I only watched about 1/2 hour of the pre-race show (I always love how the network has to work to turn a 2.5-minute race into a 2-hour TV event). I have to admit -- watching how inevitable everyone was treating a Big Brown win, I figured he wasn't going to be able to pull it off. Karma does not like to be mocked.
I definitely hope he's OK, that it was just him thinking, "It's hot, I'm tired, my foot is bugging me, I'm not up for this today" rather than something more serious.
I feel rather sorry for Da'tara and everyone connected with him, news-wise. No one paid the least bit of attention to him even after he won -- it was still all about Big Brown. And leading for the entire race for a mile and a half is impressive even if it was a relatively slow Belmont Stakes.