In Northwest mountains of Vietnam, the smallholder livestock farms depend largely on natural pastures for animal feed. However, the management or improvement of grazing areas has not yet been recognized or regulated by local authorities. There is a need to provide reasonable evidence of the grassland-based livestock systems contribution for sustainable development. An ontology proposed by the AN2-GASL group was used to evaluate the contribution of grazing livestock systems in four dimensions: production, ecosystems, social and local development in the case of the Quài Nua commune, a northwest mountain commune of Vietnam. Livestock contributed multifunction to all types of family farms. Cattle and buffaloes make an high contribution through meat for domestic consumption, sacrifices and donations, traction force, manure production and stock value as bank saving. This study provides quantified evidence of the multi-functionality of extensive cattle production at farm and communal levels. The contribution of grazing areas for meat production, but also for the creation of employment and the revenue and profit along the beef value chain was calculated at commune level. It appears that a balance between different types of farms with different roles could be a basis for local sustainable development.