PORTLAND, Ore. — For weeks, rancher Darrel Holliday has rounded up frightened cows and calves off the smoldering hills of the Strawberry Mountain Range, a wilderness area in eastern Oregon of old-growth forest and grass where wildlife and cattle roamed.

Holliday’s entire federal forest grazing allotment of about 32,000 acres — 50 square miles — burned last month as a wildfire ravaged the area. The land is now a smoke-filled expanse of blackened tree sticks and ash a foot and half deep.

“We’re picking up cows that should have calves with no calves. We assume they might have died out there,” said Holliday, who is still missing 22 of his 180 cow-calf pairs. He’s among dozens of ranchers similarly wrestling with the loss of animals and grazing land in a region where cattle production is one of the leading agricultural industries.

The vast majority of the 1.6 million acres — nearly 2,600 square miles — that burned in Oregon, Idaho and Washington this year are federally owned, data show, with large swaths of that public land used as rangeland for livestock grazing.

Many of Holiday’s recovered animals have burnt hooves or are lame from walking on hot coals, he said. Miles of fences have burned. And the land, for which Holliday pays a fee, will likely be closed to grazing for at least two years while it recovers, he said.