I think there's a definition confusion here. "Pregnant" means fertilised but had not yet given birth. After an animal gives birth, they are no longer pregnant. If an animal only produced milk when it's pregnant, then it would never have it at the right time for it's offspring.
I think you had meant to say "... if it has been pregnant recently". That's why there are so many confused replies to your comment.
I think there's a definition confusion here. "Pregnant" means fertilised but had not yet given birth. After an animal gives birth, they are no longer pregnant. If an animal only produced milk when it's pregnant, then it would never have it at the right time for it's offspring.
I think you had meant to say "... if it has been pregnant recently". That's why there are so many confused replies to your comment.