The experiment evaluated the weight gain during the finishing period of 24 months old beef steers, with an average initial weight of 365kg, supplemented on oats plus ryegrass pasture, with a residue of 2356kg DM/ha, 14.84% CP and a IVOMD of 56.31%. Two levels of supplementation, corresponding to 0.5 or 1% of the live weight, associated or not with lasalocid, were used. The concentrate used for supplementation was ground corn. The treatments that included lasalocid, it was mixed to the corn in a proportion that allowed a consumption of 225mg per animal per day. The experimental design used was the completely randomized, in a 2x2 factorial scheme. No significant interaction, for average daily weight gain, was observed between the supplementation level and the use of lasalocid. Average daily weight gain was 1.501 and 1.532kg/day for the .5 and 1% supplementation level, respectively, and 1.456 and 1.577kg/day for the inclusion or not of lasalocid. The results showed that in terms of daily weight gain, there is no advantage of increasing the supplementation level from .5 to 1%, indicating also that in this range of supplementation only a substitutive effect occurs.
oats; ryegrass; ionophor; corn; grazing; weight gain
