DEL MAR, Calif. - Mad for Plaid, a maiden-claimer trained by Peter Miller, became the first horse euthanized at Del Mar this summer when she broke her left front sesamoids following a workout here on Sunday morning, and a delay in reaching and treating the stricken animal infuriated Joe Harper, the track's president, who said a review would be undertaken.\nMad for Plaid was working in company, and broke down just after passing the finish line. But there was no outrider near the incident, a warning horn never sounded, and an ambulance did not arrive on the scene until several agonizing minutes passed. By the time the track was reopened for training, 25 minutes had elapsed.\n"There's no excuse for this," said Harper, who is at the track each morning. "Everybody's pointing fingers right now. We'll get everybody in a room and see where the fingers point. We want to make sure this doesn't take so long."\nThe track's clockers said they had no radio with which to reach an outrider, even though the track has been open for training for a week; the meet begins on Wednesday. The clockers did not know why the horn did not sound when an attempt was made to activate it. Harper said there are four outriders on the track, and each is supposed to be positioned a quarter-mile from one another.\nMad for Plaid at one point got away from her handlers and tried to escape, but she could not get far on her grotesquely injured left front leg. After being caught, she was given a heavy sedative on the track by a veterinarian, fell prone, then was pulled into the ambulance with a winch. The ambulance was an old trailer pulled by a tractor. The two high-tech ambulances on this circuit are currently at Hollywood Park, which closes on Sunday. Those ambulances will be at Del Mar no later than Wednesday.\n"This is unreal," Steve Kenly, the owner of Mad for Plaid, said during the delay. "This is like the Dark Ages."