The influence of energy supplementation (2,8 kg maize meal) of beef cows during early lactation and of creep feeding their suckling calves was investigated in two areas (Thornveld and Transitional Highland Sourveld). The cows were bred in spring to calve during the first (early calvers) or last six weeks (late calvers) of a 9O-day calving season. The gains in bodymass of the cows which calved early were significantly greater than for the late calvers. Energy supplementation had no major effect on the bodymass gains or reconception rates (CR) and intercalving intervals (ICI). In the Thornveld only 14,8% of the variation in mass gain during early lactation was attributed to supplementation. Variation in the ICI depended largely (70,5 %) on the time of calving. In the Sourveld only 23,9% of the variation in ICI was due to this factor. Cows which reconceived were heavier at calving and when mating ceased, gained more during the breeding period and had calved earlier than cows which did not reconceive (P ≤0,01). The CR was closely associated with change in bodymass (Thornveld: r = 0,72; Sourveld: r = 0,93) and bodymass at the end of mating (Thornveld : r = 0,87; Sourveld: r = 0,98). Early-born calves gained at a faster rate than those born late in the Thornveld, but not in the Sourveld. Creep feeding was beneficial for late-born calves suckled by cows which received energy supplements In the Thornveld. All creep fed calves benefitted in the Sourveld. In the Thornveld the bodymass at weaning was determined by the season of birth and creepfeedlng (31,4%) While in the Sourveld creepfeeding and bodymass of the dam at calving were significant contributors (23,1%) to variation in weaning mass.