The first inquiry into a cobalt irregularity in a Queensland racehorse has been adjourned to allow for further scientific investigation into the effect of the substance in supplements.

Chief steward Alan Reardon adjourned the inquiry on Wednesday until May 20 after taking initial evidence.

Racing Queensland stewards opened the inquiry after the Jamie McConachy-trained Vandalised was found to have a cobalt reading above the acceptable threshold in winning last year's Rockhampton Cup.

McConachy told the inquiry he had no idea how Vandalised, a horse he described as a part of his family, came to race with an excess level of cobalt.

"I knew nothing about cobalt. The first I knew about it was when you rang me," he told Reardon.

However, he said at the direction of a vet, he had treated Vandalised for low red-blood cell levels in the lead-up to the Cup.

"My vet said I needed to boost his red-blood cell count," McConachy said.

McConachy's barrister Matt Tutt wanted more evidence on how cobalt could be accumulated from legal supplements which contained it.

Tutt said it was important for all trainers who administered legal supplements which contained the substance.

"We are not talking about administering illegal black-market cobalt. We are talking about cobalt in legal supplements," he said.

The inquiry heard evidence from Dr Bruce Young from the Racing Science Centre and Professor Paul Mills, a pharmacology expert from the University of Queensland.

Dr Young said Vandalised's original swab had been negative to the normal tests.

However, the sample had been frozen and tested after a cobalt threshold was introduced last year.

The later screening test had shown an irregularity and a further examination was ordered.

Dr Young said the irregularity was confirmed in two other tests, one which showed a cobalt level of 280 micrograms per litre and the other 293 micrograms per litre.

The inquiry heard the threshold established for cobalt was 200 micrograms per litre.

Professor Mills said cobalt helped produce red-blood cells and it had been shown to stimulate a horse's performance.