Silage is fermented, high-moisture stored fodder which can be fed to cattle, sheep and other such ruminants (cud-chewing animals)[1] or used as a biofuel feedstock for anaerobic digesters. It is fermented and stored in a process called ensilage, ensiling or silaging, and is usually made from grass crops, including maize, sorghum or other cereals, using the entire green plant (not just the grain). Silage can be made from many field crops, and special terms may be used depending on type (oatlage for oats, haylage for alfalfa – but see below for the different British use of the term haylage).[2]

Silage is made either by placing cut green vegetation in a silo or pit, by piling it in a large heap and compressing it down so as to leave as little oxygen as possible and then covering it with a plastic sheet, or by wrapping large round bales tightly in plastic film.