Well certainly qualified on an emotional level.
When I was a young man I spent a summer working with racing Greyhound dogs. The 'ranch', for lack of a better word, had about 150 of them. Now only a handful are money makers, and the rest eat a lot of food. Simple math, you get rid of the nonperformers. Multiply that racing dog operation by many many more around the country. Of course these days were more 'enlightened' and try to find good homes for the unwanted dogs. Yeah, that would be about 1 in 10, the rest, well, I could tell you some real horror stories. That summer scard me for life. We also raised rabbits, to train the dogs with, gruesome work that. Greyhounds love rabbits, trained that way from when their puppies.
Now I would imagine the numbers are lower in the horse race business, but the end result has got to be much the same. If it's a non producer, what to do with an animal that eats a lot and takes up your time? Oh, find him a nice home. Yeah, good luck with the other 9 out of 10.