Sudden death in training and racing Thoroughbred horses.

TitleSudden death in training and racing Thoroughbred horses.
Publication TypeJournal Article
Year of Publication1985
AuthorsGelberg HB, Zachary JF, Everitt JI, Jensen RC, Smetzer DL
JournalJournal of the American Veterinary Medical Association
Date Published1985 Dec 15
KeywordsAnimals, Death, Sudden, Female, Horse Diseases, Horses, Male, Physical Conditioning, Animal

We reviewed case records, necropsy reports, and histologic sections from 25 Thoroughbred racehorses that died suddenly at 3 Chicago racetracks. These were young horses ranging in age from 2 to 5 years. There were more females (n = 16) than males (n = 9), and the incidence of death increased slightly in the spring and summer. Twenty-one of the 25 horses died while racing or training. Only 8 of the 25 horses (32%) had lesions sufficient to account for the death. In 6 of those 8 cases, death was caused by massive thoracic or abdominal hemorrhage. The site or nature of the vascular defect in these cases could not be determined. One horse died of severe preexisting pulmonary disease, and one died of encephalitis and cardiac papillary muscle fibrosis. The cause of death was undetermined in 17 horses (68%). Nearly all horses had pulmonary edema, congestion, and/or hemorrhage. We postulate that these unexplained deaths were a result of exercise-induced acute cardiovascular failure.

Alternate JournalJ. Am. Vet. Med. Assoc.