High profile trainers Mark Kavanagh and Danny O'Brien have been banned for three years and four years respectively for administering cobalt to horses for performance-enhancing purposes.

Both Kavanagh and O'Brien faced mandatory minimum three-year bans after being found guilty of doping by the Racing and Appeals Disciplinary Board (RAD) in December.

Veterinarian Dr Tom Brennan was banned for five years.

Both trainers are expected to appeal against the decision at the Victorian Civil and Administrative Tribunal (VCAT).