Genetic parameters of growth, feed intake, feed conversion and carcass composition of dual-purpose bulls in...

Genetic parameters for growth, total energy intake, feed conversion ratio, average daily energy intake and carcass composition were estimated in an experiment with 650 bull calves from 31 half-sib groups of Holstein Friesian or Brown Swiss sires. All traits analyzed had an amount of additive genetic variance that allows for considerable response to selection. No interaction between genotype (sire group) and proportion of roughage in the diet was found. Daily gain was strongly correlated negatively with feed conversion ratio but positively correlated with daily energy intake. Results indicate that genetic selection for either daily gain or average daily energy intake would decrease carcass fatness at a constant slaughter weight. However, the environmental correlation between daily energy intake and carcass fatness was positive.