Via Incertus, a New York Times article by William Rhoden castigating horse racing in light of the putting down of a horse at the Kentucky Derby. Quoting.....
The sport is at least as inhumane as greyhound racing and only a couple of steps removed from animal fighting.
I'm not sure I entirely agree, if only because greyhound racing has a horrible reputation. Racehorses are treated pretty well in comparison; too much money is spent on them to risk their health, at least while they can race and/or breed. Of course, not much is said about what happens to the has-beens, but from what I gather many still enjoy a typical horse life after they're done racing. I do see the possibility of more injuries,though, because of the way these horses have been bred to be strong and fast and almost impossibly thin-legged.
In other horse-related items I've happened across, Dale over at Faith in Honest Doubt expressed his bafflement at people who enjoy horse racing (and NASCAR), and Slate has a number of posts, including the decline in track attendance, whether racehorses live up to an old saying, and the attempts of an Arab Sheik to win the Kentucky Derby.