Ruminantia is a taxon within the order Artiodactyla that includes many of the well-known large grazing or browsing mammals: among them cattle, goats, sheep, deer, and antelope. All members of the Ruminantia employ foregut fermentation and are ruminants: they digest food in two steps, chewing and swallowing in the normal way to begin with, and then regurgitating the semidigested cud to rechew it and thus extract the maximum possible food value.