LEXINGTON, Ky. (AP) - Rachel Alexandra is in serious condition while recovering from surgery related to complications involving the birth of her filly.

The 2009 Horse of the Year had surgery Wednesday to repair an area of bruising in her small colon, which was injured during foaling, according to Stonestreet Farm.

"We are solely focused on making sure Rachel is as comfortable as possible," her owner Barbara Banke said. "She is showing the same strength and courage now that she demonstrated on the track. Our hearts are broken by this turn of events and I can only ask that you send your thoughts and prayers to Rachel now."

Doctors at Rood and Riddle Equine Clinic say a full prognosis for Rachel Alexandra can't be determined at this time.

Rachel Alexandra's filly by Bernardini was born Tuesday weighing 140 pounds. She is healthy and has returned to Stonestreet Farm where she will be tended by a nurse mare.

In January 2012, Rachel Alexandra gave birth to a colt by two-time Horse of the Year Curlin.