About every bull test has a different ration. Some higher roughage, some not. Depends on how you want the bull to grow. Moderate growth ready to go to work, to heavy for the yearling weight. Some feed to much barley = feet that blow out. Some use a feed companies pellets/cake and bull growers formula. Some use silage and hay.
I haven't heard much good from one of the big feed companies products. To much fines. In fact I won't buy their products (mineral or cake) for my cows. It maybe cheep but it isn't worth beans.
Best would be to look up all the feed companies in your area and have them give you a guaranteed ingredients sheet. Make sure to not have any fines.