To face the challenges arising from decreasing water and fossil fuel resources, dairy systems will have to limit their use of irrigation, mineral nitrogen fertilisers and exogenous concentrates. Grazing is a critical aspect of energy and water-saving management. However, the quantity and quality of grazed forage are highly dependent on climatic conditions. In Atlantic French regions, grazed grasslands currently provide forage in spring and, to a lesser extent, in autumn. However, grassland production is much reduced in summer. Climate change will probably increase drought conditions in late spring and summer, and also the overall variability of grassland production annually. Trees and shrubs could provide a complementary forage resource on dairy cattle farms.