If you notice a strange growth on your horse’s leg – there’s nothing to be worried about. They’re probably chestnuts or ergots, and they’re normal. Most important is that your horse’s health isn’t in danger.
No one really knows why horses have them. Some in the scientific world believe they’re inherited from early forms of horses who may have had an extra toe, called multi-toed Equidae. More specifically, they came from the vestigial toes of Eohippus, an early ancestor of the modern horse that lived 50 million years ago. Those scientists believe that as equines evolved, the ergots and chestnuts shrank and lost their original function. Some insist that they’ve become essentially scent glands.
In any event, chestnuts appear on the front legs of a horse above the knee, or sometimes on the back legs of a horse below the hock. Some are large, and some are small, but they’re usually more flat in appearance. They’re often scratchy. Ergots are found on the back of a horse’s fetlock on all four legs, usually covered with hair. They’re a little harder to see, so part the hair to find them. Ergots are a bit more pointy and feel like the end of an eraser on a wooden pencil.
You don’t really have to trim them. But if you’re so inclined, you can trim them without causing the horse any pain. Don’t try to remove them entirely, and don’t trim any deeper than skin level or above. Just peel them off layer by layer with your hands or fingernails. You could use a knife or similar sharp tool. However, they trim relatively easily by pinching them off (not twisting) with fingernails. Keep in mind that they come off easier when wet, so consider pruning them after a rinse or bath. The only time that ergots become an issue is if they’re so long they get snagged on fences.
These strange growths will likely grow back, so you might as well make trimming a regular part of grooming your horse. Fortunately, all of it is merely cosmetic.
