Odds On Racing - Harness Racing

Why Horses Race on Lasix
By Kimberly A. Rinker

For horses that race on the state-monitored medication "lasix," an (L) will be found just to the right of that horse's name in the program. But what does this really mean, to the horse, to the trainer, and to the public? Why do these (L) horses need lasix, or Salix, as it is now referred to, and what are the effects of lasix on a horse's system?

Lasix, whose technical name is furosemide, is used as a preventative treatment for "Exercise-Induced Pulmonary Hemorrhage," a very common occupational disease which affects the lungs of race horses. Horses with "EIPH" will bleed from the lungs during intensive exercise, with Standardbreds, of course, that's harness racing. Most of the time the hemorrhage (bleeding) is minor, although in rare cases it can be intense.

The cause of EIPH or "bleeding" is stress. Although a horse may be treated with the best of care by his trainer, he could still bleed internally in his lungs. Nearly all horses bleed to some degree, just as in human athletes who compete in high-stress sports. However, most of the time the bleeding is inconsequential and no external bleeding is found. In fact, it is considered by some to be a natural, circumstantial response to all racing efforts. It is traumatic in nature, self-limiting, and heals spontaneously without the need for treatment. Time is it's best friend.

EIPH is a disease with a long history, and one that has been common throughout the racing industries, both harness and thoroughbred. With the introduction of the fiber optic endoscope in the early 1970's, veterinarians were, for the first time, allowed the safe and effective visual image of the upper respiratory tract of horses. With this scope, veterinarians are able to determine that blood observed in the trachea had actually originated from the lungs.

Until that time, the conditioned was thought to be a nosebleed and to have originated in the head. The use of lasix was first and still is widely used on humans. Lasix, which is a diuretic, has been shown to reduce hemorrhage on horses under high stress and racing conditions.

Racing jurisdictions that allow the controlled use of lasix, limit the amount of furosemide and its administration to approximately four hours prior to race time to avoid any diluting effect which may complicate post-race drug testing of the urine. Thus, lasix will not interfere with the drug-testing procedure when used in a prescribed manner.

Lasix does, however, cause a horse to lose delicate body fluids such as electrolytes. That is why a trainer who conditions "lasix" horses will often have their veterinarian administer electrolyte "Jugs" to their horses, to replace the vital fluids that horse has lost.

During the normal process of racing, a horse will lose a great amount of water, and a horse on lasix will loose twice that of a normal horse. Therefore, it is imperative that the trainer endeavor to replace the horse's vital fluids. Besides having the veterinarian give the horse an electrolyte jug intravenously, a trainer will also often place electrolyte powder in the horse's water bucket or in his feed on a daily basis.

A horse's body is an amazing and complex piece of equine machinery that can adapt and repair itself time and time again. With the advent and controlled medication of lasix, horses are able to race and perform to the utmost of their ability, while maintaining their normal level of fitness.