Rules. According to the new national trademark regulations, the first layer of cowhide is unified as cowhide, sheepskin is unified as sheepskin, and the second layer is cowhide transfer leather. Sheepskin is the skin of goat or sheep in Bovine family. The skin of goat or sheep contains water, protein, fat and inorganic substances, and the latter two contents are very small. The protein extract that constitutes the epidermis is mainly keratin; Dermal is mainly composed of collagen and reticulin, in addition to elastin, albumin, globulin and mucin.