Calkins are the prominent parts at the extremity of a horseshoe, bent downwards, and the edges blunted. They often occasion horses to trip, and sometimes also produce the bleyme, or an inflammation in the foot between the sole and the bone ; while the disease is communicated to the back and the sinews.

Calkins, when formed like a hare's ear, and if the horn of a horse's heel be pared pretty low, seldom do much damage; but when left large and square, they spoil the foot entirely. There are single and double calkins, accordingly as they are made at one or both ends of the foot: the latter, however, are but rarely hurtful, and generally make a horse trot more even and steady.