Nan Pro can be given upto 2 years. Cow milk is better option and you can try it, and it wont cause any harm. Try introdusing small feeds to baby like 60 ml per feed for next three days, in morning. Watch out for his stool pattern. If stoll is normal, and baby is not cranky then it means baby is digesting it. Slowly you can increase feed amount and introduce it in evening as well. Hope this helps. Happy Parenting