Jack Kaenel, 15-year-old apprentice jockey who was suspended by the stewards at Pimlico Race Track Wednesday for lying about his age, underwent an emergency appendectomy in an Ohio hospital Friday night, hospital official confirmed yesterday.

Pat Eltringham, nursing supervisor at East Liverpool City hospital said Kaenel was brought in by his parents Dale and Kathy Kaenel, late Friday and was operated on immediately. Eltringham said Kaenel is in satisfactory condition in the pediatrics ward of the hospital and should be released in five to seven days barring any postsurgery complications.

"The operation went just fine," Eltringham said. "There were no problems at all."

The emergency surgery came at the end of a difficult week for Kaenel. It began with Kaenel as the leading jockey at the Pimlico meeting with 37 winners. Kaenel was suspended after admitting to Pimlico officials that he had falsified a birth certificate to make himself 16, the minimum riding age in Maryland.

Kaenel and his parents, who had been living in a trailer on a farm outside Baltimore while Kaenel rode at Pimlico, had left the baltimore area Wednesday, to visit friends at Waterford Park in West Virginia. The track, just across the state line from East Liverpool, has been dark since Tuesday because of a horseman's strike.

Kaenel's parents reportedly were with him at the hospital yesterday but could not be reached for comment.