There is a story told about sheepdogs by a woman who owned a pair in in the city. It seemed that she was giving a cocktail party one evening, and as the jollities intensified and the hour grew later the guests suddenly looked about and discovered that they were all crowded together in a neat, tight group in the middle of the spacious living room. The two dogs were lying down panting happily, one of each side of the circle of humans. They had successfully herded the dispersed crowd into a tight knot.

Sheepdogs are slaves. They derive an exquisite pleasure from simply working -- and working very hard. A single border collie, it's said, will do the work of six men. A border collie will herd anything -- cattle, sheep, pigs, small children, Greyhound buses. They possess an ability to communicate with what they're herding in an almost mystical fashion. Border collies are the only dogs whose natural instinct it is to circle out in front of the stock and remain always at twelve o'clock to the herdsman, with stock between dog and handler.

The season for dog shows, as for many other things, is upon us. But even for those who would never dream of watching pampered, pedigreed poodles prance around a show ring, the working-dog trials rank right up there with polo, picnics and country fairs as events not to miss.

To watch a border collie work is much like witnessing a ballet -- dog and sheep in an elaborate pas-de-deux, the handler usually whistling commands from a distance of about 450 yards. Recently, the American Sheepdog Association sponsored a three-day clinic for inexperienced dogs and handlers -- those who will be showing up in trials this season and next.

"Come-by," called a handler in the old Scottish terms still used today, and a small black-and-white bullet shot out to the right, circling around the sheep, dropping to an alert crouch as the sheep moved slowly toward the dog's owner and the clinic teacher. "Way to me," called the handler and the dog headed the sheep off left. "Move up, down, back, come-by, down, down." Back and forth went the sheep moving sometimes slowly, sometimes rapidly as the dog snaked right, left, forward, back, according to the commands. The dog was called off and the sheep headed for a hole in the fence. Immediately another, more experienced, dog was dispatched and shot out to head them off. "Down, Tess," shouted owner Ethel Conad. Tess crouched in the grass holding the sheep in exactly the right place to await the next trainee.

"Right now, she's in complete control of those sheep," Conrad noted. "A lot of people don't realize that. She's a ways from the sheep, but is she weren't right there, those sheep would be back at that fence."

Back in the small ring, three sheep stood panting in the heat as a stiff breeze ruffled the long silky black fur of a dog that lay ready to obey commands. "Move-up," called the handler and the dog sped forward, barking and grabbing at the sheep. "Back! Back! Back!" the handler barked. Again and again, the young dog went after the sheep, which ran wildly around the ring.

"She's been working hogs," the dog's handler later explained. "When you want to move a pig, you got to have a strong dog. I'm trying to get some of that out of her here."

A border collie, explained Conrad, whose sheep and farm it was, loses points for taking hold of (biting) the sheep. In England, dogs are instantly disqualified for biting. "A good dog," she said, "will calmly walk the sheep through the course, taking the minimum amount of time" -- each dog as 12 minutes to complete the course -- "with the minimum of stress on the sheep.

At a trial, the dogs are expected to run a course of 450 yards, through a run and two gates, and into a pen. The handler must stay in one spot, at the end of the course, and may move only to open and close the pen. The more advanced dogs shed the sheep -- separating perhaps two specifically marked sheep from a group of five. They are scored on how well they do the job and on speed.

"A border collie's reward for doing well," Conrad said, "is to allow him to do it again."

The day was picture-book, the setting postcard perfect. The rolling countryside complemented the Blue Ridge rising in the background. The air smelled of lanolin and awaking earth. The mood was warm and jolly. People traded stories about their dogs, explained what was going on, joked and ate.

Of such stuff are sheepdog trials made. It's a day for a picnic in a setting that comes straight out of the ultimate fantasy of country living. It's a day when the talents of a happy slave can be appreciated with no little awe. Shades of James Herriott's Yorkshire.