Vers une amélioration de l'autonomie en protéines des élevages bovins laitiers et aspects environnementaux

Towards an improved protein self-sufficiency of dairy cattle farms ; environmental aspects

How can an improvement in the protein self-sufficiency of dairy cattle farms be expected ? What would be the consequences on the farmer's income, his work, the risk of pollution, and the valorization of the farmland ? Plenty of lessons could be drawn from simulations carried out on four systems differing by the proportions of maize in the crop land. The various possibilities (scenarii) tested consisted in introducing home-grown high-protein crops, or in reducing the silage maize acreage for the benefit of conserved herbage, or in an improved utilization of grazing. These were applied to 4 typical systems in the Rhône-Alpes region, which are fairly similar to corresponding situations in other French regions. In a grassland farming system with silage cuts, compact calving dates in spring together with an increased share of hay in the winter diets, enhance the valorization of grazing, and improve the economic result, the maintenance of the territory, and the nitrogen self-sufficiency. The other scenarii are without effect on the economic results ; those that introduce high-protein crops or lucerne improve the nitrogen self-sufficiency.