FRANKFORT, Ky. (AP) -- Kentucky Gov. Steve Beshear signed an emergency regulation Friday banning steroids for the state's thoroughbred and standardbred races.

The new rules go into effect immediately and ban anabolic steroids from being present in the blood of any horse that's racing. Horse regulators approved the sweeping ban earlier this month.

Big Brown had steroids in his system before winning the Kentucky Derby and Preakness Stakes. It was not illegal in any of the Triple Crown states this year, and Big Brown's trainer, Rick Dutrow, has said he only uses it to brighten his horses' coats and increase their appetites.