The land that Bundy is trespassing on and claiming squatters rights to is US federal land. There are no states rights issues here.
Federal lands comprise about 85% of Nevada so he probably isn’t alone. If the cows are such a threat, looks to me like the blm needs to round up all the horses currently “trespassing” on federal lands as well. Either that or shoot them from choppers and let the predators dine on their carcasses. Animal rights activists would have a field day with that one. After all, they, like cows, are imports to the US.