Vietnam has adopted strategies to support the introduction of productive, sustainable agricultural models, while preserving non-agricultural resources: a strategy to develop livestock farming, large-scale conversion of slope crops to fruit trees and industrial crops with high value-added, protection of forests and reforestation. These strategies are changing the spatial distribution of resources and activities. In the north-west of the country, mixed farms raising large ruminant are largely dependent on pastoral resources outside the farms for animal feed (fallow land, roadsides). In Dien Bien Province, only 8% of feed requirements are covered by forage crops. Technical options for improving the fodder available on farms have been promoted, but their adoption is partly hampered by the lack of accessible farmland for fodder production. We aim to assess the effect of an ambitious scenario for developing livestock farming with agroforestry systems that include green forage production, compared with a scenario that follows current trends in livestock farming development. For a variety of farms (specialised in livestock, mixed and specialised in crops), and using a farm modelling tool adapted to the context of North Vietnam, we simulate the effect of these two scenarios on changes in herd size, available forage quantities and farm nitrogen autonomy over 15 years. The continuity scenario reproduces the current availability of fodder outside the farms, an extension of forage onto marginal land and the gradual replacement of slope crops by fruit trees. The scenario with agroforestry considers greater pressure on external resources, with a greater reduction in fallow land and slope crops as a result of reforestation and the more rapid development of forage production, based on a forage-fruit intercropping model on land currently occupied by slope crops. Farms are likely to see their herd size increase, provided the constraints imposed on outdoor pasture remain low. The growt