The Associated Press
John Velazquez rides Uncle Mo to victory during the Juvenile race at the Breeder’s Cup on Nov. 6 at Churchill Downs, in Louisville, Ky.

Some prominent owners and breeders are pledging to run their 2-year-olds this year without race-day medications, putting themselves in the middle of a debate about the role of drugs in thoroughbred racing.

Among those making the pledge are Barry Irwin's Team Valor International, which won the 2011 Kentucky Derby with Animal Kingdom, and Roy and Gretchen Jackson, the owners of 2006 Derby winner Barbaro. Others include Lane's End Farm owner William S. Farish and Seth Hancock, who syndicated Secretariat.

WinStar Farms' Bill Casner, who won the 2010 Derby with Super Saver, calls race-day medications a "failed experiment."

The Thoroughbred Owners and Breeders Association released the list Thursday.

Kentucky horse racing regulators recently approved an eventual ban on race-day use of the anti-bleeding drug furosemide in graded or listed stakes races.