The 15-year-old gelding won 23 of his 41 races including the Gold Cup in 2007 and 2009 when he became the first horse to regain it after losing to Denman in 2008.
He also won a record five King George VI Chases and was one of the most successful steeplechasers in recent times with 2.3 million pounds ($3.62 million) in earnings.
Regular jockey Ruby Walsh, who partnered him to 17 of his 23 wins said he had been "very lucky" to ride him.
"He's the horse of my lifetime. I'm very lucky to be the one who got to ride him," he said after Kauto's retirement in 2012.
"He was an amazing horse to ride and an amazing horse to be part of and I loved every minute of riding him."
Owner Clive Smith told the Racing Post: "I am devastated. He looks to have jumped something, and stumbled, we're not really sure, but he injured himself -- and it became obvious it was serious.
"The vets made him comfortable but it became evident that it was serious, and the kindest thing was to euthanise him. It was a horrible moment. He was such a wonderful horse, but he did not suffer."
(Reporting by Mike Collett; editing by Sudipto Ganguly)
Share
