Feed intake, weaning weight and direct and maternal contributions to weaning weight were estimated for four breeding systems using data collected between 1979 and 1986 from 773 cow-calf pairs at the Elora Beef Research Centre. Breeding systems included purebred Hereford (HE), small rotational dual purpose (SR) (a four-way rotational crossing system utilizing Tarentaise, Angus, Gelbvieh and Pinzgauer breeds), large rotational beef (LR) (composed of Maine-Anjou, Simmental and Charolais) and Angus-sired large rotational beef (AL) utilizing Angus as the sire breed and LR as the maternal breed. Large rotational dams had the highest feed intakes for both dry (8.9 kg DM/d) and lactation (11.5 kg DM/d) periods. Conversely, HE calves consumed the greatest amounts of creep feed (309 kg DM), followed by AL, SR and LR. The large rotational system had the highest weaning weights (265 kg) and direct (12.3 kg greater than average of observations) and maternal (9.6 kg greater than average of observations) contributions to weaning weight, followed by AL, SR and HE for all three traits. An equation was derived for net returns that included parameters for feed intake and direct and maternal weaning weight. A linear programming model was designed to incorporate this equation as the objective function and determine the breeding system(s) that maximized net returns under various production conditions. In general, LR produced the greatest net returns, followed by SR and either AL or HE, depending on specific resource constraints (limited feed supply or herd size) included in the model.(ABSTRACT TRUNCATED AT 250 WORDS)