Nutrition is the main cost for raising heifers, and its optimization is important to make the system efficient. To optimize nutrition management, there is the need to establish adequate nutritional requirements and to apply appropriate feeding strategies. Knowing the on-farm dairy cows mature BW and considering third-trimester pregnancy requirements are key elements to optimize dairy heifers nutritional needs. While feeding strategies such as limited feeding can adjust nutrients precisely optimizing feed efficiency, others, like the use of by-products, may have a major engagement on environmental sustainability.