CAUSES OF DEATH IN RACEHORSES OVER A 2-YEAR PERIOD

Necropsies were performed on 496 horses that had a fatal injury or ill ness at a California racetrack during the period February 20th 1990 to March 1st 1992. The primary cause of death was categorised by breed, activity at time of injury or illness and organ system affected. Most of the submissions were Thoroughbred horses (432) and Quarter Horses ( 46). Most of the injuries occurred while racing (42%) and in training sessions (39%); with fewer non-exercise (12%) and accident (7%) relate d injuries or illnesses. Musculoskeletal injuries accounted for 83% of the Thoroughbred and 80% of the Quarter Horse submissions. The Thorou ghbred horses incurred 306 fractures with 263 in the limbs and 90% of those in the forelimbs. The proximal sesamoid bone(s), third metacarpa l bone and humerus were the most common bones fractured in Thoroughbre d horses and Quarter Horses. Other major causes of death included resp iratory, digestive and multi-organ system disorders.