It is the water rights that are 'titled' on public land. If you have the water rights, you also own grazing rights on enough land to utilize the water.
Strange proposition for an Easterner, but it comes from Spanish law that was in place when the Hidalgo Treaty was signed, and remains so until today.
By law, it cannot be changed, but Agenda 21 and our Progressive Gov't will eventually eliminate all of the rights holders, resulting in the end of Western ranching.
Nevada has grazing easements that are partially based on cow trails and historic use. These laws prohibit fencing that would impede the cattle’s movement - even if you own some land, if someone else owns the grazing easement, you can’t put up a fence without his approval.
Anyhow, this way of defining grazing rights is actually tied to water as well, since the trails lead from grazing to water.