You'll need something like 3,151,600,000 Acres of fair quality grazing land, and funny you mention that because I recently heard news of people putting into place a plan sort of like yours, image attached below.

Look, I'm not telling people to give up meat. I love meat. I'd buy the bulk burger and freeze most of it without a second thought, turn some into my specialty summer sausage to share with friends and family. But I think people should be conscious of the costs of the meat and limit their intake.