I think fresh is much better for several reasons. 1) It carries a lot more nutrition. 2) It's much easier to digest because it comes with it's own enzymes 3) If you start your children out on cooked foods, you are programing them to accept and want a lot of cooked and processed foods when they get older.
Cows milk is never a nutritious food for a child at any age. Depending on how old the child is when you wean them - you might want to consider raw goats milk, fresh juices, rice milk, almond milk - just about anything would be better than cows milk. Cows milk causes a lot of mucus, allergies and is not digestible.