The field rounded the first turn with the Twin Spires of Churchill Downs in the background during the 144th Running of the Kentucky Derby. Justify (7) with Mike Smith up won and went on to the Triple Crown. This year’s Derby will have a record purse of $3 million. | PABLO ALCALA/Herald-Leader

By Janet Patton | Lexington Herald-Leader

Churchill Downs, home of racing’s biggest day, the Kentucky Derby, announced on Thursday that it and other Triple Crown racetracks would begin phasing out the use of a controversial race-day medication, beginning next year.

Lasix use will be eliminated in all stakes races at the racetracks beginning in 2021, according to the announcement.

The coalition includes tracks owned by Churchill Downs Inc., The Stronach Group, the New York Racing Association and others, including Keeneland, Del Mar, Lone Star Park and Remington Park, Los Alamitos Racecourse, Oaklawn Park and Tampa Bay Downs.

Together, these tracks represent 86 percent of the graded or listed U.S. stakes races this year, according to the coalition.

The coalition said it would work “diligently with their respective horsemen’s associations and racing commissions towards implementing this effort,” according to the release.

The use of Lasix, or furosemide, has become controversial in Thoroughbred racing with many arguing that it amounts to a performance-enhancing drug, if only for its potent diuretic effects. Others argue it is a necessary anti-bleeder medication. However, it isn’t allowed in most racing jurisdictions outside the United States.

Every Kentucky Derby horse, including eventual Triple Crown winner Justify, was on Lasix last year, according to the Churchill race-day program. Only two horses in the 14-race Derby Day card were not on Lasix, according to program.

Beginning Jan. 1, 2-year-old horses will not be allowed to be treated with Lasix within 24 hours of a race, and in 2021, the prohibition would extend to all horses in stakes races at the tracks.

That means in 2021, the Triple Crown races of the Kentucky Derby, Preakness and the Belmont will be run Lasix-free for the first time in decades, if the coalition’s “house rules” remain in effect.

The Breeders’ Cup and other racing organizations voiced support for the new policy, which has been one of the main goals of many in the horse industry as well as animal activist organizations for years.

“This is a huge moment that signals a collective move to evolve this legacy sport,” said Belinda Stronach, chair and president of The Stronach Group, which owns Santa Anita, where 23 horses have died in fatal breakdowns this year, as well as Pimlico, where the Preakness will be run.

Bill Carstanjen, CEO of Churchill Downs Inc., said the new rule “is a significant and meaningful step to further harmonize American racing with international standards.”