Development's opportunities for family farms often present the intensification of a specialized production and diversification of livestock and crop systems as two opposed pathways to enhance agricultural viability. In the Brazilian Cerrados, family agriculture is an exemplar case of these two dynamics. On the one hand, a structured and growing milk chain supply offers a real opportunity for smallholder farms. More and more farms, from agrarian reform settlements, specialize and intensify in dairy production. On the other hand, opportunities for diversification exist too, thanks to the support policy of family farms of the Brazilian government. We studied work organization of 15 dairy farmers, in an agrarian reform settlement in the municipality of Unaí, using a work method assessment developed in France (QuaeWork). We supposed that the dynamics of changes tending to specialization or diversification have different implications on work organization during the year. Our results show that the dynamics of development have direct implications on the work organization, as work durations, work distribution over the year and the calculated time available for the farmers (room for manoeuvre in time). For a given family, depending on workforce availability and equipment, one or another dynamic of change could be possible. Work organization induces possible evolution of family farms. These results could help research and development organizations to support family farms dynamics.