Grass-fed beef is no real solution to the grain shortage. For one the meat is more expensive, for another there is a limit to the land that can be used as meadows but not for other crops.
There's a reason why cattle farming went from extensive to intensive methods.
And it anyway affects only the US, a very small fraction of world population or land area. That the US is a very large part of the problem, e.g. importing beef, does not help.