WASHINGTON - Dairy farming became widespread in Britain as early as the new stone age — around 4,000 B.C. — a team of researchers at England's University of Bristol reports.Mark Copley, an archaeological chemist, said evidence of milk fats was found on broken pieces of pottery at several ancient sites in southern England.Using new methods of analysis, scientists have learned to differentiate between ancient residue from milk fat and other fats and oils in recent years, Copley and his team report in Proceedings of the National Academy of Science.Their findings provide evidence of "the earliest farming communities in Britain, though...