U.S. and Canada major exporters, China a major producer but for domestic consumption only. Sheep can live in hillier and drier conditions than cattle. Livestock ranching is extensive, i.e., requires a lot of land. Carrying capacity is the measure of what the land will support. So ranches tend to be large.
Dry grassland is good for ranching, but unsuited for farming.
Spread of irrigation is reducing ranching in U.S. because farming offers higher productivity per acre. Discuss, and give examples. In places like Iowa the carrying capacity of a ranch may be as low as 5 acres per steer, while in the Southwest it can be as high as 100 acres per steer. Yet cattle are raised more in the southwest than in Iowa.