Kennett Square, Pa. ? Kentucky Derby winner Barbaro was facing major problems for the first time since surgery to repair the right hind leg he shattered in the Preakness seven weeks ago, with the colt’s veterinarian saying “we’re in tough times right now.”

Barbaro had the cast on the leg replaced for a sixth time Monday – the fourth time in a week. The latest development followed many hours of surgery Saturday night when doctors replaced the metal plate and many screws and also treated an infection.

“I think we’re in for tough times right now. I think we’re going to have some tough days ahead,” Dr. Dean Richardson said at the University of Pennsylvania’s New Bolton Center. “I’m being realistic about it. When a horse has a setback like this, it’s a problem.”

Richardson, the chief surgeon at the New Bolton Center, looked haggard during the briefing, and said it took more than 15 hours from the start of Saturday’s surgery before Barbaro had fully recovered from anesthesia.

He said Barbaro was back in his stall in the intensive care unit, where he’s been since the catastrophic injury occurred just a few hundred yards after the start of the Preakness.

“Right now, he’s happier,” Richardson said. “He’s got a normal heart rate, normal temperature, he’s eating like crazy. He’s very hungry. He’s making lots of manure. He looks actually pretty happy today. Now we have to see how he responds to what’s going on.”

The long cast applied Saturday night was replaced by a shorter cast Monday, and “was done with Barbaro in a sling and under mild sedation,” Richardson said.

“The long cast was used as extra support during the anesthetic recovery phase,” Richardson said. “It is much easier for him to move around his stall and get up and down with a short cast. We also found and treated an abscess in his left hind foot that was bothering him.”

Barbaro is receiving pain medication, antibiotics and other supportive care, Richardson added.

After a relatively smooth recovery, Barbaro has now undergone three procedures in less than a week.

The infection developed in the leg in which the titanium plate and 27 screws were inserted after Barbaro’s catastrophic injury at the start of the Preakness.

After Barbaro showed discomfort and had a “consistently” high fever, the plate and screws were replaced and the infection treated late Saturday night.

“It’s one of those setbacks that we’ve prepared ourselves for as best we can,” owner Gretchen Jackson said Monday. “Sure it’s disappointing, but we’ve been warned. … But a lot of bone has healed, a lot. There’s a lot of good stuff. And the horse is incredibly strong, healthy and we’ve got to keep the faith.”

Last Monday, Barbaro had the cast on his injured leg replaced and three new screws inserted. On Wednesday, another new cast was applied after the horse showed discomfort.

Richardson said Sunday that Barbaro’s main fracture was healing well, but the pastern joint – located above the hoof which was shattered into more than 20 pieces – continues to be a concern. The joint, which doctors are attempting to fuse, was stabilized with “new implants and a fresh bone graft.”