Respiratory problems in the racehorse.

Racetracks are ideal environments for the promotion of lower respiratory disease. The stabling is close and unclean, the population is nationally and internationally mobile, and the work the racehorse performs is traumatic to the respiratory tract. The running horse must complete a respiratory cycle with each stride. This relationship requires 130-150 breaths a minute in the running horse. Minute volume has been measured at 1300 L per minute and peak flow rates of 60 L/second in horses traveling at a modest 8 meters per second. As a comparison, the fastest running horse approaches 18 meters per second. The traumatic nature of racing to the respiratory tract is demonstrated by the fact that over 80% of the Thoroughbred racehorses show signs of exercise-induced pulmonary hemorrhage. Treating respiratory disease is a major part of racetrack practice.