> Millions of horses are raised every year for their meat.
I don't know enough about the numbers worldwide to give you real hard data but the majority of all of the horse meat consumed worldwide is not from horses bred with the sole purpose to breed it for it's meat. I have the idea that it's not more than 30%.
Also the horses that are primarily bred for food are for a large part free roaming in places where other cattle simply wouldn't survive. This in contrast to other meats (chicken, veal, pork) that are often raised in factory like environments.