Effect of protein supplementation for steers fed high levels of molasses

Ignacio Ruiz N.1, Ernesto Jahn R.2, Germán Klee G.3 y Pablo Millas A.4

Forty eight steers, with 400 kg of initial uve weight, were distributed in a complete factorial arrangement to six treatments, in a randomized block design. The factors evaluated were: three molasses levels, 1.0, 1.7, and 2.4 kg per 100 kg of body weight, and two protein levels, 0.31 and 0.46 kg of total protein per 100 kg of body weight. Protein was equalizedwith rapeseed meal;wheatstrawwas used as roughage, in variable amounts according to treatment. The protein level of 0.31 kg/100 kg L.W. is the requirement to gain 1.4 kg/day. The rations were adjusted every four weeks, according to the changes in liveweight. The interaction molasses by protein levels was non significant (P > 0.05). However, there was a trend for higher gains with increased rnolasses levels, at the higher protein level; such perfomance was not observed in the lower protein level. Steers on the higher protein leve) had a significantly higher weight 9am than on the lower protein level. The daily weight gains were 0.70 and 0.40 kg, for the high and the low protein levels, respectively. A digestibility trial of ‘sorne rations showed that molasses inclusion increased dry matter, protein, and nitrogen free extract digestibility, but decreased crude fiber digestibility.

1 Instituto de Investigaciones Agropecuarias (INIA), Casilla 5427, Santiago, Chile.
2 Estación Experimental Quilamapu (INIA), Casilla 426, Chillán, Chile.
3 Subestación Experimental Humán (INIA), CasilIa 767, Los Angeles, Chile.
4 Avenida Argentina s/n, Casa 53, Población ANSA, Chillán, Chile.