Almoonqith had no pre-existing condition that would have caused him to break down in the Sydney Cup.
Racing NSW stewards held an inquiry on Monday into the catastrophic leg injury the horse suffered in the Cup on April 8, causing the race to be abandoned and Almoonqith euthanised.
Trainer David Hayes told stewards Almoonqith had pleased the stable in the lead-up to the race and had shown no signs of any lameness.
The post-mortem urine sample taken from Almoonqith was negative to all prohibited substances other than pentobarbitone and xylazine, the drugs used to euthanise the horse.
The Sydney Cup was re-run on Saturday and won by Godolphin's English visitor Polarisation who also crossed the line first in the no-race.