Whole corn might be cheapest option up front, but the amount actually utilized by the calf is less than if you at least crack it or grind it. Introduced into the body in the form the body can use easiest gives the most percentage of gain for your dollar. If you are going to feed whole corn, I would suggest running a batch of chickens with the calves so you can raise some great poultry at the same time on the same corn, only the chickens get it after it has been softened in the calve's intestines. Figure out how many pounds and how many days you will be feeding, then check with a few feed suppliers even a local farmer that grinds his own feed, you may be able to purchase a lot cheaper and in a more useable form by buying in bulk. It will not spoil so easily that time of the year as it would in August.