We just held (slowed down) a steer by replacing 2/3 of his feed with a beetpulp mix, he did just fine, I did have them add protein (calf-manna) just to keep him fresh,
He was getting 6 pounds of grain, 14 pounds of a beetpulp, oats, cotton seed hull pellets mix, 2 pounds Calf-manna, 2 pounds Stabilized Rice Bran, did not hurt him a bit.
We have just fed the beetpulp mix strait as well and did not effect them at all, they still gain some just not near as fast.
I do not see why you could not cut the corn in half and add beetpulp to replace it.