Hi
My LO recently just turned one. Since about ten months her first bottle of the days has been cows milk and I usually split that with her cereal and then her last bottle of the day would be formula. Since switching her last bottle into a cup and now being completely on cows milk she is waking several times through the night. Before this she was sleeping through the night. She started sleeping through from ten months which I thought was a coincidence with starting her on cows milk, but apparently not now she is completely on it.
When she last got weighed the health visitor told me that babies tend to wake in the night if they are not getting enough in the day, she has three meals a day, and she only 18 pounds at a year (she has always been small) so a lot of the time her appetite isn't that big with being so dinky.
Another thing I got told us that it could be an allergy that is causing her discomfort during the night. Or that the milk can be a bit harsh to start off with and it takes a little time for her tummy to adjust.
And other ideas would be grateful. She is having her jabs in a couple of days so I will be talking to the doctor about this if she is still not sleeping through