Exertional rhabdomyolysis in a 4-year-old standardbred filly.

A young standardbred filly became stiff and uncomfortable after racing. A day later, creatine kinase, aspartate aminotransferase, and lactic dehydrogenase levels were markedly elevated. Exertional rhabdomyolysis was diagnosed. Limited exercise and a low carbohydrate, high fat diet were prescribed. Eight days later, the filly was raced again without consequences.