Forest ecosystems of Brazilian Amazonia are cleared to allow livestock production. Deforestation contributes significantly to climate change and losses of biodiversity. Degradation by scrubs reduces pasture productivity after a few years, thus leading farmers to deforest new areas. For this reason, sustaining cultivated pastures is of major importance for cattle farms. Intensive pasture management techniques have been proposed to the farmers, with little success so far. Our hypothesis is that these techniques are not implemented by farmers due to weak work organisation. Here, we assessed the diversity of forage system work of dairy farms in a municipality on the Transamazon Highway. We analysed factors explaining the adoption of intensive pasture management techniques. We monitored seven dairy farms, with a specific work assessment approach to build synthetic qualification variables and an interview of 29 dairy farmers to characterise the diversity of forage system work. Our results show four tasks related to their technical content: pasture maintenance, renovation, land maintenance and exceptional work. The total duration of work is variable, from 17 to 278 days per year, depending on the technical management choices. Some farmers are autonomous in carrying out the work, but in several cases, wage workers may contribute significantly, from 33 to 100%. We identified five types of forage system work. They oppose very simplified technical management carried out in autonomy by the family workforce to intensive techniques based on a high level of delegation to permanent wage workers. The results show that forage system work is related to the technical management choices and distribution of work between farmers and permanent wage workers. Forage system work also depends on the amount of work dedicated to the dairy herd, the role of milk in the farm, and the weight of other farming and non-farming activities. Finally, intensive pasture management techniques are linked to a high quantity of work with pasture maintenance, hired permanent workers and specialised dairy farms.