Denise-I have a book published in 1985 called Mammals and Their Milk, by
Lucia Anderson.  The publisher is Dodd, Mead & Co., 79 Madison Ave, N.Y.
 Also, there is a little  table in Ruth Lawrence's book with some specifics
about some animal milks.
The book I have is a children's book, by the way, so isn't terribly detailed,
but I don't know if that's what you're looking for.
     I spoke for one period to a 7th grade health class, and I started with
species'specificity.  I think that's a great way to get into the subject.