Maize silage is a maize crop cut and ensiled in a stack or bunker. It is commonly used as a supplement to pasture in situations where cows would otherwise be underfed. Maize silage is a high quality forage supplement. However, it is particularly low in sodium, calcium and phosphorus, and can be used as an effective carrier to supplement cows with magnesium. Maize silage is full of soluble carbohydrates which while being a great food for cows, is also loved by spoilage bugs, such as yeasts and mould. The aim of the ensiling process is to get air out of the stack and keep it out until maize silage is ready to be fed.