Prolonged & repeated heating of milk affects nutrition   -
In Indian Household ,Milk is boiled more than three times a day,and hence losses most of its essential vitamins,proteins,amino acids & minerals.

Vitamins and proteins are destroyed when milk is boiled at  temp above 100 degree for 15 mins or above.
Milk is a critical source of nutrition for infants , so any loss of protien or vitamins could cause growth dificiency ,weak bones, poor muscles developement and neurological impact among long terms effects.