I visited my local tannery this morning. It was a real privilege to be given a quick tour of the factory by the boss. I bought a hide and they will be splitting it into 2.5mm, 2mm and 1.5mm sections at my request and then delivering it to me.
I asked the boss what happens to the skins from cows which become 'Kobe beef'. He told me they are no good for leather working. The hides they process are from milkers.