The effect of anhidrous ammonia (1.5%) treatment of wheat straw (Norwegian method) on its nutritive value, was evaluated with 63 European x American Hoistein steers (266 kg), at the Quilamapu Experimental Station (INIA), Chillón, Chile. The experiment asted 104 days, in the 1987 winter. The following rations, based on treated (P-NH3) and untreated (P) straw, were evaluated: I. Untreated straw ÷ 0.45 kg fish meal + urea II. Untreated straw + 0.45 kg fish meal + 1.7 kg corn ÷ urea III. Untreated straw + 0.45kg fish meal + 3.4 kg corn + urea IV. Untreated straw + 0.75 kg fish meal + 1.7 kg corn + urea V. Straw treated with 1.5% NH3 + 0.45 fish meal VI. Straw treated with 1.5% NH3 + 0.45 fish meal + 1.7 kg corn VII. Straw treated with 1.5% NH3 + 0.45 fish meal + 3.4 kg corn VIII. Straw treated with 1.5% NH3 + 0.75 fish meal + 1.7 kg corn IX. Straw treated with 1.5% NH3 + 0.75 fish meal + 3.4kg corn The fine treatments were studied in a randomized block design, with seven replications. The rations with corn were calculated for daily gains of 0.6 to 0.7 kg/steer; P treatments inclucled urea, to offset the ammonia-nitrogen. There were no differences (P > 0.05) in uve weight gains, between P and P-NH3, nor in the effects of fish meal supplement evels. In general, protein requirements were 7 and 10% higher than NRC recommendations, according to level of ADF (25 to 46%). The NH3 treatment of straw improved (P < 0.05) total protein (N x 6.25), dry matter in vitro digestibility, and straw intake. Hemicellulose and ADF decreased (P < 0.05) and lignine and NDF were not affected. Rations with P-NH3 showed higher (P < 0.05) in vivo digestibility of D.M., total protein, and ADF. |