http://www.nytimes.com/2012/03/25/us/de ... odayspaper
I thought this an interesting comment in the article.
. . . the new economics of racing are making an always-dangerous game even more so. Faced with a steep loss of customers, racetracks have increasingly added casino gambling to their operations, resulting in higher purses but also providing an incentive for trainers to race unfit horses. At Aqueduct Racetrack in Queens, the number of dead and injured horses has risen sharply since a casino opened there late last year.