Growth and carcass traits of bulls and veal calves of continental cattle breeds 1. Growth and food conversion efficiency

Abstract

ABSTRACTBetween six and 11 twin pairs each of the breeds Braunvieh (BV), Fleckvieh (FV), Grauvieh (GV), Pinzgauer (Pi) and Friesians (Fr) were either treated uniformly or separated and fattened to veal or to yearling bull stage. The aim of the experiment was the comparison of Central European breeds and to investigate genotype × rearing system interaction both within and between breeds. Veal calves were slaughtered at about 120 to 150 kg live weight (proportionately about 0·13 of estimated mature weight of bulls) and yearling bulls at 410 to 460 kg live weight, corresponding to proportionately 0·38 of estimated mature weight. In general, the dual-purpose breeds had higher growth rates both absolute (AGR) and relative (RGR) and better food conversion ratios (FCR) than the dairy breed, Friesian, and this was true irrespective of whether correlations were made to constant age, weight, maturity (equal proportion of adult weight) or carcass fatness. However, the early-weaned Friesian calves grew fastest in the early phase of the growing period and this probably reflected their superior appetite.Interactions between breeds and rearing system (bull v. veal) were significant for RGR and for maturity-corrected FCR which was mainly caused by shifting of the positions of BV and Pi.The pooled genetic correlations between performance in the different fattening categories were considerably below unity. The twin-pair correlations indicated high heritabilities which are biased by contributions from dominance and maternal environment. While in data corrected to comparable maturity, AGR and RGR were highly positively correlated, their correlation became negative in agecorrected data. The correlations with FCR displayed an equivalent change with sign reversed. The correlations between wither height and heart girth with AGR were positive for age-corrected data but negative or barely positive, respectively, for data corrected to equal maturity. Again, FCR behaved similarly but with sign reversed.