KENNETT SQUARE, Pa. — He still looks every bit the champion. Only the fiberglass casts on not one but both of Barbaro’s hind legs are indicators of something terribly wrong.

“His ears are up, he’s bright, he’s looking around,” Dr. Dean Richardson said Thursday. “If you look at this horse, it’d be hard to put him down.”

That precisely is the heartbreaking task that could be imminent because of a hoof disease so serious Richardson said the Kentucky Derby winner is “a long shot” to survive.

“It could happen within 24 hours,” Richardson said during a news conference at the University of Pennsylvania’s New Bolton Center.

Richardson said Barbaro has a severe case of laminitis in his left hind leg — a painful, often fatal disease caused by uneven weight distribution in the limbs.

“If he starts acting like he doesn’t want to stand on the leg, that’s it. That will be when we call it quits,” he said.

Richardson, who has treated Barbaro since the colt suffered catastrophic injuries in the Preakness on May 20, said 80 percent of the horse’s left hoof wall was removed Wednesday with the sudden onset of the disease.

Though he looks just fine, that doesn’t reflect the true nature of his condition, termed “poor” by Richardson.

“I’d be lying if I said anything other than poor,” he said.

“As long as the horse is not suffering, we are going to continue to try to save him. If we can keep him comfortable, we think it’s worth the effort.”

Until his misstep at the Preakness, Barbaro’s career was nothing short of brilliant.

He won his first five starts, including the Florida Derby. His 61/2-length victory at the Derby was so convincing he was being hailed as the next likely Triple Crown champion — and first since Affirmed since 1978.

But seconds after the gates swung open at Pimlico, that career was cut short when the colt broke down, his right hind leg flaring out awkwardly because of three broken bones.

The vet didn’t mince words: “It’s as bad a laminitis as you can have. It’s as bad as it gets.”