After a relatively smooth recovery, Barbaro underwent three procedures in less than a week, the latest for a new infection and "potentially serious" complications to his injured right hind leg.
"He was definitely not comfortable and they found the source of the discomfort and did something about it," owner Gretchen Jackson said Monday. "He was a lot more comfortable yesterday and, as I understand it, even better today."
Barbaro developed an infection in the leg in which a titanium plate and 27 screws were inserted after he shattered three bones at the start of the Preakness on May 20.
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," Jackson said. "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."
Surgery was performed by Dr. Dean Richardson at the University of Pennsylvania's New Bolton Center, where Barbaro has been recovering in the intensive care unit.
In a statement released by the hospital Sunday, Richardson emphasized that the complications are "potentially serious."
"Barbaro had developed some discomfort and a consistently elevated temperature so we believed it was in his best interest to remove the hardware and thoroughly clean the site of the infection," Richardson said. "We also applied a longer cast on that leg for additional support."
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. Barbaro is also being treated for a small abscess on the sole of his left hind hoof, according to the hospital.
Richardson said Barbaro's main fracture is 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."
"Maybe we've been lucky that we haven't had any big problems," owner Roy Jackson said. "Then a little problem like this crops up. The whole recovery is a difficult thing."
Barbaro took longer to recover from the anesthesia from Saturday's procedure. Richardson said the colt was back in his stall and receiving pain medication, antibiotics and "other supportive care."
The Jacksons, who live in nearby West Grove, Pa., and trainer Michael Matz continue to visit twice daily, the statement said.
"He looks all right," Roy Jackson said. "He looks fairly bright."
Doctors have said it could be months before they know if the colt can survive what has been called catastrophic injuries that leave him vulnerable to infection and other life-threatening complications.
Barbaro won the Kentucky Derby by 6 1/2 lengths, was unbeaten in six races and expected to make a Triple Crown bid before his misstep early in the Preakness ended his racing career. He was taken to the New Bolton Center hours after breaking down at Pimlico Race Course and underwent five hours of surgery the next day.
At that time, Richardson said the chances of the horse's survival were 50-50.