Thunder Snow pulled up at the Kentucky Derby on Saturday evening at Louisville's Churchill Downs and did not finish the Run for the Roses. You can see the horse bucking immediately off the start in the official video of the race from NBC Sports.
Mike Tirico said on the NBC Sports broadcast that Thunder Snow did not show any signs of injury after an initial examination. And a Churchill Downs on-call vet also confirmed that Thunder Snow was not injured, per Katherine Terrell of ESPN.
"Thunder Snow has been checked by vets on course and appears to be sound," trainer Saeed bin Suroor said, per GoDolphin, adding: "We will closely monitor him over the next 24 hours to ensure that he is okay. Our first priority is his welfare."
Jeannine Edwards of ESPN added that the horse's wild start "appeared to be a saddle/girth issue."
Nicole Russo of Daily Racing Form showed the colt leaving the track after the race:
Thunder Snow came into the race with 16-1 odds from the No. 2 post position. He was ridden by Christophe Soumillon.