Barbaro underwent more than five hours of surgery Sunday to repair the rear leg bones he broke in the Preakness, calmly awoke from anesthesia and "practically jogged back to his stall" for something to eat.

But the Kentucky Derby winner still faces a 50-50 chance of survival.

Despite the successful procedure and signs that the strapping 3-year-old colt had made a huge first step on the road to recovery, Dr. Dean Richardson said Sunday that Barbaro's fate still came down to "a coin toss."

"He practically jogged back to his stall," Richardson said after the surgery at the University of Pennsylvania's New Bolton Center for Large Animals. "Right now he's very happy. He's eating, he's doing very good. But I've been doing this too long to know that day one is the end of things."

Barbaro sustained "life-threatening injuries" Saturday when he broke bones above and below his right rear ankle at the start of the Preakness Stakes. His surgery began around 1 p.m., but it wasn't until about eight hours later that Richardson and trainer Michael Matz emerged to hold a news briefing.

"From the last time I saw him to now was a big relief," said a visibly fatigued Matz. "They did an excellent job. It's just an amazing thing to see him walk in like that.

"I feel much more comfortable now. I feel at least he has a chance."

Unbeaten and a serious contender for the Triple Crown, Barbaro broke down Saturday only a few hundred yards into the 1 3-16-mile Preakness. The record crowd of 118,402 watched in shock as Barbaro veered sideways, his right leg flaring out grotesquely. Jockey Edgar Prado pulled the powerful colt to a halt, jumped off and awaited medical assistance.