exercise-induced pulmonary hemorrhage

Exercise Induced Pulmonary Hemorrhage (EIPH) also known as "bleeding" or a "bleeding attack" has been known to occur in horses that engage in short periods of strenuous exercise. These horses usually include Thoroughbred and American Quarter Horse racehorses (incidence of 50-75%) and standardbred racehorses (incidence of 40-60%), but it may also occur in jumpers, polo ponies, and draft horses that pull competitively. It appears rarer in stallions than mares or geldings, but it is associated with airway inflammation and increasing age.
See more at Wikipedia.org...