MONITOR VALLEY, Nev.—Wayne Hage saddled up to check on his cattle one morning last summer, but he didn’t have to ride far. All his cows were confined to a private field near his ranch house, instead of roaming the Toquima and Monitor mountains, as herds have done for more than a century.

Federal officials have prodded Hage cattle off this lonesome stretch of central Nevada. They didn’t use a lasso. The government corralled the cows through a series of court rulings and policy changes to limit grazing—tactics applied broadly...