I recall a very old sci-fi story in which bored scientists at a remote space outpost, well, some of them really missed milk. So they decided to try to produce

I recall a very old sci-fi story in which bored scientists at a remote space outpost, well, some of them really missed milk. So they decided to try to produce it. But then that needed some kind of circulatory system to support the udder, and that required a filtration system, and an oxygenation system, and a way to get nutrition into the circulatory system ... They ended up building a kind of exploded steel cow, all pipes and vats and such. It seems we are heading in this direction. I have often wondered what it would be like to start with a cow, then engineer it to be anencephalic, then start paring away "features" or moving them around. Skip the legs, but do have networks of heart-like cells providing a contractile rhythm for the muscles, and so on.