Father and son trainers Lee and Shannon Hope will find out next week whether they face a three-year disqualification over elevated cobalt readings in some of their horses.

The Hopes have pleaded guilty to six charges of inadvertently administering a prohibited substance but are fighting doping charges after three of their horses returned cobalt levels above the threshold of 200 micrograms per litre of urine.

The trainers deny they deliberately administered cobalt for the purpose of affecting the performance of the horses in their respective races.

Counsel for the Hopes told the Racing Appeals and Disciplinary Board they should dismiss the remaining charges because elevated cobalt readings do not mean the trainers were cheating.

While cobalt is naturally occurring in horses, increased levels are believed to boost the numbers of red blood cells allowing oxygen to be carried through the body more easily.

The trainers say they do not know what caused the excess cobalt, which they believe may have come from their feeding and supplements program.

Racing Victoria alleges cobalt was deliberately given to the horses either the day before or the morning they raced.

"The stewards put forward, in their submission, a scenario which borders on the farcical," Robert Stitt, QC, said on Wednesday.

None of the three horses - Windy Citi Bear, Best Suggestion and Choose - won or placed in their races and the suggestion they had been doped for financial advantage was "fanciful," Mr Stitt said in his closing submissions.

"It's not as though there was some great betting scam," he said.

Lee Hope had never been charged in his 54-year career as a trainer, and the duo's good reputation was a factor to consider when determining whether they engaged in cobalt doping.

The evidence before the tribunal was consistent with the inadvertent and unintended administration of cobalt through the Hopes' supplements and feed program, Mr Still said.

But counsel for Racing Victoria stewards argued they were not required to show the Hopes' motives.

"There has been no inquiry into the financial circumstances ... and the reason for that is not relevant," said Jeff Gleeson, QC.

"We do not need to establish motive, simply that the breach has been committed."

"This is an important case for the racing industry in Victoria and is a test case on whether the threshold is enforceable," Mr Gleeson said.

The board has reserved their decision until Monday.