<The basic  truth is that mammals mothers milk is intended to nurture her
infant child to
 maturity.>

it is just your assumption that it must be *limited* to this.  I am
providing a counter-example.
The cats relish it, but in appropriate amounts as they judge necessary: if a
large bowl of milk was put out for them, maybe half was drunk.  As for fish
or meat.  They clearly operate on fantastically-well tuned instinct. Such as
the routine of play and sleep.  The time for when weaning must stop and the
mother to cast the offspring out.  etc

You shoud try to think, rather than jump up and down on the spot.

Andrew