The owner of any livestock in this state shall not be liable to the owner or his agent or [of] any mining or mineral claim or millsite for damages done by way of trespass upon the same by said livestock other than for actual damage done to buildings, tents, mining supplies or other personal property situated thereon: provided, that nothing in this section shall be construed as abridging or curtailing any of the existing rights of any such owner whenever any such mining or mineral claim or millsite may be used by the owners thereof, his tenant or lessee, as a livestock ranch.