Most health professionals do not recommend feeding a baby from a bottle until after about 4 to 6 weeks after birth so that breast-feeding can be well-established. A baby who is fed with a bottle too soon may develop a preference for the nipple of the bottle over the breast. This may occur because it requires less effort to obtain milk from an artificial nipple.
Talk to your health professional if you wish to start feeding your baby breast-milk from a bottle before he or she is 4 to 6 weeks old.
WebMD Medical Reference from Healthwise