Mineral/Vitamin Supplementation: It’s Just Common Sense
Part I

 By WHITETAIL INSTITUTE STAFF

Have you ever heard someone say, “Why don’t you just use a little common sense?” It seems in today’s society common sense ¾ or the use of common sense ¾ is somewhat of a forgotten art.

For example, if you get a cup of coffee at a fast food restaurant, you can see the steam rising from the cup and the outside feels warm. Common sense would tell you that the contents of the cup are hot and it would not be a good idea to spill it on yourself. However, as you well know there is now a warning label on the cup telling us that the coffee in the cup is hot.

Common sense is not foreign to nutritional management of deer, either. One would expect that the better nutrition a deer receives, the healthier, heavier and bigger the deer will become at maturity. While this is commonly accepted in terms of the use of food plots, there has been some question as to the effect or need for mineral/vitamin supplementation for whitetail deer. To address this issue we are going to begin a three-part series that will take an in-depth look at the use of mineral/vitamin supplements in whitetail deer management. We will look at the arguments on both sides and, using common sense, come up with some answers to these questions.

Why is there a question of whether deer benefit from mineral supplementation? The question stems from the fact that conducting research on wild, free ranging deer is very difficult. This is especially true for establishing nutrient requirements. In order to establish nutritional requirements, two separate groups of deer must be used that are consuming the exact same diet. Then one nutrient is altered in one of the groups of deer.  This is called the test group. The other group, the control group, remains on the same diet. 

After a period of time, both groups are tested and the results show whether the group fed the higher level of test nutrient performed better. This test is repeated until a nutrient level is established that produces optimal results. This test is difficult with penned deer and nearly impossible with wild deer. The obvious problem with conducting this test is that you cannot make a wild, free ranging deer eat a specific diet. While tests may show a positive trend, acquiring enough data to achieve a statistically significant result is nearly impossible. Because of this, some people argue that mineral/vitamin supplementation of wild deer has not been statistically proven to show benefit to deer and, therefore, is not a valid practice. 

The other side to this argument is that for a number of years literally thousands of people have seen improvements in the wild deer they harvest after starting a mineral/vitamin supplementation program. Many independent research projects including those done at the Whitetail Institute of North America have shown dramatic improvements in antler size, fawn growth and survivability, and increased body weights in all classes of deer when a mineral/vitamin supplementation program is utilized. 

Just because statistical data cannot be acquired does not discount the fact that in almost all cases, mineral/vitamin supplementation results in bigger antlered deer. I like to compare this argument to the old question; “If a tree falls in the woods when no one is around does it make noise?” Because no one is there how can you prove that it makes noise?

Common sense says that obviously the tree makes a noise. In this three-part series, we will look at some of the common-sense reasons why we believe mineral/vitamin supplementation will benefit your deer herd.       

Part I – Mineral Functions and Antler Anatomy

To understand the need for mineral/vitamin supplementation in whitetail deer management, we must first look at how deer use minerals and vitamins. Minerals and vitamins have many functions in a deer’s body. The function most people relate minerals to is antler development. Indeed minerals are vital in antler growth. However, there are many other functions minerals and vitamins have in relation to whitetail deer.

One of the main functions is in skeletal growth. The skeleton of a deer can grow for the first 3-½ years of its life. During this time, the minerals consumed by deer such as phosphorus, calcium and magnesium, as well as others, are used to grow and strengthen the skeletal system. Furthermore, calcium and phosphorus are vital for does in milk production. The macro-minerals are not the only group of minerals important to deer; trace minerals such as iron, zinc, copper and selenium are also vital.

For instance, iron is essential for hemoglobin production and copper is important in important collagen production which is the protein found in antlers. Zinc is involved in DNA and RNA functions while selenium is important in muscle integrity. Vitamins should not be left out of this discussion either. Vitamin A functions in epithelial tissue integrity, vitamin D is necessary for proper calcium transport and vitamin E is essential for proper reproduction. This is only a glimpse at the literally thousands of functions minerals and vitamins have in a deer’s diet other than antler production. As you can see, adequate amounts of minerals and vitamins are absolutely critical for the optimal health and production of whitetail deer.      

As previously stated, antler development is the most obvious function of minerals and vitamins in a deer’s diet.  Let’s examine what antlers are comprised of and how minerals are involved: 

An antler is basically an extension of the skeletal system. It is in essence, an extremely rapidly growing bone. In the spring, hormonal changes in a buck cause antler buds to form. Rapid growth of the antler occurs over the course of the next few months.

During this time, minerals and vitamins are performing many functions. Iron is functioning to produce blood that supplies the growing antler. Copper is functioning in collagen production, which forms the protein matrix of the antler. Minerals such as calcium and phosphorus begin to deposit in the antler giving it solid structure. Toward the end of summer, increasing amounts of minerals are deposited as the mineralization process increases in rate. Eventually, all of the blood is cut off from the antler; the velvet dries and peels, revealing a solid bone antler. This hardened antler is comprised of approximately 55 percent mineral.

The mineralization process is a form of osteoporosis. Osteoporosis is the depletion of minerals from the skeletal system. When a deer’s body begins depositing large amounts of mineral to the growing antler, much of the mineral comes from the deer’s skeletal system.  The deer must then replenish the mineral lost during the osteoporosis process. 

An incredible amount of mineral is needed to produce antlers. If a set of antlers weighs four pounds, more than two pounds of raw mineral is needed to produce these antlers. This is on top of the mineral needed for all other bodily functions. This adds up to a huge amount of mineral required; the bigger the antler, the more mineral needed. 

It is argued that natural forages contain all the minerals needed for antler growth. This statement is true in that natural forages may contain minerals and vitamins that will produce antlers. The question, however, is do they contain enough to produce optimal antler growth? Furthermore, do they contain the right types of mineral needed and are these minerals highly digestible or will the deer be unable to properly utilize the minerals?

We will address these questions in greater detail in later segments; but in many cases, natural forages may not supply enough minerals or enough of the right types of minerals for optimal antler growth. This is the same reason cattle farmers have used free-choice minerals for years to supplement their cattle. Keep in mind, too, that cattle don’t grow antlers and require fewer minerals than deer, which makes supplementation of minerals to deer all the more important.

The reason adequate amounts of minerals and vitamins are needed to help ensure optimal antler growth is that antler growth is always secondary to body health. If the minerals and vitamins available to the deer are in low amounts, they will use these first to maintain body health and whatever is left over will go toward antler growth. 

For instance, bucks will use nutrients to regain lost body weight in the spring before the nutrients are used for antler growth. Common sense tells us that deer will not allow their skeletal system to suffer extensive osteoporosis if mineral is not available to ensure replenishment will occur. Again this is not proven, but is simply common sense.

As previously mentioned, does require high amounts of mineral for milk production. A doe’s milk is much richer in nutrient content than cows’ milk and lactating cattle are supplied huge amounts of supplemental minerals. Common sense would tell you that a doe would need mineral even more than the dairy cow. Also, fawns need mineral for skeletal growth. Because of the rapid growth of young deer, high amounts of mineral are required.

As you can see, proper amounts of minerals and vitamins in a deer’s diet are critical for optimal health and production. If your goal is to produce high quality deer, it only makes sense that ample amounts of the highest quality nutrition are needed to produce high quality deer. 

In the next two issues we will look at other common-sense reasons for using mineral and vitamins supplements in your nutritional program. Until then, don’t spill hot coffee on yourself. Just use a little common sense.