They don't need to drink cows milk as their formula has everything they need. Cows milk doesn't have all the nutrients. However I started offering a little cows milk in a beaker from about 10months which Morgan just used to take sips of. Alongside him still having his formula. Got him used to it, before transitioning him over once he was 1.

Do you think it will be okay in her formula? Shes been having it in her food from 6 months but started it in her bottles x

Babies can have cows milk in their cereal & cooking from 6months. So yeh 10months would be fine.