The increase in productivity in dairy farming will be essential to ensure increases in the production and supply of milk and milk products to meet the world's growing population. Appropriate technologies should be developed and adopted to enable increased productivity in a sustainable way, ensuring greater milk production with reduced number of animals and farming area. The efficient use of dietary nutrients is one of the premises of sustainable production systems, since their inefficient use not only results in excessive losses which are potentially harmful to the environment, but also affects the economic viability of dairy farming. Thus, this project aims to develop and integrate feed efficiency metrics for dairy cattle and to characterize the association between indicators of efficiency and production, nutritional, behavioral, physical, reproductive and economic parameters. Experiments are conducted to determine the feed efficiency of Holstein-Gyr females in stages of breeding, rearing, pre-birth, lactation and dry period, allowing the generation of a consistent database from the same population of animals. The feeding efficiencies of Gyr and Girolando bulls are also evaluated. During the experimental tests, behavioral parameters are evaluated through the use of precision technologies, among which electronic mangers and troughs, and rumination and activity sensors. Reproductive evaluations are conducted in heifers, cows and bulls. Metabolic parameters and the energy balance throughout lactation are also evaluated in primiparous cows. A detailed metabolic study will be carried out on the heifers that end up exhibiting divergent phenotypes for feeding efficiency in order to determine and understand the causes of such a difference. Also, an analysis of the transcriptional profile in liver and adipose tissue will be performed, allowing the identification of differentially expressed specific metabolic pathways. Once the metabolism test is concluded, a bioenergetic essay will be carried out. These assessments will allow achieving conceptual and methodological advances in the evaluation of feeding efficiency for dairy cattle. Indirect and less laborious feeding efficiency measuring tools will be evaluated, in order to facilitate the expansion of the generation of qualified phenotypes for feeding efficiency. The information and technologies developed in the project will be consolidated and disseminated to the target beneficiaries. Furthermore, it will be constructed a standard protocol for the evaluation of feeding efficiency for future use in dairy cattle breeding programs. The results being generated in this project will contribute to increased productivity and economic efficiency of milk production systems in Brazil, consolidating the country as a leader, not only in food production but also in the generation of sustainable technologies for animal production in the tropics.