Why some horses are ‘bleeders'

Some racehorses bleed copiously from their nostrils after racing. Recent research has shown that a promising drug may prevent this condition, says Dr Mac.

- Dr Mac

Racehorse trainers call a horse that starts bleeding copiously from its nostrils during, or after, a race, a ‘bleeder’. The term has been in use for several centuries and is usually associated with Thoroughbred racehorses, although it also occurs in other breeds. Many breeders consider it a hereditary trait and try to exclude bloodlines that show a high proportion of racehorses that are bleeders. If a horse starts bleeding during or after a race, it is disqualified. Should it happen a second time, it may not be raced again. Over time, it has, however, also been shown that this condition is more common in horses that gallop very fast.