In the 'good old days', at Michigan state University, pre-vet students were required to take a poultry science class, and livestock nutrition. Before hand held computers, all arithmetic done by hand.
No idea what's required now!
My point is that it's better to admit not knowing, rather than...
Two comments here: @SilverBirds misspoke about protein level in scratch feed, it's low, not high.
And this veterinarian should know when to say "I don't know" rather than making something up! I just hope that this person was misunderstood, but if that was the advice given, awful!
Mary