Champion sire Flying Spur has been retired from the stallion roster at Arrowfield Stud at the age of 20 due to fertility issues.
Arrowfield boss John Messara said the son of Danehill had experienced a sudden and irreversible decline in fertility this season.
"Flying Spur is a very special horse for us, as we bred him, raced him in partnership and have been proud to stand him since 1997," Messara said.
"He is one of the pillars upon which Arrowfield Stud has been built and his home will be here with us for the rest of his life."
Flying Spur was trained by Lee Freedman to win the 1995 Golden Slipper and added the Australian Guineas and All Aged Stakes to his Group One tally in 1996 and was retired to stud later that year.
His first crop of two-year-olds appeared in 1999 and he ended the 1999-2000 season as Australia's champion first season sire.
He won the general sires premiership in 2007, the year his daughter Forensics won the Golden Slipper.
To date Flying Spur has sired 86 stakes winners, 12 at Group One level.
His Group One winning son Casino Prince was last season's champion first season sire and his progeny includes All Too Hard, Saturday's winner of the Caulfield Guineas.