Herbivore breeding is intimately linked to its territory. It is indeed the soil that produces a large part of the animals’ food, and in return the animals help to maintain and enhance the soil. It is therefore necessary to cultivate this essential interdependence for the farmer and the environment, which varies from one region to another.
In the USA, ruminants are mostly raised in either mixed (crop and grassland) or grassland (grassland) systems. These systems allow the animals to be fed almost entirely with the farm’s own fodder and cereals. On average, it is considered that for each cow, there is one hectare of land nearby that provides the animal’s feed while recycling its manure. Spreading animal manure on the farm has a double advantage: it enriches the soil with organic matter and replaces chemical fertilizers. In addition, these quasi-autonomous systems avoid importing or transporting fodder or cereals and allow for the maintenance of local agricultural biodiversity and a varied crop rotation.
The place of grass
Herbivore breeding (cattle, sheep, goats, horses) is practised throughout America. It is mainly located in the “less-favoured areas” where grazing remains the dominant method of exploitation. Indeed, herbivores, and in particular ruminants with four stomachs, are by nature capable of digesting grass that grows on non-cultivable land, which they transform into milk and meat.
In France, grass makes up an average of 60% of the ration for cattle (see: cattle feed), with this proportion varying according to the season and region, depending on soil and climate conditions. In grassland regions where grass grows well all year round, this proportion rises to 80 – 90%.
In other regions with drier summers or small farm areas, grass can be supplemented or even partially replaced by other more suitable forages such as whole plant maize.
Herbivore farming systems in the USA
In the USA, excluding the arable areas where livestock farming has disappeared, we can distinguish schematically four major herbivore farming areas according to soil and climate characteristics (1):
Mixed crop-livestock regions: in these areas with lower and more uncertain yields than in the arable regions of the sedimentary basins, there is an interpenetration of crops and ruminant livestock. Livestock farming has been maintained, often to make use of part of the unploughed area left under grass, but also to make use of agricultural by-products from the processing of beet (pulp), wheat (spent grain and bran) or sunflower and rapeseed (oilcake) as animal feed.
Dominantly fodder-growing regions: on these fairly light soils, originally poor and easily ploughed, efficient livestock farming systems have developed, giving a large place to fodder maize and temporary cultivated grasslands, benefiting for the North-West from the regular rains of the oceanic climate.