Armand Goldblum has done research on the composition of breast milk to two
years of age.  It is essentially the same as during the first year, but with
higher levels of immune factors.  Send this doctor a copy of my chapter on
weaning (Ch. 2 from Breastfeeding: Biocultural Perspectives).  Ask him if he
recommends cows' milk, and if the milk of a different species is considered
good, then logically the milk of one's own species would be even better.
And no one ever asks how long past delivering it's calf the cow is that
produced the milk on the grocery store shelf.

Kathy Dettwyler