A trainer who has previously successfully appealed a conviction for a cobalt offence has been disqualified for 12 months on a separate charge involving the substance.

Rochelle Smith has been granted a stay on the new charges and will appeal.

A stewards' inquiry heard Toowoomba trainer Smith's horse Honest Natalie had cobalt detected in a urine sample taken after it ran at the Sunshine Coast on September 24.

Evidence was taken from Professor Paul Chapman regarding specific gravity of urine (USG) and the effect it has on cobalt readings.

The inquiry also heard evidence from Dr Karen Caldwell. acting manager Veterinary Services at the QRIC Racing Science Centre and Samantha Nelis, acting manager Analytical Services at the same organisation.

Smith's lawyer Matt Tutt made submissions in response, specifically the evidence given by Professor Chapman regarding the USG and the effect that dehydration can have on cobalt readings.

But stewards found when considering the USG submissions by Professor Chapman, that evidence given by Dr Caldwell and Ms Nelis was pertinent in that the process by which the threshold (100ug/L) was established took account of variations in specific gravity.

After considering the evidence stewards charged Smith with bringing a horse to race with a prohibited substance, cobalt, in its system.

Smith pleaded not guilty but stewards found otherwise and disqualified her for 12 months to end in February next year.

In September 2016, Smith successfully appealed a 12-month ban on cobalt charges involving two of her horses.