Due to the constant pounding in training and racing, Susan Stover says, many Thoroughbreds end up with microscopic bone damage as the injured horse swaps damaged tissue for new tissue. However, the University of California veterinary researcher at Davis, Calif., found that more than 90 percent of tissue sampled from racehorses that had died or were euthanized after leg fractures had pre-existing bone damage.

At first glance, a toe grab seems like a very little thing. Even the toe grab on a Quarter Horse racing plate (the highest type of toe grab) is less than 1/3-inch high.