This work, evaluated by means of an economically simulation, the beef production systems with heifers calving by first time at two (“one year” system), three (“two years” system) and four (“traditional” system) years old. In “one year” system, the female calves had three different nutritional systems during 100 days, after weaning in the first autumn/winter, constituted by one of the alternatives: a) continuous grazing on cultivated annual ryegrass – PAST; b) continuous grazing on natural pasture plus diet – CNR; […]