An investigation published Tuesday into the extent of doping in Ireland's thriving greyhound racing circuit imposed penalties on eight dog owners, the largest-scale punishment since the sport was rocked last year by a drugs-cheating scandal.

The report from the government-appointed Control Committee imposed fines ranging from $280 to $2,800 on the eight owners, who were found guilty of feeding their dogs a range of performance-enhancing drugs, including cocaine.

Some owners also were ordered to hand their prize money for particular races to the owners of No. 2 finishers. All received warnings they could be banned from the sport if they were caught again. Most of those identified live in the British territory of Northern Ireland.

Greyhound racing is big business in the Republic of Ireland, a gambling-friendly nation where crowds bet twice weekly on dog races at more than 20 tracks nationwide. The Irish Greyhound Board says more than $70 million in bets were placed last year through racetrack bookmakers, while race winners collected more than $17 million.

But the rising financial rewards have fueled suspicions of drug-enhanced performances. In February 2006 the board came under fire for allegedly trying to cover up evidence that some trainers were feeding dogs EPO, the same drug that has tarnished the Tour de France. Two trainers were fined $1,400 at the time.

The government established an independent committee following widespread accusations that the greyhound industry was not adequately policing itself. The committee, which includes a lawyer and a veterinarian, handed down its first punishments Tuesday.

Irish Greyhound Board chief executive Adrian Neilan said he welcomed the punishments as likely to deter other cheaters. He said more than 5,500 blood samples were taken from dogs taking part in races last year.

Neilan said his board "will provide all necessary assistance to ensure the highest level of integrity in the Irish greyhound industry."