LOUISVILLE -- Hearts sank as Thunder Snow came out of the gate at the 143rd Kentucky Derby on Saturday at Churchill Downs and immediately started bucking, falling way behind and not finishing.

Bucking can indicate an injury, and it is saddening to see a race horse injured on the track during a race. Everyone remembers the heartbreaking death of a horse during the 2008 Derby.

But Thunder Snow was taken by an outrider and was eventually able to get back to the paddock after the race.

Dr. Keith Latson, the veterinarian for the Kentucky Derby, said after the race that Thunder Snow comfortably galloped back, and he was examined by Dr. Jennifer Kaak.

"He didn't break well," Latson said. "She found no injuries on the leg, so the horse was allowed to walk back under his own power and did so comfortably."

More than likely it was an issue in the gate, or Thunder Snow just wasn't feeling it in the sloppy conditions. Bucking is more common for untrained race horses. But Thunder Snow has excelled, winning the UAE Derby and UAE 2000 Guineas earlier in 2017.

Always Dreaming pulled away down the final stretch to win the Derby. Here is the full race. Thunder Snow can be seen bucking in the back:

PHOTOS | Celebs and their hats at the Kentucky Derby