I hope that you are talking about 'breast milk' and not cow's milk. If you are breast feeding, you should be breast feeding your newborn 'on demand'. Newborns will nurse quite often and you will know when they are hungry. A newborn should NEVER be fed cow's milk. On an average, a week old baby drinks about 2 1/2-4 ozs of breast milk/formula at one feeding and usually feed about 4-6 times a day.