That's the way it is by me (another Wisconsonite (southwest)). Face each other at the property line and you're responsible for the right half. There's been legislation to change that. So far it's been defeated, but eventually it will win. The law as it is makes sense for farmers, but for recreational property, it's a waste of money (for the rec owner).
I argue this with my inlaws all the time

They're retired dairy farmers and I'm a recreational (hunting) property owner. It doesn't seem right or fair to force me to put up fence to keep YOUR cattle on YOUR property.
On my land, I have two rec owners and two farmers as neighbors. Between us rec owners, the fence is down (posts in, wire rusted, busted, down) and between me and the farmers, I have to keep up fencing to keep their cows in. BTW, I get along great w/ the farmers, hard working good guys! I just disagree with the law...