Transitions for anyone are not easy - we all like our "comfort blankets" and we don't like to change. Doing the same thing is soothing and can really pacify an individual, especially a baby. And transitioning a baby from the breast to the bottle or bottle to the sippy cup can be a daunting task. Afterall, it seems like everything for both mommy/parents and baby has to be perfect in order to make the smoothest of transitions (i.e. no sicknesses, having the right bottle/sippy cup, no major events that are occurring during the transition period, etc.). But the one thing that I have learned with my 3 kids are that in order to have successful feeding transition - you need to make them gradual.
For example, I recently transitioned my youngest from the bottle to the sippy cup. We started the transition when he was about 11 months old (with the goal to have him fully transitioned by his 1st birthday but that didn't happen and it was OK, we knew that he would eventually make the transition). Anyway, we started out by taking away one or two of his milk bottles and replacing it with sippy cup. He took to this transition well, although we had to try a lot, and I mean a lot of sippy cups (both straw and cup styles) before we found the one that he preferred. Once we found the cups that he liked, we started removing the remaining daytime bottles and replaced them with the sippy's. We did this for quite a while. We tried to replace his morning or night bottle with the sippy cup but he adamantly refused for many, many weeks. But we kept with the transition and I paid special attention to which bottle time mattered the most to him - his night time bottle. We then worked on the transition of only the morning bottle to the sippy cup. We did this for a few weeks and eventually we succeeded. Finally, we had to work on the night time bottle. What I did to help smooth out this transition was to alternate bottle and sippy cup every other day. On the nights that he had the sippy cup, he didn't drink a lot and I knew that he would be up in the middle of the night hungry but I also knew that this would be a temporary schedule change and that he would eventually take to the sippy cup and sleep through the night. Well, the transition didn't take as long as I had anticipated - he had fully accepted the sippy cup by day 3 of the night time transition!! And now we are bottle free - not a single bottle or bottle accessory is present in our house - what a great feeling!!
I pretty much did the same transitioning method with the transition from breast to bottle. I replaced daily feedings with the bottle and eventually the morning time feedings and finally the night time feedings. This gradual method allows time for baby to adjust to the new and different feeding method and to accept it. As I mentioned before, transitions are not easy for anyone but be patient and be consistent and you'll have a smooth transition and a satisfied and happy baby in the end. Good Luck!
P.S. Now I can't wait to potty train him and be free of diapers!! Stay tuned....