oomis: the premise to be lenient on powdered milk is that it is physically impossible to make from non-kosher sources. That is clearly no longer true! “
I think that refers to cheese, not to powdered milk (although I am hearing it is no longer true about cheese, either). Why should there be any difficulty in making unkosher powdered milk from ANY source? The water in the milk is completely evaporated through a process, and what is left is the powdered residue. It is reconstituted with water when needed (i.e. to feed a baby horse or csmel).