i am currently at the point where i am trying to introduce a formula milk to my nearly five and half month daughter (Hipp Organic 0+)she refused it today on the first attempt but took breastmilk instead. not sure if this was due to teat or taste of milk. i have tried using my manual pump but after 15 mins, got 1oz so gave up. admittedly, i have not been expressing regularly as i am at home at present so feed when she is hungry. i am considering an electric pump but wondered do any mums have any idea of what volume is expressed via an electric pump, lets say in half an hour? i am trying to prepare her to take a bottle for when i return to work in august and in preference, i would prefer her to have breastmilk. thanks in advance.