Silage vs haylage has been an ongoing conversation for decades with farmers. Silage is a fermented food, used for sheep, cows, and other cud-chewing animals and comes from grass, maize, cereals, sorghum, and other crops. Silage is sometimes named after the forage it is made from, for example, oat silage is sometimes called oatlage. Initially, the vegetation is stored in a silo in a huge pile, compressed to remove as much oxygen as possible, and then covered with plastic.