Following a four-month-long undercover investigation conducted by the animal welfare group PETA last year, activists have unearthed disturbing footage of alleged abuse at one of the country's premier horse training facilities. On Tuesday, PETA filed complaints with federal and state agencies in Kentucky and New York, charging that horse trainer Steve Asmussen -- who ranks second in career horse racing victories and has earned more than $214 million in his thoroughbred ventures -- and his top assistant trainer, Scott Blasi, "forced injured and/or suffering horses to race and train."

According to the New York Times, which was given advanced access to the seven hours of video footage PETA recorded, the investigation found horse abuse to be "widespread and cavalier" at Asmussen's Kentucky-based operation:

Video clips and the report depicted the Asmussen barn and the backsides of two of the United States' most storied racetracks as places where horses were treated as commodities and given numerous joint injections as well as tranquilizers, painkillers and supplements ...

Blasi was recorded discussing injured horses, as well as how one of his jockeys, Ricardo Santana Jr., 21, used a buzzer to shock horses, a practice that is banned in racing.