Data from purebred and crossbred cattle, consisting of the Hereford (H), Simmentaler (S) Afrikaner (A) breeds, were analysed to estimate breed additive effects, individual heterotic effects, breed maternal and average maternal heterotic effects. The traits studied were birth mass, weaning mass, and cow productivity and cow efficiency ratios. Among breed groups, crossbred calves showed higher values than purebred calves for most traits. Both two-breed and three-breed rotational systems outperformed purebred Fl crosses and backcrosses. Simmentaler additive effects expressed as a deviation from Afrikaner, were positive (P ≤0.001) for all traits. Hereford additive effects were positive (P ≤0.05) for weaning mass and cow efficiency only. Simmentaler maternal effects exceeded those of Afrikaner while Hereford maternal effects were negative for weaning mass (P ≤0.001) and cow efficiency (P ≤0.05). Individual heterosis were in most cases positive but varied from -1.6% for birth mass (H X S) to 16.6% for cow productivity (H X S). Average maternal heterosis was positive (P ≤0.01) for all traits and varied from 3.3% for birth mass to 39.4% for cow efficiency when expressed a~ a deviation from the purebred mean.