Valorising a diversity of biomasses to meet the technical, environmental and societal challenges of ruminant farming

Through the importance of the surface area used (more than half of the French agricultural area) and the importation of part of protein-rich feedstuffs, ruminant feed is at the heart of the technical, economic, environmental and societal challenges facing livestock farming. Climate change is already affecting forage calendars and available feed resources. Faced with these challenges, many levers exist either to adapt existing resources or to develop new ones. They are based on the adaptation of grasslands (introduction of species resilient to climate change) and their management, the use of cereal-legume intercrops, summer catch crops, C4 photosynthetic plants and the development of agroforestry. The diver-sification of cropping systems made necessary by the reduction of synthetic fertilizers and pesticides should provide new resources for livestock farming (forage and seed legumes, intercropping). New technological processes, such as the bio-refining of fodder, offer prospects, as does better use of the co-products of the agri-food industry. The use of insects as a source of protein is not yet authorized for ruminant farming in the EU. The use of algae raises the question of the volumes needed to feed ruminants, but they offer prospects as feed additives to reduce enteric methane emissions. Characterizing these new feed resources raises many research and development questions. This requires a sufficient amount of new data obtained from in vivo reference feed evaluation methods to be able to strengthen the databases used for feed value tables and prediction tools.