S.E.
My son started on regular milk at 6 months. Our Doctor said that was Ok and told he is 17 years old 6' 2", tall 185 lbs , senior in high school, very much into sports and very healthy. Our doctor told us that back in the earlier history of the country they did not use formula and if they did not have a goat they had to use cow milk. Goats milk is already pasteurized when it comes out of the animal and is actually better than cow milk for young one but I did not learn that till our son was older.
Maybe he is telling you it is time to switch. Unless he has health issues where he needs formula not all children need formula for a year. I know you will never get a pediatrician to give you the go ahead that is why we chose a D.O for our son and he still goes to him today.
Good Luck, S.