MELBOURNE, AUSTRALIA - SEPTEMBER 24: Kerrin McEvoy riding Bon Aurum wins Race 7, Yulong Park Sir Rupert Clarke Stakes during Melbourne Racing at Caulfield Racecourse on September 24, 2016 in Melbourne, Australia. (Photo by Vince Caligiuri/Getty Images)

Ciaron Maher's Group 1 winning entire Bon Aurum has officially been retired after a failed return to racing last weekend.

The rising six-year-old hadn't raced for 596 days before last Saturday due to ongoing knee issues but after he failed to run out the 1200 metre race, it appears his career on the track is over.

"We took another X-ray of his knee - it's OK but it’s on the decline rather than the other way - so I've recommended to the owners that it might be time to hang up the boots," Maher told

"He's been a tough horse and great horse for the stable and hopefully I might get to train a few by him in the future."

Bon Aurum won the Group 1 Sir Rupert Clarke Stakes back in 2016, a race that was also won by his sire Bon Hoffa in 2007.

He had 16 starts for five wins and earned over half a million dollars in prize money.

The Ken King Thoroughbreds owned entire will now head off to stud to start the next phase of his career as a stallion.