Resumo

MARTINS, Jorge Dubal; RESTLE, João  e  BARRETO, Ismar Leal. Animal production on alexandergrass (Brachiaria plantaginea (Link) Hitchc), submitted to nitrogen levels. Cienc. Rural [online]. 2000, vol.30, n.5, pp. 887-892. ISSN 0103-8478.  http://dx.doi.org/10.1590/S0103-84782000000500025.

The effect of nitrogen levels (0, 100 and 200kg/ha of N), in the form of urea, was studied on Alexandergrass (Brachiaria plantaginea) pasture, under grazing conditions. The grazing system used was the continuous grazing with a daily average supply of 14.41kg DM/100kg of live weight. Average daily live weight gain, "in vitro" organic matter digestibility and botanical composition were not affected by the nitrogen level. The use of nitrogen affected significantly live weight gain per ha (Y=213.9+.729X; R²=.64), pasture daily acumulation rate (Y=14.75+.194X; R²=.80), total dry matter production/ha (Y=4,295+20.48X; R²=.90), crude protein contend (Y=4.61+.0175X; R²=.97), stocking rate (Y=1,092.9+3.732X; R²=.91) and number of animals.day/ha (Y=261.18+.728X; R²=.87). The live weigth gain/ha, during the 73 days grazing period, was 208,62; 297,36 and 354,46kg, respectively, for 0, 100 and 200kg/ha of N. The results showed that when adequately fertilized Alexandergrass can be used for animal production resulting in satisfactory weight gain/ha.

Palavras-chave : Alexandergrass; animal performance; continuous grazing; digestibility; nitrogen; pasture; urea.