The aim of thiswork was to evaluate the weight gain of growing and finishing steers, the lifeweight gain per hectare, and the forage quality in different grass productionsystems in the winter and summer. In the winter, the black oat pasture (BOP)and star grass (SGA) production systems were evaluated. In the summer, the millet(MIL), Mombaça (MOM), and star grass (SGA) production systems were evaluatedand the effect of the production systems used in the winter on the animal performancein the summer was evaluated too. In the winter, the BOP system resulted in higherfinal body weigh (FW 381 kg) higher average daily gain (ADG 0,64 kg/day) andhigher life weight gain/ha (LWG/ha 233 kg) when compared with SGA system (FW332 kg, ADG 0,01 kg/day and LWG/ha 1,38 kg). The animals kept on BOP systemin the winter had lower performance in the summer. For the growing animals,the BOP in the winter and MIL in the summer resulted in higher final body weigh(447 kg) when compared with BOP in the winter and MOM in the summer (414 kg)and SGA in the winter and MOM in the summer (397 kg). For the finishing steers,there was no difference between the systems evaluated. In the winter, the BOPand SGA presented means levels of 15 and 5% of crude protein (CP), 51 and 81%of neutral detergent fiber (NDF), 31 and 51% of acid detergent fiber (ADF),and 81 and 45% of in vitro dry matter digestibility (IVDMD). In the summer,the SGA, MOM and MIL presented means levels of 9, 9, and 18% of CP, 65, 64,and 54% of NDF, 40, 39, and 32% of ADF, and 55, 60, and 80% of IVDMD.
