Estimates of Genetic Parameters for Mature Weight for Beef Cows in the Wokalup Selection Experiment

Weights of Polled Hereford and ‘Wokalup’ cows in the Wokalup selection experiment were obtained monthly, with up to 11 years of records per cow available. Mature weights were analysed treating them as repeated records per animal and by fitting a Gompertz growth curve for each animal. Estimates of heritabilities for mature weight were 0.3 to 0.4 for Herefords and 0.5 to 0.6 for Wokalups, and 0.3 for rate of maturation in both breeds. Genetic correlations with cannon bone length at birth were moderate to high, with earlier maturing animals tending to have shorter cannon bones. Implications on selection for mature size are discussed.