No mane course? Why horse meat's off the menu The real hazard here, says James McWilliams, is "the hazard that horse meat poses to public health." Many of the horses that end up in slaughterhouses are thoroughbreds from the racing industry, or prolific breeders. Racing in particular exposes horses to overbreeding and extensive drug use - "Indeed," says McWilliams "many racehorses essentially become pharmaceutical dumping grounds throughout their artificially stimulated, sedated, and numbed lives." Not the kind of thing you'd want in a sandwich.