Cows are mammals and we now do know that we, as mammals, share a common trait which is we love our children so much because it’s an evolutionary advantage for the survival of our species.

So in your scenario, either cows will suffer from giving birth to brain dead children, or at least, not different from today, because we take their children to get their milk.

Brain dead mothers would be ethically ok to me but … that’s really a really strange thought and I feel that there would be unknown issues like how could you know that your cow is sick like a full bag of bacterias if the cow is not showing suffer ?

What an a odd topic.