Performance of lambs and steers given monensin with different levels of barley

Abstract

The effect of barley level and monensin on feedlot performance by lambs and steers was investigated in two experiments. Monensin was given at 0 and 33mg/kg of food in lamb and steer diets, which contained bailey at levels from 300 to 900g/kg. Food consumption by lambs was not affected by monensin but intakes decreased with increasing levels of barley (P<005). Food intake by steers decreased in a linear manner with increasing levels of barley (P<001) and averaged 80g/kg lower when monensin was fed (P<005). Monensin improved lamb gains by 350g/kg (P<0-001), but had no effect on steer performance. Feeding monensin improved average food efficiency in lambs and steers by 27 and 4%, respectively. Carcass characteristics were not influenced by monensin, but heavier carcasses (P<0-01) in steers given the high barley rations were also fatter (P< 0-001).