Claiborne Farm’s highly successful stallion Flatter has died. He was euthanized May 9 due to the infirmities of old age, the farm reported May 10. The stallion was 23.

The son of A.P. Indy was a second-generation homebred for Claiborne and prominent owner/breeder Adele Dilschneider out of the Mr. Prospector daughter Praise, making him a full brother to grade 2 winner and notable sire Congrats .
After finishing fourth on debut, Flatter rolled off a four-race winning streak at Churchill Downs, Arlington International Racecourse, and Turfway Park, before finishing third in the Washington Park Handicap (G2). The Steve Penrod trainee was retired after that effort with four wins in six starts.
Flatter retired to stud at Claiborne in 2004. He has sired 16 crops of racing age that have yielded 692 winners and more than $84.1 million in progeny earnings. He has sired 59 black-type stakes winners worldwide, which include 21 graded/group winners.