Breastfeeding and the Use of Human Milk (RE9729) -- This is the one I've been searching for. Under "Recommended Breastfeeding Practices": Exclusive breastfeeding is ideal nutrition and sufficient to support optimal growth and development for approximately the first 6 months after birth. Infants weaned before 12 months of age should not receive cow's milk feedings but should receive iron-fortified infant formula. Gradual introduction of iron-enriched solid foods in the second half of the first year should complement the breast milk diet. It is recommended that breastfeeding continue for at least 12 months, and thereafter for as long as mutually desired.