It is recommended that you stop using bottles from around 12 months as it can increase the risk of dental decay. So I would start trying a sippy cup.

Also from 12 months, they shouldn't have more than 3 cups of milk a day (a cup in this sense is usually 150 - 200 mls), as it can interfere with solids eating. Also dairy can be hard on tummies, even in adults. There is no reason to give formula after 12 months or once cows' milk is fully established approaching 12 months. HTH.