The derby-winner, Kyle Calvin, was owned and trained by Marie Field, wife of the former chief executive of the Irish Greyhound Board, Michael Field.
The dog was among six dogs who tested positive at the national meeting in Clonmel earlier this year.
Ms Field was fined €6,000 and forced to forfeit the €35,000 prize money.
The winnings now go to Noreen McManus, whose dog, With Grim Intent was runner-up in the coursing final derby last February.
Kyle Calvin has also been banned from breeding, coursing, and racing for five months.
Mr and Mrs Field, of Patrickswell, Co Limerick, are well known in the greyhound industry. Mr Field, who is said to be “very upset” at the result of the doping test, was chief executive of the Irish Greyhound Board from 1997 to 2003.
CEO of the Irish Coursing Club, DJ Histon, who announced the decision, said there had been no appeal by the Fields or the other five dog owners.
An industry source said: “As far as I know he (Mr Field) is very upset by it.
“Within the last number of years that (illegal) substance was not a prohibited substance.”
“He’s gone to ground a bit, but that’s nearly 12 months ago. It’s a disappointment for him personally,” the source added.
The Fields could not be reached for comment, but Mr Field is expected to make a statement in the coming days.