In the north-west of Vietnam, mixed farms integrating crop and livestock production are evolving in line with trends towards intensification of crop and livestock production systems (chemical fertilisers and pesticides, motorisation, animal feed, improved seeds and breeds, AI, vet). This has been accompanied by an increase in the size of farms (increase in herd, consolidation of farms with an increase in surface area) and the emergence of specialised farms (market gardens, fruit and industrial plantations, pig commercial farms). Changes in production systems are altering farming practices and exchanges between crops and livestock, and raising questions about the productive and environmental performance of farms, and their role in the sustainability of the territory. Using a model in Dien Bien district in north-west Vietnam, we studied crop-livestock integration practices and the associated biomass flows on a farm scale (between the farm compartments) and on the scale of the territory between farms. Rebuilding the multi-scale biomass flow network makes it possible to analyse the functioning of the overall farming system integrating crop and livestock production and to determine the performance associated with these practices and farms in terms of recycling, autonomy and efficiency, as well as productivity. This work shows that the diversity of farms in the area can be distinguished by different levels of autonomy for crop fertilisation and animal feed. This study confirms that the integration of agriculture and livestock farming can be associated with an intensification of production systems on certain farms. On a regional scale, lowland rice production is particularly important for feeding ruminants and monogastric animals. Fruit and vegetable growers are dependent on mixed farming systems to ensure the fertility of their crops. All components of the systems have been involved in the circular economy developed around agriculture.