The successful dairy breeding programs of the Zebu Gyr and Guzera breeds, conducted in close and consolidated partnership with the Gyr and Guzera Breeders' Associations, counted over the years on the indispensable collaboration of crossbred herds for carrying out the progeny and milk control tests. These herds are characterized by pasture-based milk production, with low inputs and technologies, and the practice of crossbreeding. The crosses practiced, however, are the result of unplanned mating, despite the extensive knowledge obtained in several studies conducted in Brazil. These studies pointed out the potential of each genetic composition generated in outlined crosses for each production system, focusing on the performance of several traits of economic importance. Despite this, Brazil has become the world’s third largest milk producer. However, the difficult scenario of dairy farming has currently presented several challenges to farmers, especially those depending on crossbred animals for production, hampering their profitability and casting dim prospects for staying in such activity. In addition, the Zebu breeds, which once contributed to crossbreeding only with their rusticity, were the target of intense selection for productive traits and probably started to contribute with their improved genetics to the performance of crossbred animals. But little is known about the zootechnical performance of these herds that have been incorporating the proven bull technology, the effective contribution that their participation in breeding programs has given, and about the technological and economic advances that may have occurred in that period, as well as about their determinants. Furthermore, we believe that conducting an in-depth study based on data collected in these herds, involving the various aspects of a production system, we may bring understanding about the activity practiced in them; their productivity and profitability; as well as on the bottlenecks for their performance, so as to raise their demands on research and development, and to guide strategies for their sustainability. Therefore, the objective of this study was to characterize and evaluate milk production systems based on the use of crossbred animals under grazing conditions in relation to various zootechnical and technical-economic aspects of the activity. We have the conviction that the results to be obtained with this study, although carried out within the scope of the collaborating herds in the breeding programs, will contribute to the development of the other crossbreed herds in the country. For that purpose, a broad questionnaire will raise data related to the productive and technological profile of these properties, which will be analyzed for their characterization. Their revenues and expenses will also be monitored for a period of one year to calculate production costs and assess economic performance. Animal welfare indicators will also be observed, as adapted from the Welfare Quality Protocol, limited to the definition of those focused on well-being with knowledge on animal performance. The study has the collaboration of researchers from the Animal Science Institute of São Paulo (IZ).