Most milk did not have the 400 IU of vitamin D - 1992

And much of it at the time was vitamin D2

PDF is attached at the bottom of this page

Infant formula 40 to 100 IU of vitamin D per 100K Calories

FDA

Apparently need 100K calories per kg, which is 454 K calories per lb

So, a 10 lb baby getting 4540 K calories of formula would get 182 to 454 IU of vitamin D

Every 2-oz. of Similac Advance contains 60 IU of vitamin D

See also VitaminDWiki

• Low fat (e.g. skim milk) provides less Vitamin D – May 2016