Background and Methodology
Friesian steers slaughtered at the same fasted live weight were of different carcass composition if they had been fed on a barley-based diet as contrasted with a pasture diet. The differences in carcass composition could have been due to either a direct effect of the different diets or indirectly by the effect on growth rate. This aim of this experiment was to determine whether the differences in carcass composition reported in other studies were due either to a direct dietary effect or to growth rate. Twenty one Friesian steers were grown to a final fasted weight of 469 kg. Seven of the steers grazed irrigated ryegrass-white clover pasture, seven steers were fed on a high energy ration ad libitum and seven were given a ration of the same composition as the second group but at a restricted amount.
Findings
There were no significant differences in carcass weigh between the three groups. The grain ad libitum group had 51.5% more (P<0.05) omental fat than the pasture group and the restricted group 28.9% more (P<0.05) than the pasture group. In dissections of the 9th, 10th and 11th ribs the grain ad libitum group had 35.4% fat, the restricted grain group 32.8% and the pasture group 26.5%, the proportion of fat being significantly (P<0.05) lower in the pasture group than in the grain ad libitum group. No significant differences were found in tenderness, juiciness or flavor between the three groups.
Reference:
Davies, H. L. (1977). Continued studies on the effect of grain or pasture on the carcass composition and meat quality of Friesian Steers. Aust. J. Agric. Res. 28: 755-61.