The early milk consumption on the Tibetan Plateau.

In contrast to primary animal products(meat,hide,blood,and bone)which can be extracted only once in the lifetime of an ani-mal,secondary animal products are defined as those which can be exploited without slaughtering animals,for example milk,wool,power and dung.In the secondary products revolution model,the appearance of secondary animal products created a new type of human-animal relationship,increased the productivity and mobil-ity of Neolithic farmers,and eventually facilitated the rise of com-plex societies in the Near East[1].