First, the demand for milk in the growing cities around the Great Lakes and on the Atlantic coast exceeded the supply from the milk producing areas immediately around the cities. Regional demand for milk continues to drive the dairy industry in the zone around the Great Lakes. As dairy herds have increased in size, year-round feeding of conserved forages to housed livestock has become more common. This practice maximizes production per animal in a system where animal numbers are usually limited by available winter housing. Crop production practices .
Corn is grown for both on farm use and as a cash crop.
Alfalfa may be sown in monoculture or with a perennial grass such as timothy or smooth brome. It is harvested as both hay and silage,with two to four harvests being made each year depending on length of the growing season and age of the stand. Although alfalfa replaced red clover as the primary legume of the region, red clover is still grown on wetter soils and where shorter rotations to corn are needed. Red clover is treated as a biennial, whereas alfalfa is a perennial, typically left in the rotation for 3 to 6 years. Longer lived perennial grasses, such as improved cultivars of reed canarygrass, are sometimes grown without legumes.