With my oldest I stopped breastfeeding at about 9.5 months as my milk supply started to dry up as I was pregnant again. I found that bottles with a normal teat were no good for her, she just could not suck out of them for some reason.
What I did was give her formula in a bottle but used the avent sipper teats with the valve in them. They were fantastic as she was used to them as I had previously given her water in sippy cups with this teat from the age of 6 months.
I originally planned to stop bf at 6 months but it was going so well I continued till then. I have a four month old now and I will probably keep bf till about 9 months or so and will try using the same avent sipper teat with her.
Also, my oldest has from 6 months also used the tommee tippee straw cups which are also very good particularly for bf babies.
4 lovely munchkins DD 10/03, DD 03/05, DS 10/06 &