The only reason not to switch to cow's milk would be if there was a dairy intolerance or allergy which you would know about by now!
Stage 2 and 3 formulas or toddler milks as they are sometimes known are basically a marketing ploy. The formula manufacturers can't advertise first formulas (birth plus) or put offers on them so they have made different formulas for 6 months plus and toddlers to get around that. If a toddler is getting as varied a diet as they will allow (
![Tongue :P](https://smiley.babywhispererforums.com/Smileys/classic/tongue.gif)
) there is no nutritional need for it.
You can transition by swapping formula for cow's milk oz by oz. For example if he has a 6oz bottle you make up a 5oz bottle and then add 1oz of cow's milk, after a couple of days you can swap another oz of formula for cow's milk and so on until it's all cow's milk. I did this with both mine and they adapted well, if he doesn't like milk to drink then add as much dairy to his food as you can.
Laura