Maryland standardbred horsemen will ask the Harness Racing Board of the Maryland Racing Commission to allow them to use the diuretic Lasix to the same limited degree as now permitted with thoroughbred racehorses, trainer-driver Tony Kurtz said yesterday.

Kurtz, a spokesman for the horsemen, said more than 90 have signed a petition seeking a change in rules that currently do not permit a harness horse to race with any medication.

The thoroughbred rules allow limited use of Lasix; the rule was significantly liberalized after owners of Desert Wine went to court and got an order allowing them to race their horse on Lasix in the Preakness.

Until then, a thoroughbred could race with Lasix only if the state veterinarian detected the horse bleeding while racing or coming off the track. Under the relaxed rules, any two veterinarians can certify a horse as a bleeder if they observe him bleeding anytime during a day.

The horse's name is then put on a bleeders list and he is eligible to race on Lasix, administered by a state vet in a detention barn area prior to the race.

The latest effort by standardbred horsemen comes in the wake of five suspensions last week by the state judges at Freestate Raceway against trainers whose horses tested positive for the diuretics Bumetanide and Ethcrynic acid. Until recently, testing labs had been unable to identify these diuretics.

Trainers Norwood Truitt, Steve Swann, Richard Kent, Millard Jennings and John Lare received 30-day full suspensions. Only Lare is appealing.

"They were trying to replace Lasix with something else," Kurtz said. "Almost all of us have a bleeder in our barns. But they evidently found a test to detect them at Brandywine (in Delaware) and told the (lab) boys down here about it. I know if I had a bleeder I probably would have been caught. We definitely need some kind of (Lasix) rule.

"We have at least 60 horses here on the grounds (at Freestate) that--I won't say can't race--but can't race competitively in their class without Lasix."

Now that there are means for detecting Bumetanide and Ethcrynic acid, John Knight, presiding state judge at Freestate, said recently he did not expect any more positive tests for those diuretics. He said last week that all positive tests came back from races run Aug. 10-13.

"I don't think it's a problem," Knight said. "As soon as it is detected, we won't have any more of it . . . Horses get treated for soreness just like any other athlete is treated. Drugs come on the market and people use them to get their horses to race well. The lab gets a procedure to detect those drugs; it hits at one time and then it's gone."

The next meeting of the harness board is scheduled Aug. 31.