are they going to make tefilin out of the hide?
I don't know about the cows, but I think the guy running the shechita (if my assumption is right that this is the same guy) once told me that when he does lambs they use the hide for klaf.
-unless I'm misremembering and he said they
don't use it because the animals are the wrong size. What I remember for sure is that he said there's a specific weight range that they make klaf from.