If humans were to quit eating/milking cattle because they produce methane no one would have any economic reason to raise cattle, perhaps other domestic animals either. I wonder would these domesticated breeds then be allowed to go extinct except perhaps for rare farm animal zoo exhibits because without animal products to sell breeding and raising them no longer pays? I doubt that's what animal rights activists had in mind, but would that then become the reality? I consider it a rhetorical question because I don't think it will actually happen.