Genetic parameters of beef characters and the genetic relationship between meat and milk production in British Friesian cattle

SUMMARYA beef progeny test was organized for 66 British Friesian bulls standing at AI centres in England. Eighty-one progeny groups averaging 8-5 steers each were reared on the farms of various co-operating organizations and their growth and carcass characters were recorded. Heritability of various measurements of gain varied from 0 to 0·34, of carcass conformation measures from 0·24 to 0·50, of muscle and fat percentage in the rib joint was 0·58 and 0·46 respectively, of other measures of fatness varied from 0·04 to 0·18, of weight of feet was 0·4 and of weight of hide 0·5.Phenotypic correlations among beef characters gave no indication that carcass composition could be predicted from the external carcass measurements or subjective scores used in this study. Genetic correlations suggested that selection for weight for age would produce a fatter and more compact carcass. Genetic correlations were high and negative between milk yield (contemporary comparison) and weight for age, carcass weight/length, and blockiness of leg, and high and positive between milk yield, and carcass depth/length and percentage bone in the rib joint. Their standard errors were also high.