DS is almost 14 months old.

He has been on formula since he was born.

At one stage he liked the cows milk, and wouldn't drink formula. Then it started giving him pains, so we went back to the formula.

Now Im trying to get him used to cows milk, so after Ive made up the formula, I add a bit of cows milk in. When I do this, he still gets the pains.

He won't drink milk or water from a sipper or normal cup, but is sometimes happy to drink water from his bottle. He is only having 2-3 bottles a day of formula, and the most he will drink is 150ml. He still has heaps of wet nappies, and is happy during the day.

He eats a variety of foods.

How can I get him used to cows milk and drink from a sipper cup??