Mixed crop–livestock systems, the world’s most widespread farming systems, promote farm resilience through diversification and allow for crop–livestock integration (CLI). Intensification and specialization challenge these systems. In Northwest Vietnam, the standard farm model is based on mixed crop–livestock family farms but is shifting towards more specialized farming systems. The aim of the current study was to identify the new balance between livestock and crops on farms in Northwest Vietnam and to examine the effects of specialization on CLI practices and production system intensification by identifying current CLI practices and performing a retrospective analysis of changes in these practices. One hundred farms were surveyed and 24 interviews on farm trajectories were conducted in Dien Bien district (Dien Bien province) between January and April 2022. Based on the level of CLI and farm diversification, seven types of farms were identified and classified into three categories: (B) mixed farms, (A) farms specializing in livestock and (C) farms specializing in crops. The study of farm trajectories revealed three main changes: the conversion of mixed crop–livestock farms into more specialized crop systems, a change from mixed crop–livestock to more specialized family livestock farms and a change in the management of large ruminant herds and their feed system from free grazing to foragefed systems. Understanding these changes will help identify drivers and potential constraints to the development of new practices for the integration of crop and livestock farming.