A boar has sired 20 litters averaging 7.8 weaned pigs each. Postweaning average daily gains of his progeny average .06 lb per day above contemporary group means. Heritability of postweaning gain is .28 and c²FS, a measure of covariation among postweaning gains of littermates that is caused by common environment (in this case, the covariation due to a common dam), is estimated to be about .07 Use a single-source selection index to estimate the boar’s breeding value for post weaning average daily gain.