Coneygree, who won the Cheltenham showpiece in 2015, was having only the 18th race of an injury-curtailed but glorious career in Saturday's Keltbray Swinley Chase.
He led until the 14th obstacle under Nico de Boinville, reviving final memories of their greatest triumph together nearly four years ago – but the exertions told as Coneygree was eventually pulled up two from home .
“Wear and tear and injuries have just got the better of him now, so we'll call it a day,” trainer Mark Bradstock's wife Sara told ITV Racing.
“I'm only sad because he (still) loves it. He still thinks he's a racehorse.
“I think what happens now is that it would be fine (to run him) on the perfect bit of ground and on the perfect day – but you can't risk hurting him for that. “
Bradstock hopes that home-bred Coneygree will continue to have an active career away from the track.
“He will come home, and we will make sure he is okay – then we will do something with him,” she said.
“We might do a bit of the Retraining Of Racehorses program with him. There is a good home for him here – and he will never leave my side.”