my son just started dointg this the last couple of days too, he wants the bottle but he will only drink 4 oz , in the evening he still drinks 6-8 oz and sometimes another m=6-8 oz bottle, but its a struggle to get him to eat it, he gets excited when he sees it, but often takes a bit spits it out and then comes back to me for more, and will repeat the same process for an hour i have never tried putting formula in a sippy cup but i am going to to try that today if he doesnt take his bottle