The State of World Agriculture
What is domestication?

Like with crops, humans have manipulated animals to serve as both a food supply and in other capacities. The goal remains the same today as it was during the development of prehistoric agriculture: "to generate animal products at the highest rate of return for investment." (Smith 49) This is mainly accomplished through selective breeding to emphasize whatever characteristic is most desirable in a certain variety of livestock, for example, when raising cows for beef one would emphasize size whereas when raising them for milk one would emphasize their capacity to produce milk. (Encarta. “Dairy Farming”)

The desirable characteristics animals are bred for reflect in many ways the first benefits domesticated animals provided to those human societies possessing them. Such animals "provided meat, milk products, fertilizer, land transport, leather, military assault vehicles, plow traction, and wool." (Diamond 109) The major animals that were domesticated and became important to the world agriculture were chosen for these qualities. These animals were the cow, sheep, goat, pig, and horse. (Smith 24)