Would there be perhaps less feed grown if cows were supplemented with other feed? If 20% less of the cows' calories come from methane-producing sources, 20% le

Would there be perhaps less feed grown if cows were supplemented with other feed? If 20% less of the cows' calories come from methane-producing sources, 20% less land/duty cycle is needed for cattle grazing/growing feed, so other things can be grown or don't get cropped as quickly.