Ruminal degradability of the dry matter and crude protein of the corn silage, soybean meal and sorghum grain in nellore cattle: Comparison with data of the CNCPS - Rossi, P R; Silva, A G; Wanderley, R D; Bose, Max Lázaro Vieira; Boin, Celso (Revista da Sociedade Brasileira de Zootecnia, 1997)