In France, several work models, which underlie research and tools for "work advice", coexist in approaches to analyse how livestock farming systems (LFS) function. We describe three models: "resource work", "organised work", "work and subjectivity" and specify the way in which LFS research has mobilized social science disciplines to construct them. We illustrate how they complement each other to examine the transformations in livestock farming systems, the ways in which the farming activity is carried out, the conceptions of work, as well as the workforce and technical systems.