People have historically put yokes on cattle and gotten them to do work like horses, but horses are more playful animals by nature, and they enjoy racing for sport.
It's a sure bet somebody is gambling on a race event somewhere, even if you aren't.
It's also a sure bet somebody is sneaking into the horse stables and doping one horse down or amping another horse up with illicit veterinary supplies.
Meanwhile the fans are drinking plenty of beer, and doing "legal" marijuana in interstate commerce with the protection of the usual Mob at such events.
And I'm not sure the horses even know when it's time to start, because guns are banned and no one can fire a pistol to start the race wihout getting arrested for felonious felony possession of an illegal firearm by a felon, and put away immediately for life without parole under a "three strikes" rule. The defendant is then supposed to count himself lucky he accepted the plea bargain so the D.A. didn't ask for the death penalty or impose it unofficially "off the books" in prison.