Trotting officials say a recent cluster of positive tests for elevated carbon dioxide levels in horses does not prove the illegal process known as "milkshaking" is rampant in WA harness racing.
Figures tabled in Parliament revealed seven trainers have been penalised since April last year because their horses returned higher than allowed carbon dioxide levels in blood samples.
The results point to agents such as bicarbonate soda being administered to lift horses' carbon dioxide or TCO2 levels.
Of the trainers disqualified for between six months and three years, three were repeat offenders. But Racing and Wagering WA said the positive results do not necessarily mean deliberate milkshaking was taking place because TCO2 occurs naturally in a horse. It's only once a certain level of TCO2 is exceeded that RWWA investigates and decides whether to punish the trainer.In the wake of recent allegations of race fixing in the thoroughbred racing industry, RWWA has appointed another investigator, barrister Teresa Levy, who has worked in investigative agencies in New Zealand.