Dairy farming in the seventy years before World War I was a picture of contrasts. On the one hand, areas of heavy concentration were being developed. Zones around cities became devoted to fluid-milk production and underwent modernization prescribed by city milk ordinances. Other areas became devoted to butter production. In Wisconsin thousands of cheese factories opened, some specializing in “foreign” varieties, such as Swiss and Limburger. By 1919 Wisconsin had overtaken New York as the top dairy-production state, with the vast majority of its milk going into manufactured products, mostly cheese. In many states, progressive farmers banded together into state dairy associations, which promoted scientific dairying. This meant keeping records of production by particular cows, culling low-producing animals, being careful with cleanliness, and sometimes adopting breeds known for high-volume milk production, particularly Holsteins.