Well, you have had confirmed panther sightings, tracks, bodies all over the state of Iowa for the last 15 years. You have had the same from one end of Illinois to the other over the last 7 or 8 years. So, i dont think panthers showing up in any part of Wisconsin should come as any great surprise.
Once you get any stable population of panthers in an area, and they figure out that a cow is easier to catch than a deer, i think that you are gonna hear more stories like this.