No or very little turnout
Working horses so hard they bleed from the nose
Breakdowns from starting work at 2
Hocks ruined after 5 years
Breeding ridiculous numbers of horses only to "throw out" the excess
Nurse mare farms
I don't see how anyone could possibly be pro-racing (at least as it's run in North America). There might be good and bad in every sport, but that doesn't mean that all sports start out equal - some are inherently less humane than others. It's a shame, too, because when you get down to it racing really is one of the most natural things for a horse.