BLACKSBURG, Va., Aug. 25 -- Virginia Polytechnic Institute and State University issued the following news release:

Danika does circus tricks. Ask her owner, Carolyn Steppe, and she'll tell you the mare has never had a bad moment in her life - until, that is, a mass developed on the inside of her leg that grew to the size of a tennis ball, threatening to end her show career.

"She is a very social and vocal girl and loves to entertain her humans with a handful of circus tricks," Steppe said. "She never has a bad moment and is the happiest horse I've ever known - definitely my heart horse."

The journey for Danika and Steppe would lead to the Marion duPont Scott Equine Medical Center in Leesburg, one of three teaching hospitals and animal he...