You could try offering the bottle in a different form too! When my LO was about 7 months, he decided to go from BF to FF. He lost interest in nursing (and with 8 teeth, I was happy for him to be done!). Anyway, what made it attractive was that I had started doing the final feed of the day a formula bottle via cup and straw! Once he figure out how to sip from a straw, no boobie and no bottle would do.
It was less effort for him and it went down fast! In less than two minutes he'd slurp everything down, belch loudly, and be happy as can be. Another positiv is that I don't have any bottles to wean him off of in the future!