Interchangeably either breast feeding or bottle of milk should be the main source of nutrition for the baby, as we said before, the first 12 months of life because it is essential for growth and development of their body.
Do not worry more that when the time of care or tolerance to be adding some foods, but the first few months this is usually not necessary if the baby is fed with formula milk still hungry and probably cry, but instead, if you are satisfied suck the first 10 minutes and fall asleep, letting the bottle.
Babies who are breastfed by the mother acted differently in this sense, eating enough, is the way to realize if they are gaining weight, must also be given the chest every 3 or 4 hours, and not allow that they missed shots, by the fact of being asleep, at least until they meet the 4 weeks of life, that food is essential.
At the beginning of the second week of life and between the third and sixth, the baby will experience “fits”, during which it is possible to be more hungry than usual, although you not perceived the daily growth during these “fits”, the body of your child will experience significant changes and will need fresh extra calories. If you take the bottle, you must add food in it.
If, however, your baby has nutritional problems will not gain weight properly so it is advisable to consult your pediatrician as during early lactation is critical for growth and development of children.