is a matter of time baby get used to the teat and know how to suck properly. is the same as latching. at first, baby doesnt know how to latch but after a while, after many prac, she knows how to. but of cos during the time when she is trying to get used to a teat, she will swallow a lot of gas but after a while, after she has learnt, should be quite ok.
usu if a baby is solely bott fed from the start with no latch and using only one teat, she will know to to suck effectively fr the teat. but if baby was latching and is intro bott, there will be probs of her not knowing how to suck and therefore swallow air. so is trickier to intro bott to a baby who is latching fully than a baby who has never been latched.