Effectt of supplements on forage degradability of Brachiaria brizantha cv. Marandu graz ed by steers

The supplementation effect was evaluated using crossbred rumen-fistulated steers maintained in a Brachiaria brizantha cv. marandu pasture. The animals received energy supplementation (corn-COR); low degradability protein supplementation (corn gluten-GLU); and high degradability protein supplementation (soybean-SBM) at two levels N1 (+/-0.5 kg/an/day) and N2 (+/-1.5 kg/an/day); or no supplementation (Control). The factorial (3x2), plus the control, was studied according to complete randomized block design with three replications. The supplementation did not affect (P>0.05) the potential degradability (POD), the effective degradability (EFD), and the degradation rates (DR) of the forage (extrusa). The GLU supplementation provided higher (P<0.05) EFD of the NIDN fraction than the SBM, and both did not differ (P>0.05) of the COR treatment. The data allowed to conclude that the supplementation used did not provide alterations in the forage degradability, probably due to the low N-NH3 level and the non-variation of the ruminal pH.