GENETIC-PARAMETERS FOR COW WEIGHT AND CONDITION SCORE IN ANGUS, HEREFORD, AND POLL HEREFORD CATTLE

Heritabilities and genetic correlations for cow weight and body condit ion score were estimated from field data for 3 beef breeds in Australi a. In all, 8177 cows of mixed ages were weighed and scored for body co ndition at calf weaning time in seedstock herds as part of a large res earch project. The average weaning age was 212, 221, and 218 days for Angus, Hereford, and Poll Hereford, respectively. Cow weights and cond ition scores were analysed separately for each breed and estimates of genetic parameters were obtained by Restricted Maximum Likelihood (REM L). Cow weight and condition score were moderately heritable: h(2) = 0 .43 and 0.21 for Angus, 0.39 and 0.14 for Hereford, and 0.48 and 0.17 for Poll Hereford. The genetic correlation between CW and CS was 0.49, 0.65, and 0.58 for Angus, Hereford, and Poll Hereford, respectively. There is potential for providing a genetic evaluation for cow weight u sing field data in Australian beef cattle. Its modelling for inclusion in a multiple trait genetic evaluation system such as BREEDPLAN is di scussed.