. L.

ANSWER:

A lot of the answer to your question lies in the anatomy of the critter.

A mule, a horse, and a dog Dogs and cats simply don't have the size or length of internal plumbing that a horse does, so they get full faster and food is less likely to plug up the system. When it does, dogs and cats have the ability to heave to get rid of some of the excess food. If a cat or dog keeps eating too much, it usually just gets fat.

A horse, because it's a grazing animal, has a one-way valve that prevents food from coming back up the throat. Thus, it doesn't have the luxury of heaving. Since it's a grazing animal, a horse needs to keep its digestive system filled with roughage. If a more tasty feed is available, the horse will try to eat as much volume of the sweet stuff as it would of hay in order to fill the empty space in its belly. When that happens -- just like a kid who eats too much candy -- it gets a bellyache. In horses, a bellyache is called colic and can lead to founder.

Mules are another matter. In general, mules don't get colic from over-eating grain, but that's not a hard-and-fast rule. Mules from pony mares can and do occasionally develop colic or grain founder. While part of the answer lies in what's called "hybrid vigor" (the greater strengths that come from cross-breeding two dissimilar breeds), there are many aspects of a mule's strength and overall soundness that continue to baffle veterinarians and biologists.

The mule stopped grazing, the horse didn't The difference between horses and mules seems to be a combination of attitude and anatomy. Here are a few of those aspects:

Mules tend to eat less, so they are less likely to gorge on grain.
Mules are larger than horses, so their plumbing is larger and less likely to get plugged up. (This probably explains why the smaller pony mules have colic problems more like those of horses.
Mules seem to inherit a strong survival instinct from the donkey side of their breeding. That survival instinct seems to include having the wisdom to know when to stop eating.

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