Churchill Downs

A horse gets a bath after a morning workout at Churchill Downs Friday, May 6, 2016, in Louisville, Ky. The 142nd running of the Kentucky Derby is scheduled for Saturday, May 7. (AP Photo/Charlie Riedel)

Charlie Riedel/AP

A horse gets a bath after a morning workout at Churchill Downs in Louisville, Kentucky. The 142nd running of the Kentucky Derby is scheduled for Saturday 

Riders get ready for their morning workouts at Churchill Downs Thursday, May 2, 2013, in Louisville, Ky.

David Goldman/AP

Horse riders get ready for their morning workouts at Churchill Downs, in Louisville, Kentucky in the US