Racehorses must be healthy and at their peak fitness to be successful. One commonly combated health condition—exercise-induced pulmonary hemorrhage, or EIPH—can be performance-limiting and even deadly among these athletes. And as racehorse medication reform has taken center stage in recent years, the racing world has been rife with controversy over whether to allow horses in America to race while medicated to help control the condition, or to implement a medication-free racing policy, as some racing jurisdictions overseas have.

During the "Current Controversies" session at the 2013 American Association of Equine Practitioners’ Convention, held Dec. 7-11 in Nashville, Tenn., Rick Arthur, DVM, looked back at the condition’s history, what it does to the horse, and how veterinarians currently treat it.

Arthur, of the University of California, Davis, and the equine medical director for the California Horse Racing Board, explained that two very famous racehorses and prominent sires, Eclipse and Herod, were bleeders. Their bloodlines factor strongly in subsequent generations, so it’s not surprising that many horses competing on today’s racetracks exhibit EIPH.

Arthur said that veterinarians originally thought that the bleeding derived from injury to the blood vessel-rich area within the head. But, in 1974, with the advent of a simple fiber-optic scope, Robert Cook, FRCVS, PhD, identified that the bleeding was coming from the blood vessels within the lungs. This discovery modified how veterinarians approach this syndrome, both diagnosis and treatment. John Pascoe, BVSc, PhD, Dipl. ACVS, and colleagues coined the term "exercise-induced pulmonary hemorrhage" after conducting research Thoroughbred and Standardbred racetracks in the late 1970s, in which they examined horses post-race using a fiber-optic endoscope, Arthur added