The difficulty in designing an optimal breeding programme arises from a conflict between improvement in genetic gain and increase in inbreeding since selection procedures which increase genetic progress are usually associated with increased rates of inbreeding. Best linear unbiased prediction (BLUP) has optimal properties regarding the expected genetic gain after one generation of selection. However, since full genetic relationships are accounted for, selected animals are likely to be more related, leading to a higher rate of inbreeding and a larger decrease in genetic variance than less accurate methods.