It is merely the absurdity of the situation. Cow parents raising their calf to be accustomed to the electric fence just as they are thereby training it to be a proper cow. Just silly. Far Side hits like that for me. Sometimes the absurdity resonates and sometimes it does not. Even for me and I love it. Probably because most of them resonate for me. I love absurd humor. My paltry explanation likely won’t make it any funnier for you, but hopefully it helps you understand why I find it funny.

Me every time I see one of these pretty much.
Feels like these are from another timeline. Guess the name is fitting.

If I had to guess, I think this might be poking fun at overprotective parents who unwittingly do more harm than good by controlling their kids’ environment to an unhealthy degree.
Trying to read more into it, perhaps it’s also pointing at the propagation of bad childrearing practices across generations - parent cows grew up on a farm, constrained by an electric fence. Though presumably more independent now, this is what they knew growing up, so they apply (a bizarre perversion of) these same practices to their own children.

I’m probably way off though, because that interpretation barely elicits a half smile from me.
Curious for an explanation from someone who actually gets it too.

It’s a crib with an electric fence