Dolly was looking good. Her honey-brown hide had been trimmed and brushed. Every whisker around her moist nose was carefully clipped. Her tail was fluffy, her hooves shiny with mineral oil and buffing.

Jason Haines, her owner from Damascus, wasn't looking bad, either. He was dressed in spotless whites, and a small white cap with his contest number on it was firmly set on his curly golden head. His cheeks were flushed. It was almost 10 minutes to show time, prizes were about to be given out, and he and his calf were going in this together.

At age 10, Jason is no stranger to county fairs or contests, although this was his first time ever exhibiting an animal. At last year's Montgomery County Fair he walked away with several 4-H blue ribbons in the canning category. This year, he got the award for the junior with the most blue ribbons in canning.

But strange things happen even to the experienced when winning is a passion: A few minutes before the Open Jersey Senior Heifer Calf category opened for judging one day this week, the boy went silent and numb with apprehension. He had to listen to questions repeated twice before answering in throaty monosyllables. His soul was elsewhere.

There was a tugging at his sleeve. "Jason!" said an even more breathless voice. It came from a pale, six-year-old boy. "Look!" and Jim Kelpy held up for all to see the second-prize red ribbon he had just won for Dusty, his bull calf.

At the 35th Annual Montgomery County Fair, running through Saturday at Gaithersburg, there are two kinds of people: those who go because they have something to do there, and those who go because they don't.

Those who do are the owners of more than 3,000 animals entered for judging. Particularly devoted are about 250 members of the county's 4-H clubs, who are spending the week camped out among their animals. The more successful go the full circuit from Gaithersburg to the state fair next week, and from there maybe even to the national animal championships.

Those who come to idle are town youth, sharp-edged young slickers who crowd the fair's extensive carnival grounds in the evening, promenading with their halter tops and tattoos. They visit the animal exhibits only to hoot at a pig or two, ignore the cows and gaze with some fascination at the respective undersides of billy and nanny goats.

The 4-H youngsters want nothing to do with these frivolous fireflies. Every second of their day is devoted to showing their animals and winning prizes. They are hardworking, well-behaved and thrifty with their words and money.

Others might consider the $25 first-prize money for any given category a negligible amount. Not 4-Hers. "It doesn't quite add up to what you invest feeding your animal," says Patti Grossman, who breeds champion goats, "but it helps."

An overwhelming sense of purposefulness pervades the exhibition grounds in the mornings, before the townfolk arrive smelling of perfume and cigarettes. In every barn a few adults and an army of adolescents wield shears, clippers, hoses, brushes and sprays on scores of reluctant but patient mammals in preparation for The Big Moment.

By late Tuesday morning, it was already a little too much for Creek, the 10-month-old calf owned by 16-year-old Walter Stottlemeyer. Walter, a town youth who spends his summers at his friend Bobby Johnson's farm in Dickerson, was preparing for his first exhibition, scheduled for today. When the electric whirr of Johnson's clipping shears approached Creek's forehead, she rolled her eyes and balked.

For a visitor, Stottlemeyer enumerated the fine points of bovine beauty. "Her back should be real flat like an ironing board . . . and her legs should be pointing all four in the same direction . . . she ain't got the greatest legs, I guess."

The teen-agers in the 4-H dairy cattle barn stayed next to the stalls even after they finished grooming their animals. "We don't want them rolling around in the dung," a lanky teen-ager explained as he went after it with a shovel.

As shadows lengthened and carnival lights glittered, an occasional urbanite stopped to gawk ("Look honey! There's a bull!"), but inside the barns the world of the farm prevailed. By 10 p.m., when the fair games were in full swing, the 4-H boys were spreading blankets out on the hay for the night while the girls went to their families' vans in the parking lot.

The mothers are the great unsung presence of the 4-H world. They raise their children for competition and discipline.

By 8:30 Wednesday morning, Hanna Blair was already nudging her daughter, Keri, 10, to the metal washing stand at the end of the sheep barn. "What's Keri gonna do?" asked a friend. "Wash her sheep," the mother said firmly. "But she already did!" a visitor protested. "Not to my satisfaction."

Hanna Blair then helped a neighbor's child hoist a recalcitrant sheep up on the washing stand, while another woman gave pointers to three girls fussing over a curly cheviot sheep with hair scissors and talcum powder.

Back in the cattle barn Jason Haines' mother was providing badly needed moral support. "Remember, this is an open," she said. The "opens" are exhibitions of both 4-H animals and adult-owned ones, commercially and privately bred. Children Jason's age enter for the experience rather than for the chance of a prize.

As Jason nudged and tugged his cow into the exhibition arena, Dolly followed more willingly than most, obviously as fond of the boy as he was of her.

Jason watched breathlessly, open-mouthed, as the judge, a stern-faced man from a large Jersey farm in Ohio, scrutinized each heifer in turn. But Judge Gene Wedertz' eyes were not on the sweet-eyed Dolly. From the beginning he had focused on a strapping animal from the Silver Maple Jersey Farm, a commercial dairy enterprise, and from the beginning, Dolly was destined to place last.

There is no consolation for hopes dashed from such heights as Jason's heart, but his mother tried. "I'm sure we'll have better luck at the 4-H showing on Friday," she said. He did not answer.

Back in the barn, Jim Kelpy had recovered his breath and normal coloring after the stunning impact of winning his red ribbon. He sat dreamily next to Dusty, who was sprawled inelegantly in the hay. Someone asked if he was going to watch his brother in the next exhibit. "No," he answered softly. "I'm just going to sit here and pat my calf."