Most crops are harvested as food for humans or fodder for livestock. Dent corn is typically cultivated as a row crop grown commercially for grain and fodder. Maize is a major source of both grain feed and fodder for livestock. Presently it is grown on large area as a fodder crop. It provides a green fodder palatable to ruminants. Leaves are extracted as fodder for livestock. Trade was necessary because the Soviet Union's domestic production of fodder crops was severely deficient. The affected crops included cotton, sugarcane, rice, pulses, tobacco and animal fodder. It can be used as pig or cattle fodder. There are two basic types&colon; fodder and forage. Several species of clover are extensively cultivated as fodder plants. Its leaf is also occasionally used as a vegetable and the straw as fodder. It is considered a good fodder for cattle. Grass may also be grown and harvested as animal fodder. The ribs are also used as livestock fodder.