There is corn gluten meal which is sky high in protein and is almost always mixed with other stuff to make it more balanced.
CG pellets are lower in protein (I think running it through the press heats it and cooks some of the protein out, just my theory) and it can be fed either by itself or mixed in a ration to increase the protein content. We had palatbility iossues if the CG pellet was approchaing 50% of themix and when we fed it straight. You don;t want to stand behind a cow that's eaten the stuff if she coughs, it's like the spring grass squirts