Ulla Salzgeber’s Olympic dressage horse, Rusty — the Valegro of his day — has been put to sleep at the age of 25.

The pair were one of Germany’s most successful and popular combinations, winning Olympic team gold and indiviual bronze in Sydney 2000 (pictured) and team gold and individual silver in Athens in 2004.

They were European champions in 2001 and 2003.

The Latvian warmblood, by Rebuss, was retired after the Athens Olympics and had been enjoying life on a retirement yard in Hungary. But the decision to euthanase him was taken last week, after he lay down in his field and was unable to get up.

Ulla Salzgeber paid tribute to her “best and most loyal friend and partner”.

She added: “He spent his retirement in the best care, together with his best pony friend, Motte.

“It’s good to know that he had many lovely years… after the showring.”

Among their many achievements were World Cup titles in 2001 and 2002 and team gold and individual bronze at the World Equestrian Games (WEG) in Rome in 2000 — placings they repeated at WEG 2002, in Jerez, Spain.

But they hit a low point the following year, when Rusty tested positive for higher-than-permitted levels of testosterone at the 2003 World Cup final.

Ulla suffered a heart-stopping moment at the Sydney Olympics, when her music stopped playing during the freestyle finals, but they carried on to take individual bronze.

Rusty’s dramatic freestyle music — from Carmina Burana, the music used in the film The Omen —was never changed and his kur became known for its immaculate pirouettes and tempi changes.

Earlier this year, two clones of Rusty were unveiled. The yearlings — one in the USA and one in France — are being raised by the cloning specialist Cryozootech to become stallions. But is unlikely the exact feeling he gave will ever be replicated.

“I still think about this unique feeling that Rusty has given me in so many tests,” said Ulla.

“He will always be special to me.”