Why do Thoroughbred racehorses bleed from the lungs and why do you see so many 2-year-old runners already being administered Lasix?
Dr. Waterman: Just about all horses bleed (90+%). From those running around in the pasture to Quarter Horses barrel racing to Clydesdales pulling the Budweiser cart to Thoroughbreds on the track, they all suffer from Exercise Induced Pulmonary Hemorrhage to varying degrees at maximal exertion. It is part of being a flight animal as opposed to a fight animal. The reason you see many 2-year-olds on it is that many veterinarians feel that the earlier in the career of the horse you begin furosemide, the less the horse will bleed over the course of his/her career. There is some preventative effect in controlling bleeding before it becomes a chronic problem. Blood is not normally found in the lung tissue and airways so when it is present it creates inflammation. That inflammation makes it more likely the horse will bleed again. Certainly there is some everyone else is on it so I should be too, but there are valid reasons to use it at a young age.
