After my childs second birthday, should i switch her from whole milk to reduced fat milk?

Depends: Before 2 we encourage regular milk to assure a fat source while the brain ( which uses it for insulating nerves)is growing rapidly. As the growth starts to slow, the extra is not as important. Milk then becomes more important for the calcium it supplies, which the reduced fat milks do well. If the kid is very lean, it may be reasonable to continue regular milk.