Racing favourite Admire Rakti (C) walks to the track for the start of the Melbourne Cup horse race in Melbourne, Australia, on November 4, 2014Racing favourite Admire Rakti (C) walks to the track for the start of the Melbourne Cup horse race in Melbourne, Australia, on November 4, 2014 (AFP Photo/Paul Crock)
Melbourne (AFP) - The death of Melbourne Cup favourite Admire Rakti reignited calls Wednesday for a ban on whips as initial autopsy results showed the champion Japanese galloper suffered acute heart failure.
Admire Rakti, a seven-year-old, collapsed and died in his stall after fading badly on the final stretch of Australia's premier race on Monday, won by Germany's Protectionist.
Another runner, Araldo, was put down after injuring a hind leg when spooked by a flag being waved in the crowd as he returned to the mounting yard.
It was the second consecutive year in which there was tragedy in the Melbourne Cup. French mare Verema was put down after snapping a cannon bone in 2013.
The Coalition for the Protection of Racehorses, which says 125 horses died on Australian tracks between August 1 last year and July 31 this year, said horses were being pushed too hard and called for a ban on the use of whips by jockeys.
"We believe that pushing horses beyond their physical limits through use of the whip, and racing horses while under-developed at two years of age, are significant factors as to why horses break down on the racetrack," spokesman Ward Young said.
"We're calling on the racing industry to start running whip-free races and phase out two-year-old racing."
Animal welfare group RSPCA said the deaths were a "stark reminder" of the damage the sport can have on horses.
"Sadly, injury and death are the price some horses pay for our entertainment in a sport that puts intense pressure on animals to perform to the limits of their endurance," it said in a statement.
"This is a tragic outcome for both horses and we expect there to be a full and transparent investigation undertaken into both incidents."
Racing Victoria's chief veterinarian Brian Stewart denied excessive whipping was a factor in Admire Rakti's death.
"The jockey immediately put the whip away and relaxed on the horse to ease distress," he told ABC radio. "There's no question in this case that the whip played any role whatsoever."
The Japanese topweight in the race had been well supported after a storming victory in the Caulfield Cup last month, and was up with the lead for most of the 3,200-metre (two mile) event.
But as it rounded the final bend he was noticeably under pressure. Jockey Zac Purton furiously tried to maintain his position, only to drop back sharply through the field to finish 25 lengths behind the second-last horse.
Stewart on Wednesday told SEN radio that initial autopsy results conducted at the University of Melbourne showed that Admire Rakti suffered from heart failure.
"The diagnosis is that the horse died of acute heart failure as a result of ventricular fibrillation probably, which is a disorganised heart rhythm which happens very, very rarely in human athletes and in horses and is a consequence of the athletic heart and the rapid heart rate during racing," he said.
The full autopsy results are due next week.