Feed a blend if ya can. I prefer corn but that's just me.Most assuredly keep salt available free choice. I prefer bagged mineral which I provide in abundance, but some believe in blocks for their convenience.
We like to feed an 18% medicated starter/ grower. Has a blend of more corn than oats they grow good on it.Like Rookie said, loose minerals are my choice as well. just a matter of preference, with blocks or loose.
For my feedout calves over 5 wt I use 60/40% whole corn/oats. with some loose mineral thrown in. Free chioice mineral blocks and hay (or pasture) also available. Corn alone may cause acidosis depending on amount fed.