Shannon Hope has been told he carries the burden for ruining his father's unblemished half century in racing.

Shannon Hope has been disqualified for five years and 64-year-old Lee Hope for three years for intentionally administering cobalt to affect the performance of three of their racehorses.

Lee Hope had previously held an untarnished record over 50 years as a licensed person in racing and his son over 25 years.

The Racing Appeals and Disciplinary Board deemed Shannon Hope to be more culpable as he was responsible for the feeding, supplementation and medication regime of the three horses at his Seymour stables.

"Lee Hope was aware that cobalt was being used but his role was inactive whereas Shannon played an active role and carries the burden of moral culpability for what occurred," Judge Russell Lewis said on Tuesday.

The Hopes and their legal team have not said if they will appeal the penalty, the first disqualification for cobalt use in Victorian thoroughbred racing.

The Hopes faced a minimum three-year disqualification after being found guilty of intentionally administering cobalt to affect the performance of Windy Citi Bear, Best Suggestion and Choose in races last year.

Their legal counsel Robert Stitt QC had asked for a fine for at least Lee Hope but the RAD Board did not accept special circumstances existed to mitigate the mandatory disqualification.

The tribunal last week found both trainers knew more about cobalt than they admitted and agreed with racing stewards that cobalt exceeding the allowed threshold and higher than that declared by the Hopes was administered on or before race day.

As the first cobalt inquiry in Victorian thoroughbred racing, the Hopes' case was viewed as a test of whether the declared cobalt raceday threshold of 200 micrograms per litre of urine was enforceable.

Three other Victorian trainers - Danny O'Brien, Mark Kavanagh and Peter Moody - and veterinarian Dr Tom Brennan also face charges over elevated cobalt readings with their cases to be heard before Christmas.

NSW stewards have disqualified Brennan for six years and Mark Kavanagh's son Sam for nine years and three months for cobalt offences but both are appealing.

Newcastle trainer Darren Smith in August lost an appeal against a 15-year disqualification for cobalt offences.

The Hopes' $50,000 share of prize money, which had been held in trust by stewards pending the outcome of the case, will be returned to them.