Corn silage and DDGs can make a great grower diet, maybe a little high in energy if you want to keep them green so you could free choice some low cost grass hay along with it.  Sample your silage and get it checked, there is a lot of low protein corn silage this year with the high yields.  4-5# of DDGs will go a long ways.
The balancer brings in calcium to balance the high phosphorus level of the DDGs.  It also brings in trace minerals and vitamins and Rumensin or Bovatec.