Here is a recent article in the New York Times: http://www.nytimes.com/2014/03/21/sport ... .html?_r=0
Now, I haven't read the entire article, so I'm not sure if it frames the issue as an isolated incident or a systemic problem. Of course horses love to run, as do greyhounds, and some people. But by and large in the racing of non-human animals, these animals are only valued for their ability to perform. Only a tiny fraction of horses are going to be champions -- so what happens to the rest? And how is a top performing horse's health and lifespan affected by the supposed "sport"?