Barbaro was definitely injured before the start of the race. I can't believe the number of people who have not gone back and watched the NBC broadcast tape which shows this. The tape after he broke through the gate clearly shows him trotting on three legs and holding the right rear leg up and he hops along...BEFORE the race.
I don't know much about horses, but I do know human nature. Barbaro wasn't going to be scratched from the race unless one of his legs actually fell off.
If it was so clear, don't you think others would have seen that? I didn't.