From Will Grant's article in Outside magazine:
A ranch dog’s sensitivity to tone and direction develops from the constant, everyday handling. Barring an injury, which would happen every six months or so, the dogs spend all day, every day with you. It’s a working relationship. The smart ones will be better company and harder workers than a hired man—and drink less alcohol and tear up fewer pickups. The dogs complement the workplace. They’re part of the ranch, and the ranch is part of them.