A winsome but hardworking Hungarian herding dog, a swift and ancient African hound and a playful, fur-free terrier are about to get their first shot at the most famous U.S. canine championship. The pumi, the sloughi and the American hairless terrier will be newcomers at next month's Westminster Kennel Club dog show, competing among as many as 202 breeds and varieties for the coveted best in show award.