The ruling by the Maryland thoroughbred racing commission slapping a partial ban on the use of the drugs Butazolidin and Lasix on state tracks has brought severe criticism from some area horsemen.

John DiNatale, trainer of Gasp, the winner of several feature races at Pimlico, said today, "The rule regarding Lasix only being allowed to horses seen bleeding after a race by the track veterinarian is going to work hardship on those horsemen with bleeders. The rule says that the horse must be brought to the detention barn five hours before its race and must be given the Lasix by a licensed practicing veterinarian before the five-hour deadline.

"Just imagine what that means to a horseman stabled at Pimlico with a horse in the first race at Bowie," said DiNatale. "He will have to leave his stable at 7 in the morning to satisfy the new rules. That means his entire day is shot to accommodate that one horse. That's not fair."

Fendall M. Clagett, area representative of the Horsemen's Benevolent and Protective Association, said, "The five-hour prerace rule regarding Lasix is unfair. It will mean hardship for horsemen.And the 24-hour ban on Bute is misleading. The tolerable amounts in the blood of horses is 2 micrograms per milliliter, which is such a small tolerance that we can't administer Bute to our horses within 72 hours and still feel we've obeyed the rules. I predict a hugh exodus to other tracks."

As initially proposed by the commission, prerace tests of the horses would have allowed no traces of Bute. That provision was amended yesterday to allow the 2 micrograms per milliliter, but horsemen say that still effectively bans the use of the drug for 24 hours before a race.

The commission also voted to change the method of testing horses from urine samples to blood samples.