in my humble opinion, that is waaaay to much to be fed at once. a super great website for any information you could ever possibly need to know about breastfeeding is kellymom.com (also shows where she's gotten all of her information). breastfed babies dont need near as much out of a bottle or at a feeding as formula fed babies do (formula isnt as easily digestable therefore more needs to be fed to get the proper nutrition) and most people are used to feeding formula to babies therefore have the tendency to feed to much breastmilk out of a bottle ... most of the time 3oz is sufficient. your baby's little tummy may just be getting a little stretched and used to being overfed so when he doesnt get quite that much from you directly its a little disappointing .. also make sure you're using the slowest flow nipple on your bottles and dont change that as long as you're also breastfeeding, or baby might get accustomed to getting milk way easier from the bottle and therefore begin a bottle preference (preferring over breast that is). hope this helps, and please checkout that website...its awesome!!
jen
by the way, i have an almost 11month old that i breastfeed, have gone to many many breastfeeding support groups at the milkworks here and have friends that are active with LLL also .. i dont know if these other moms are talking about formula feeding or feeding breastmilk from a bottle as they are very much different in the amount of calories and nutrients they contain per oz of fluid. i agree that babies inherently know how much they need, so never ever deny feeding when they want more (especially directly from you) but also keep in mind that it takes their bodies/brains 20min to realize when they're full just like adults :)