Estimates of crossbreeding parameters in a multibreed beef cattle crossbreeding project
Data from purebred and crossbred cattle, consisting of the Afrikaner (A), Simmentaler (S) and Hereford (H) breeds managed in a relatively intensive but high stocking rate environment, were analysed to estimate breed direct effects, individual heterotic effects, breed maternal and maternal heterotic effects for birth weight (BW) and weaning weight (WW). Simmentaler breed direct effects, expressed as deviation from the general mean, were positive (P ≤ 0.01) for both traits. Hereford and Afrikaner breed direct effects were negative (P ≤ 0.01) for both traits while the Afrikaner breed direct effects exceeded those of the Hereford. Afrikaner direct maternal effects were positive (P ≤ 0.01) for both traits. The Hereford direct maternal effect was negative (P ≤ 0.05) (-2.9%) for WW. Simmentaler maternal effect was negative (P ≤ 0.01) for BW but non-significant (P ≥ 0.05) for WW. Individual heterotic effects for BW were significant (P ≤ 0.01) in H x S (3.5%) and S x A (11.0%) only. Individual heterotic effects were positive (P ≤ 0.01) for WW, with that of the H x A (9.8%) and S x A (6.7%) crosses exceeding the S x H (3.1%) cross. Maternal heterotic effects were non-significant (P ≥ 0.05) for both BW and WW.