Since I used to work in deer and turkey management, and fed both corn and raw soy beans by the truck loads, let me tell you what I have seen. Kaye is very close to my way of thinking about the deer corn. The deer corn usually has a lot more "trashy" stuff in each bag, and for the most part is usually a low grade of corn. Now some years the deer corn looked just as good as feed corn, but most often that is not the case. I doubt that a little of the deer corn would kill your goats, but for a buck more a bag, I would rather buy the good stuff.
There is an old saying around here with old timers who raise goats..." a little bit of corn goes a long way" ....meaning that if they feed corn at all, it will be only a few grains per feeding, mixed in with there other grains.
I did some research a few years back on corn and deer......and many biologist came to this conclusion about feeding corn as a primary feed.....they claimed that if you put a deer in a pen, and fed him nothing but corn and grass hay, that they would starve to death.
I can tell you first hand, that when we were using the mostly corn as a supplemental food for deer, that I saw very little increase in the size of bucks racks, or the overall healthy appearance of the deer. Most deer that were harvested did have a good padding of fat atop their hips, and a good role around their gut. We really didn't see any big improvement in the herd until we dropped the corn and started using the raw soy beans. The change was so drastic, that it was very noticeable within the first year......huge racks, hair that looked like it had been waxed, color that was pronounced. The bucks when in rut, looked like they were on steroids or something.
Seeing this made me draw the conclusion pretty quick, that the corn just wasn't much of a benefit at all, other than the fact that the deer would really eat it well .