Effect of a preweaning growth restriction on the subsequent growth andmeat quality of yearling steers and heifers

Abstract

The eating quality of 3 'cuts' of meat was assessed on carcasses of steers (n = 46) and heifers (n = 33) when slaughtered at 17 months of age, following preweaning growth restriction. Growth restriction (for 115 days to weaning) was imposed on half the group ('low'; n = 39 steers and heifers), followed by 2 periods of high-quality nutrition for all animals on (i) pastures (180 days) and (ii) on a grain diet in a feedlot (85 days). Preweaning growth rates (mean and standard error of difference) of steers and heifers on the 'high' treatment (905 v. 838 ± 35.0 g/day) were effectively halved (498 v. 434 ± 35.0 g/day) in the restricted 'low' group. However, no significant compensatory growth occurred when these weight-restricted weaners grazed high-quality pastures, nor during their period in the feedlot. At slaughter, the predicted liveweight of 'high'-growth steers was higher than that of 'low'-growth steers (477 v. 416 ± 11.5 kg) and they had a heavier carcass weight (251 v. 221 ± 7.2 kg). There was no difference between the meat quality (MQ4) scores of meat samples from 'low' or 'high' carcasses in which cuts of blade (2302 'bolar blade', AUS-MEAT 1998) scored higher than rump (2110 'rostbiff', AUS-MEAT 1998) and striploin (2140 striploin, AUS-MEAT 1998) samples. The study has highlighted the persistent effect of undernutrition in early life on final liveweights of Hereford cattle and the consequent reduction in their carcass weight. However, there was no carryover effect of early nutrition on meat quality.