Harbinger, recently named the highest rate horse in the world by the World Thoroughbred Rankings, was officially retired on Monday, two days after having suffered a condylar fracture to his left front cannon bone in a workout at Newmarket, England.A 4&#45;year&#45;old&#45;trained son of Dansili trained by Michael Stoute, Harbinger won the 1 1/2&#45;mile, Group 1 King George VI and Queen Elizabeth Stakes at Ascot by a record 11 lengths in his final start on July 24, a performance that had made him the favorite for the Prix de l&rsquo;Arc de Triomphe.Harry Herbert, representing Harbinger&rsquo;s owners at Highclere Thoroughbred Racing, issued a statement saying, &ldquo;It is with regret that it has been decided to retire Harbinger from racing. We are pleased to report that thankfully the horse is recovering well. The decision to retire Harbinger is based on the welfare of the horse, which is paramount to all.&rdquo;Harbinger underwent surgery to repair his broken leg at the Newmarket Equine Hospital on Saturday night. The winner last year of the 1 1/2&#45;mile, Group 3 Gordon Stakes at Goodwood, he had won all four of his starts this year, preceding the King George with victories in the 1 1/2&#45;mile, Group 3 John Porter Stakes at Newbury, the 1 5/8&#45;mile, 61&#45;yard, Group 3 Ormonde Stakes at Chester, and the 1 1/2&#45;mile, Group 2 Hardwicke Stakes at Royal Ascot. Bred in Great Britain by Mrs A.K.H. Ooi, Harbinger won 6 of his 9 lifetime starts for earnings of $1,191,289.