Barbed wire is your best bet.
Before, ranchers and farmers did their thing on huge plots of land. Wayward cattle often cause problems for both ranchers and farmers. For farmers, the cattle could come in and eat crops. For ranchers, cows could disrupt cattle raising and cattle driving.
When barbed wire was invented, many took they opportunity to fence off plots of land for their own use, signifying ownership of property. Ranchers and farmers often fought with each other for property, since both would need a large plot of land to do their thing.
