it really depends on the infant. my youngest was probably only drinking 4 ounces at that age but she was tiny, she was only drinking 6 ounces by a year. but my other two were on 6 ounces by then. i think the normal recommendation is between 24-32 ounces daily.
Just feed on demand. I used to ask everyone the same question but the answers were so scattered! My son eats cereal for breakfast, crackers for lunch, and a fruit and veggie for dinner. And he will have a 6 or 8 ounce bottle around 6 times in a 24 hour period. We started doing this at about 6 months. He is 7 1/2 months now and growing like a weed!!
I literally just got back from my son's 6 month check up. I told the dr that I was feeding him 5 bottles a day with 6 oz in each bottle, which totals 30 oz a day. She said that sounds just right. Hope this helps!