The aim of this study was to determine the effect of gender status and concentrate supplementation level on the fattening process in beef crosses with various maturity types. The animals were fattened in two dietary treatments groups differing in the level of concentrate supplementation, analogous in terms of sire breed and gender status. Feed intake was recorded. Body weight, dry matter intake and feed efficiency were analysed using the Gompertz model in 36 bulls and 36 steers, crosses of Polish Holstein-Friesian (PHF) cows and beef bulls (Hereford – HH, Limousin – LM, Charolais – CH), aged 300 to 550 days. The performance of the Gompertz model was assessed by calculating the coefficient of determination. Results showed that animals of all genotypes fed diets with a higher concentrate level were characterised by a higher growth rate. PHF × HH crosses reached their peak growth rate between 400 and 450 days of age, regardless of feeding level. On the other hand, PHF × LM crosses reached the maximum growth rate faster at the higher level of concentrate supplementation compared to the lower level (350 vs. 450 days of age). Therefore, PHF × CH bulls should be fed more intensively than steers due to the strong effect of gender status on their relative growth rate and feed efficiency. The analysis of growth curves in beef cattle can improve feed efficiency and help meet the nutrient requirements of animals at different growth stages. Predictive models could be used to estimate the breeding value of beef cattle and support selection for economically significant traits.