Almeida et al., 2002. Rev. Bras. Zootec., 31 (2) Supplement: 852-857

Mixed pastures of Brachiaria decumbens with Stylosanthes guianensis cv. Mineirao and B. brizantha cv. Marandu with S. guianensis cv. Mineirao, under three stocking rates (0.8, 1.2 and 1.6 AU/ha) were evaluated in terms of daily liveweight gain (DWG) and liveweight gain per hectare, in the Brazilian Savanna, in order to determine the most adequate management. A randomized block in a split-plot design with two replicates was used. The plot treatments constituted a 2*3 factorial, two grasses (Brachiaria decumbens and B. brizantha cv. Marandu) associated with Stylosanthes guianensis cv. Mineirao and three stocking rates (0.8, 1.2 and 1.6 AU/ha), and the split-plot as year seasons. Weaned Nellore steers (138 kg average initial liveweight), in the beginning of the experiment, were used. The grass, season and stocking rate affected daily average liveweight gain. Animals grazing B. decumbens showed higher DWG than those grazing B. brizantha (409*333 g/head/d). Higher DWG was observed in the rainy season in relation to the dry season (490 and 194 g/head/d). DWG decreased linearly as stocking rate increased, and values of 435, 371 and 308 g/head/d were estimated for stocking rates of 0.8, 1.2 and 1.6 AU/ha, respectively. Animals grazing B. decumbens showed higher production per hectare than those grazing B. brizantha, with liveweight gains of 464 and 352 kg/ha/year, respectively. Liveweight gain per hectare was affected by grass and year season. Production per hectare was higher in the rainy than in the dry season, with average values of 331 and 77 kg/ha/year, respectively. Stocking rate did not affect production per hectare, but there was a curvilinear tendency, indicating that the most adequate stocking rate ranged from 1.25-1.30 UA/ha.