Milk is very important for babies specially in the initial days of life breast milk is very important and should be given exclusively till 5-6  months of age . formula milk should be given only as a substitute to breast milk if due to any reason it is not sufficient to fulfill the demand of the baby. according to the age different stage of formula milk are there like stage 1 till 6 months of age stage 2  from 6 months to 12 months and thereafter stage 3 . after one year cows milk should be started and any kind of health drink powder in milk should be  used only after the completion of two years of age .

Yes .You can give lactogen for babies of age group 0 to 6 month category