Ok so my nearly 4 month old dd has been combination fed from about 4 weeks I'm using cow and gate what I used for my other 2 dc but she still will only take about 2 1/2oz every 3 hrs which I don't mind but I have to force it down her she doesn't seem to like it I was thinking of changing to aptimal I know they are made by the same company and only have one different ingredient but thought she might like the taste better as it's ment to be more like breastmilk has anybody changed formula do I need to do it gradually or can I just swap it over??