Data on calves sired by Charolais bulls and their contemporaries in 22 commercial herds in Northern Ireland indicate that the Charolais calves were significantly heavier than their contemporaries at weaning as well as at birth. Although the weight of dam was also significantly greater for the Charolais calves, all the evidence indicated that this was not associated with calf weight and did not, therefore, invalidate the conclusion on calf weights.

The present results suggest that although interaction between breed of sire and sex is not statistically significant for calf weights neverthe-less the superiority of Charolais sires was much greater for males than for females. The interaction was significant for daily gain to weaning. Separate analyses for the two sexes indicated that the Charolais-cross males gained significantly better than their contemporaries whereas no significant difference in gain could be detected in the females.