Barbaro had another section of damaged tissue removed from his left hind foot Saturday, and a cast was placed back on his right hind leg for additional support.

The Kentucky Derby winner had a significant setback this week in his recovery from laminitis - a painful, often fatal disease - in his left hind foot. Chief surgeon Dean Richardson removed more of the hoof Saturday.

"The left hind deep digital flexor tendon was cut to help decrease the pull on the coffin bone by that tendon," Richardson said in an update issued by the University of Pennsylvania's New Bolton Center.

"This was previously done in July, but the tendon had healed and was pulling on the coffin bone, contributing to the malalignment of the coffin bone."

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