Grass
It is one of the richest and most balanced feeds for ruminants and contains 80% water. The remaining 20% are minerals (calcium, phosphorus, sodium, potassium, magnesium), vitamins, proteins, carbohydrates, and a little fat. Dried grass is called hay and is used to feed livestock, especially in late autumn and winter. Permanent grassland occupies 37% of French agricultural land, the equivalent of 11 million hectares.
Maize
Hay can be replaced by maize fodder, which provides more energy and is highly digestible. It is the staple feed for dairy cows on about 90% of farms in winter. If left in the open air, the fodder will dry out and lose its nutritional value. Silage is used to remedy this: it is preserved by fermentation in silos, where it protected from the oxygen in the air.
Cake
Feed supplements are provided in the form of oilcake (the part of the plant that remains after pressing) made from soya, peanuts, or oilseeds. The daily portion for a dairy cow is between 500 g to 2kg
Straw
Straw is made of dried stem of grasses grown for human consumption (wheat, barley, etc.) which are left over after the grain has been harvested. Its nutritional value is quite poor, so it is mainly used as bedding.