One Western convention is that cattlemen and sheepherders do not mix. Cowboys look with contempt on sheep men, and range wars break out when sheep come into cattle country. Sheep just seem unnatural intruders on the cattle range. They devour all the range grass, making the range worthless for future cattle raising. One of John Ford’s earliest films, The Gun Packer (1919), is based on this rivalry. By 1967 the convention was so established that Andrew V. McLagen could direct a comic Western starring Doris Day, The Ballad of Josie, in which a female sheepherder brings her sheep onto the range and organizes women in the town to make sheep acceptable.
Historical Dictionary of Westerns in Cinema. Paul Varner. 2012.