A total of 828 crossbred beef and dual-purpose type cows were allocated to three herds which were bred either artificially, artificially followed by natural service or by natural service only. Conception rates were 72,9; 88,2 and 94,3 % respectively. The increased conception rate where natural service only was used, was much more pronounced in the Bos indicus crosses (> 34 %), than in the British cross dual-purpose types (> 8 %), or the British cross Charolais types (> 6 %), indicating that the Bos indicus types were less suited to the A.I. method practised than were the Bos taurus types. Cows bred naturally conceived earlier and thus calved earlier in the season leading to an increased calving-to-breeding period the following breeding season and a reduced intercalving interval. The higher conception rate of the naturally bred group resulted in a 35,6 % greater total weaning mass than that of the group bred by A.I. only.