Well, not very. The usual agricultural practice for dairy cows is to take the calves away so that they're not consuming the mother's milk (because you want the milk; that's why you're keeping them in the first place). Female calves become more dairy cows, but male calves are pretty much useless, so you eat them.

So chances are you'll have prepared veal from the male calf at the same time as its mother is producing milk.

I've never been certain what this law was for. Most religious food practices stem from food hygiene laws; unclean animals are usually riddled with parasites, kosher and halal killing practices codify particular (safe) ways of slaughtering animals because otherwise people wouldn't do it properly --- but this one? Dunno.

> I've never been certain what this law was for. Most religious food practices stem from food hygiene laws;

This is a made up explanation by people trying to fit religion into their worldview.

But actually the kosher laws have no reason, God simply said to do them, and that's it. We keep them because God asked up to.

There are some laws God gave reasons for, but Kosher is not one of them.

The laws of kosher are actually used as an example of a law that we don't know the reason. It is kept only because G-d commanded.