'Career Canines': Dog from a rich pedigree was born to herd sheep

— -- In what appears like controlled chaos, Rob, a border collie, makes snap judgments and relies on instinct and whistle commands when herding sheep. He comes from a long pedigree of Scottish herding dogs, which were bred for this work.

Jack and Kathy Knox of Ettrich Kennels in Butler, Missouri, have found their life's work managing the complex relationship between sheep and canine. "Sheep are prey animals. The dogs are a predator, basically. You're working with two separate instincts that you're wanting to join into a partnership," Kathy Knox told ABC News. "A communication where the sheep aren't panicking because the dog is there. The sheep is saying, "Where do you want me to go?" and letting the dog take them that way."

When picking a dog for their farm, the Knox family looks for a blend of traits. They watch for the way the dog approaches sheep, its use of eye contact to maneuver the them and how it maintains balance in order to control their position. "Old shepherds used to say a good dog can steer a sheep on the end of his nose," Jack Knox said, "What they meant was, if the sheep bends, he [the dog] just needs to bend his head, and the sheep will turn onto the line again. That's the dog and a perfect balance."

The most demanding time on the farm comes during lambing season. Over several weeks, hundreds of ewes are giving birth at a pace that it is difficult to keep up with. Kathy Knox relies on her dog Rob to separate the flock to tend to the newborns. Over years of working with dogs in the pastures, she continues to be impressed by their drive to work. "There's no bottom to them. It doesn't matter what the weather is. It doesn't matter what time of day," she said. "My Rob dog ... some of these days, he's worked all day long. Sheep have been running at him from every angle. He's always like, 'Well, let's go. What's the next job?'"