The influence of level of concentrate feeding on the voluntary intake of grass and on live-weight gain by cattle

Abstract

SUMMARYGrazing and stall-feeding experiments were conducted to examine the effect of giving different amounts of cereal-protein concentrate with grass on the live-weight gain of cattle initially 6 months of age. The effect of level of concentrate on grass intake was also studied in the indoor trial. Experiment 1 took place at pasture, with two stocking rates (high and low) and three levels of supplementation at each stocking rate. The response to supplementation, and rate of live-weight gain by the unsupplemented groups was similar at both stocking rates for a 101-day period from late April to mid-August. The results are discussed in relation to other pasture supplementation experiments, and to those obtained in the indoor experiment. Experiment 2 (stall-feeding) consisted of five levels of concentrate feeding from zero to 100% of the diet. There was little increase in total intake as the proportion of concentrate in the diet increased, and the relationship between grass intake and concentrate intake was rectilinear.Gut fill estimates are presented for each level of concentrate feeding, and results for empty body-weight gain are discussed in relation to live-weight gains. There was a linear increase in weight gain with increasing proportion of concentrate in the diet. Empty body-weight gain is recommended as a less biased assessment of the response of cattle to concentrates given with pasture or forages.