The land required for industrial non-meat food production has a lot stricter requirements then grasslands. Just replacing them is not possible. In practice a lot of agricultural land is coming from cleared forests and leaves behind eroded soil which is a giant problem. You can keep cattle (or Bisons it seems) on those. With the added benefit of them actually rebuilding the topsoil.

We might actually need something like this.

edit: Then again, bisons are fucking scary. There is a great story i read a while back about the huge starting advantage Europe had vs Africa and America when it came to easy to domesticate animals. Good luck trying to survive riding a Zebra or hunting a Buffalo.

On a sidenote, there is an Island in Africa created by a river which trapped a bunch of Lions and Buffalo. Lions had to evolve to incredible dimensions to hunt successful. Search for Okavango Delta