Kentucky Derby winner Barbaro (pictured in December) has had a serious setback over the last 24 hours. Yesterday, when he became significantly more uncomfortable on his left hind foot, which is being treated for laminitis, his cast was removed and new separation of the medial (inside) portion of his hoof was found. Surgery was performed last night to remove the damaged tissue.

On January 3, Dr. Scott Morrison, an equine podiatry expert from Rood and Riddle Equine Hospital in Lexington, Kentucky, had a cast applied to the affected foot. “This cast was applied with the goal of starting to help re-align his coffin bone properly in that foot,” said Dr. Dean W. Richardson, chief of surgery at the University of Pennsylvania’s George D. Widener Hospital for Large Animals, where Barbaro has been confined for treatment, since his breakdown in the Preakness Stakes last May.

According to Richardson, radiographs taken on January 8 showed improved alignment of the coffin bone and continued healing of the fractured right hind pastern, and he reported that Barbaro’s comfort on that foot had been good, until the developments on January 9.

At this time, Barbaro is being treated much more aggressively for his discomfort, but is reported to be eating well and is otherwise stable.