Continental bulls of high genetic potential for lean tissue growth (½ Blonde d’Aquitaine ⅜ Charolais genotype) have exhibited high rates of liveweight and carcass gain when grass silage based diets were offered with a moderate proportion of concentrates, i.e. concentrates comprising 0.40 of total dry matter intake (Patterson et al., 1994). It was the objective of the present experiment to examine the effect of forage to concentrate ratio in the diet on growth rate and carcass composition.

The experiment was a five treatment continuous design randomised block arrangement with five concentrate ratios in the total diet (DM basis) namely: 0.25, 0.40, 0.55, 0.68 and 0.75 and grass silage (D value 730 g/kg) as the sole forage. The diets were fed ad libitum. A total of 45 continental bulls (½ Blonde d’Aquitaine ⅜ Charolais) were used with mean initial and final live weights of 467 and 651 kg respectively.