Breed differences and crossbreeding effects for liveweight traits in Australian meat sheep breeds

Abstract

Field data on 13 meat sheep breeds and their various crosses were analysed to examine breed differences and estimate crossbreeding effects for birth weight (Bwt), weaning weight (Wwt) and post-weaning weight (Pwt). Highly significant (P<0.001) breed additive effects were evident for Coopworth for Wwt (-3.18 Kg) and Pwt (-6.57 Kg). Significant additive effects on Bwt (0.18 Kg; P<0.01) and Wwt (0.85 Kg; P<0.001) were found for Suffolk. None of the breed combinations exhibited significant maternal heterosis. In general, direct heterosis for Bwt, Wwt and Pwt ranged from 0.2 to 1.0 Kg (4.8 to 22%), 1.0 to 1.9 Kg (3 to 5.50%), 0.2 to 2.9 Kg (0.5 to 6%), respectively.