I hadn't planned to use formula at all and had NO idea that it was based upon cow's milk. My son was so fussy that I couldn't stand to try to nurse him because he would wiggle and cry and fuss. I gave him a bottle and within a couple of minutes I noticed that the bottle was leaking.
I took the bottle away and began taking off his clothes to clean him up and he was nothing but red welts where the formula had come into contact with his skin. He'd only had the bottle a few minutes! I cringe to think what it must have been doing to his tummy!
I got used to reading that fine print on the table of ingredients on food labels and learned the "buzz words" that translated to cows dairy products - most specifically the protein component:
Whey
Casein
Lo and behold I did manage to find an obscure baby formula on the market that had NO cows dairy components in it whatsoever. It was only slightly more expensive that the more common ones typically found on the grocery store shelves. I kept a supply of it on hand for emergency use only.