The debate over the use of drugs in race horses has made it all the way to Capitol Hill where Congress has held hearings on banning substances used to dull pain in equine athletes allowing them to run faster.
Far less well known is the use of a wide array of drugs, including cocaine and anti-psychotics, to do the opposite in the show ring: calm horses so they perform better in classes where an easy rocking horse pace is expected.
A report in Friday's New York Times reveals widespread drug use in equestrian sports right up to the Olympic level. In dozens of random tests since 2010 it found dozens of instances where horses had been drugged before competitions. 
The focus of the story was the sudden death in May of Humble, a top show pony, who collapsed at the storied Devon Horse Show. He had been scheduled to receive 15 drug treatments in the three days before he died, the Times reports.
The horse show world is far from immune to scandal involving the cruel treatment of animals. Perhaps the most shocking case was the electrocution killing of high-priced horses for insurance money exposed in the 1990s that sent several leading riders and trainers, George Lindemann Jr., and Barney Ward among them, to prison.
The practice of "soring" or putting acidic products on horses legs to make them step higher has been outlawed at Tennessee Walking Horse Shows, however with few inspectors the practice continues even among top trainers exposed through investigations by the Humane Society of the United States.  
There have been calls for increased policing of equestrian events, the Times reports and Humble's tragic death prompted the horse show world's governing body, the United States Equestrian Federation, to launch an investigation into drug use among its competitors. It also temporarily suspended Humble's trainer, Elizabeth Mandarino of New Jersey, in connection with the pony's death.
See New York Times video here.