Rice straw treated with urea. Chemical evaluation and digestibility of rations using holstein steer

Jorge González U.1 y Germán Klee G.1

In arder to evaluate two forms of urea addition to rice straw, a trial was eondueted during the fallwinter period of 1991 at Quilamapu Exp. Station. Treatments were: I. untreated rice straw; II. rice straw with 6% urea water diluted (15 L/100 kg). and III. rice straw with 6% grounded urea. Straw was stored in cylinders like structures made out of wire netting. Straw chemical analysis and in vivo ratians digestibility were made under Iignine procedure. The experimental desing was a completly randomized block. Significant differences (P < 0.05) among treatment far straw total nitrogan, acid detergent tiber (A.D.F.) and metabolizable energy were found. Straw with grounded urea (III) showed the higest value of total nitrogen (3.39%) and metabolizable energy (1.74 Mcal/kg) and the lowest level of A.D.F 47.5%. There were significant differences in dry malter apparent digestibility (P < 0.01) and in total protein digestibility ( P < 0.05) but not in A.D.F P > 0.5). Measuremant of digestibility in vivo of ratians lika those usad in this research would seem better if using the total colleetion of feces and urine and increasing the sampling collection procedure.

Keywords: rice, steers, straw, urea, improvement, evaluation.
1 Estación Experimental Quilamapu (INIA). Casilla 426. Chillán, Chile.