Sydney: Melbourne Cup favourite Admire Rakti died from heart failure resulting from natural causes, an investigation into the Japanese galloper`s death said Monday.
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 November 4, won by Germany`s Protectionist.
Racing Victoria on Monday released the findings of a stewards` and veterinary investigation into the death of the horse which found no trace of drugs or other lethal substances in its body.
It said Admire Rakti died from acute heart failure as a result of an irregular heartbeat, due to natural causes.
"We are of the opinion that Admire Rakti died of acute cardiac failure as a result of a cardiac arrhythmia that can be attributed to natural causes," Racing Victoria`s head of equine welfare and veterinary services Brian Stewart said.
Stewart said uncommon changes in the horse`s kidney were found, but additional analysis by experts determined these could also be attributed to natural causes.
"This death has been categorised as a sudden death which are thankfully very uncommon in Victorian thoroughbred racing with the recorded incidence 0.007 percent of an average 43,500 starts each season," he said.
A review of Admire Rakti`s veterinary and treatment records found nothing which would have rung alarm bells. Like all runners in the Melbourne Cup, the horse was under full-time security surveillance from 24 hours before the race.
A veterinary examination on the morning of the race had also found the animal was fully fit for the 3,200m (two miles) distance.
"We are satisfied that the horse was presented in a fit state free of any substances that could have contributed to its death and unfortunately it has suffered a rare sudden death due to heart failure," chairman of stewards Terry Bailey said.
Admire Rakti was one of two horses to die after the Melbourne Cup with another runner, Araldo, put down after injuring a hind leg when spooked by a flag being waved in the crowd as he returned to the mounting yard.
The deaths reignited calls for a ban on whips amid concerns that horses were being pushed too hard.