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.

Olin Balch urges you to carefully explain the risks to owners who ask you to perform corrective shoeing or trimming on young foals.