why did cattle owners have to buy private property on which to keep their cattle?

Cattle owners had to buy private property on which to keep their cattle because public grazing land was becoming scarce, and the government was beginning to restrict access to it. This was due to various factors such as the increasing population, expansion of agriculture, and the need to preserve land, wildlife and other natural resources. As a result, private property became the only viable option for cattle owners to continue running their businesses. Additionally, owning private property provided owners with more control over their operations and greater security for their investments.