Growing up milk??????????/?

ello there i have a 13 month old and he is still on baby milk the cow and gate 1 year pluse growing up milk he has 3 bottles of milk every day ? i have tryed to give him 2 bottle of milk 1 in morning and 1 bed for bed but he does not like it he wants his 3 bottles is there any other way i could knock it down abit so he stays at 2 bottles thanks