Each time a feral hog crosses a property line it changes ownership. A branded/ tagged cow never changes ownership, a cow is livestock and different laws apply.
Here is another scenario and is really the way it goes. My friend calls me and tells me to load my dogs; there are hogs in his hay field. So we get there, turn dogs out, hit a hog that runs four fences south onto another property. Now does that hog belong to that land owner or the one where we started the hog??? Same scenario with one of his cows, which can and does happen, does the cow now belong to the other guy??? If your cow gets out and causes property damage you are liable!!!!!!