A short video cobbled together from a four-month undercover PETA investigation of a prominent horse trainer shows the underside of horse racing.

Earlier this year, PETA sent an undercover investigator to work for Steve Asmussen, a well-known trainer who has won more than $214 million in purses. Using a hidden camera, the investigator recorded Asmussen and his assistant subjecting their horses to painful medical treatments, often injecting them with tranquilizers and painkillers.

It's not alleged that any of the drugs were illegally administered, but the video suggests many of the horses were raced into the ground.

In a recorded conversation between Asmussen, his assistant Scott Blasi, and a blacksmith, the trio admit that Nehro, the 2011 Kentucky Derby runner-up, was raced so hard his feet were ground into nubs and his hooves were held together with super glue. Blasi continued to train Nehro, who died a year later. The trainers claimed it was from colic.

On the tape, Blasi says, "I have seen a lot of shit. That is the most violent fucking death I have ever seen."

In the film, Asmussen also admits one of his jockeys uses a buzzer to administer electric shocks, a practice that is banned in racing.

PETA also alleges Asmussen employed undocumented workers and paid the undercover investigator only $5.95 with no overtime.