Since there are no studies showing mineral supplementation benefit free ranging deer, we are dealing more in opinion than fact when it comes to mineral supplements. So, the most cost effective minerals are those that are used in a way that have a proven benefit to deer. I'd start by doing a soil test and then plant a food plot and apply the minerals P, N, and K along with any trace minerals as called for in your soil test. We know that when these minerals are applied to deer food, not only are the minerals delivered to deer, but they improve the nutrition and energy provided by the crop.
If you look at a deer's diet, you will find that most of it comes from native vegetation. The each plant species has different properties when it comes to mining minerals from the soil. With the wide variety of native plants available to deer, short of disease or genetic defect that causes an inability to absorb a particular vitamin or mineral, you really won't find free ranging deer herds that have a mineral deficiency. Only when deer are penned or their diet is otherwise limited do we see studies that show benefit from mineral supplementation.
On the other hand, there is plenty of data to show how improving the quality food supply during periods of high stress can improve the health of deer. Also, keep in mind that when mineral supplements are delivered as point source attractants (licks, blocks, etc.), they do pose some level of increased spread of some diseases due to an increase in face to face contact.
I tried licks years ago to help inventory bucks. I found there were better ways to accomplish that without the risk and eliminated mineral/salt licks from our program completely.
Thanks,
Jack
