The book Comparison of rearing systems for dairy heifers: Body performance and production costs was conceived by professionals who have accumulated practical and theoretical experience in their careers on a topic relevant to science and to rural producers. With the credibility of technicians and operators who experience the real situations of the field and the management of cattle. This is a study on the physiological performance and production costs of Dutch heifers in confined and grazing production systems. From weaning to the beginning of reproductive life, the animals were evaluated under the animal welfare (Welfare Quality, 2009). More precisely, in body performance (body score, height and weight) and reproductive measurements (age, oestrus and artificial insemination). In a context of the southwestern region of Paraná, which has the largest dairy basin in the state, 27% of state production and 3% of national production.