How does the Scotch half-breed treat the dogs and why is this important to Buck's future?

The Scotch half breed treats the sled dogs fairly even though he pushes them extremely hard. He comes into Buck's life after Francois and Perrault depart the story. The author may have purposely unnamed this character to add to the idea that Buck's time with him was characterized as "business-like." Buck did the work. That's all there was for him to do. No time to become emotionally involved with his owner. In a sense, this experience served Buck well in that it taught him to work hard. And in doing so, the "reward" would be satisfaction that the work was done. That's all. Task + hard work = task finished. As a consequence, it left Buck longing for more out of his life. Could a demanding master also be a loving master? That question would be answered when John Thornton subsequently became Buck's master.