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Providing high-quality supplemental feed can greatly promote nutritional health in deer, and in some cases increase antler growth in bucks — but only when age is not a primary limiting factor.
It’s no secret that deer, like other animals, must have access to adequate nutrition in order to maintain good overall health. And deer managers often focus much of their efforts on ensuring that a deer’s basic nutritional needs are exceeded to promote healthy herds and large-antlered bucks.
Although there are a variety of ways to enhance the available nutrition for deer, including native forage management and establishment of forage plots, supplemental feeding is perhaps the most controversial and least understood option. In this article, I will cover everything from the specific nutritional needs of deer to the potential problems associated with feeding deer in order to help you better evaluate the role of supplemental feeds in your deer management efforts.
Deer Nutrition 101
The first thing to recognize about deer is that they are a ruminant. Like cows and sheep, deer have a four-chambered (rumen, reticulum, omasum and abomasum) stomach where food is broken down by microbes and nutrients are absorbed. However, while most livestock are considered grazers, white-tailed deer are browsers, and this distinction is important for nutrition.
The rumen of white-tailed deer is proportionally smaller than those of most livestock, which makes them better suited for digesting the leaves and stems of woody plants and forbs than long fibrous grasses. In fact, the only grasses deer heavily utilize are those that their body can breakdown rapidly, such as small grains (wheat, etc.) used in food plots. Even small grains become less valuable to deer once their blades mature and become too fibrous for easy digestion. More on that later.
All of the food a deer takes in can be placed into one of five general categories: protein, energy, minerals, vitamins and water. Protein is very important for body and antler growth and frequently is the most limiting nutritional factor for deer. Deer must take in about 7% protein to maintain normal bodily functions, but protein levels of 16 to 18% are considered optimal. The specific energy requirements of deer will vary widely across seasons and age classes.
Carbohydrate-rich foods, such as corn, are typically considered good sources of energy for deer, but cellulose is also a carbohydrate and serves as the primary energy source for white-tailed deer and other ruminants.
The roles of specific minerals and vitamins in deer nutrition are less understood than protein or energy. We do know for sure that calcium and phosphorus are extremely important to growth and antler development in deer. Male deer mobilize bone reserves of calcium and phosphorus to grow antlers each year, and these reserves must be replenished though adequate dietary intake.
Vitamins can be grouped into water-soluble (e.g. vitamins B and C) and fat-soluble vitamins (e.g. vitamins K, D, A and E). Most experts agree that sufficient levels of water-soluble vitamins are actually produced by the microbial activity in the rumen to meet nutritional requirements. In terms of fat-soluble vitamins, vitamins A and E are the primary ones that could be limiting nutrition.
Deer produce vitamin K in the rumen and synthesize vitamin D during exposure to sunlight, so these vitamins are not of concern. Although vitamins A and E are abundant in green vegetation, there is some evidence that supplementing these vitamins could benefit antler growth and general deer health when these types of forages are not readily available.
To Feed or Not to Feed
First and foremost, the decision to feed deer is often dictated by state wildlife regulations, which vary widely from state to state. Some allow feeding year round, others only outside of hunting season, and some not at all. Although the ethical implications of supplemental feeding relative to hunting have historically driven deer feeding regulations, the spread of chronic wasting disease (CWD) throughout much of the United States has driven policy in recent years.
If you don’t already know, CWD is a disease found in ungulates, such as white-tailed deer, elk and mule deer, that is the result of altered proteins (prions) most commonly present in the central nervous system. The disease is 100% fatal and there is no known cure. CWD is a transmissible spongiform encephalopathy (TSE), and although there is no documented case of a human contracting CWD, many researchers are quick to warn that the disease could pose a concern for human health if it were to somehow change and “jump” to humans.
We know that deer contract and spread this disease by coming into contact with an infected deer or the saliva from an infected deer. Concentrating deer at a feeder could promote the spread of the disease, hence the effort by many states to restrict deer feeding.
You might be wondering why food plots do not come under the same critique as supplemental feeding in regard to the spread of CWD. The suggested answer is that food plots do not concentrate deer as much as supplemental feed, and actively growing forages are elevated from the ground, which helps to minimize the exchange of saliva between deer. I’m not sure that we really know what role food plots might be playing in the spread of CWD, and my opinion is that the decision to regulate supplemental feeding and not food plots is more related to our ability to enforce regulation than science at this point.
Assuming that feeding deer is legal in your state, the decision to feed becomes a question of cost and benefits. Along these lines, it is first important to consider the intended purpose of a feeding program. Are you trying to improve the overall health of the deer herd or are you simply trying to attract more deer to your property? While these two agendas are not necessarily mutually exclusive, it helps to have a clear picture of your intended objectives so that you can make a realistic plan and evaluate success. All too often deer managers will take on a costly feeding program with the hopes of growing record-book bucks, only to realize that the factor limiting antler size was age and not nutrition.
The quality and quantity of forages is extremely variable according to the location of the property and the season. Consequently, some landowners receive greater benefits from feeding than others. By no means am I trying to discourage a supplemental feeding program, because they can have great benefits under some circumstances. However, take some time to evaluate the specifics of your property before jumping in to ensure that you are not setting yourself up for disappointment.
One fact that holds true across properties about supplemental feeding is that it is a surefire way to ensure that high-quality nutrition is available. Although food plots and native plant management can do much to improve available nutrition, inevitably there will be periods when growing conditions are poor and quality forage might be limited.
In fact, some of our recent research here at Auburn University suggested that supplemental feed was a more cost-effective way to ensure optimal levels of available protein during stressful late-summer periods than food plots and burning native vegetation. While providing feed year-round might be of some benefit on your property, be sure that your efforts specifically target periods of low nutrient availability to ensure the greatest results.
Selecting the Right Feed
It is important, once again, to consider the purpose of your feeding program and your specific conditions when selecting a feed. If your goal is simply to attract deer to your property, there probably is no more cost-effective or better option than corn.
For those who are interested in providing a high-protein food that promotes deer health and antler development, landowners frequently turn to an agricultural crop such as soybeans or peanuts, or a manufactured deer feed. My opinion is that the added benefits of high-quality deer feeds are worth the expense when compared to feeds such as soybeans. Deer feeds are typically a complete ration, meaning that they have added vitamins and minerals, which can be a great benefit over some forages.
Be sure that when you are selecting a feed your decisions are based on the information on the guaranteed analysis tag and not the celebrity or big buck on the front of the bag! All deer feeds are not equal, and you should be very critical of the specific contents of what you are buying. There is no regulatory body that governs what can be put into deer feeds, which means companies could literally put old shoes in feed if they wanted.
The first thing to look for on the tag is to make sure that the first ingredient is “Grain Products.” This is not to be confused with “Processed Grain By-products.” Grain products are the actual grains, such as soybeans, whereas processed grain by-products can be literally anything left over from processing agricultural products.
A sure give away that a feed has a high content of these by-product fillers is a fiber content greater than 12%. Remember that I said deer have a harder time processing extremely fibrous forages? Although some grain by-products might be high in protein, these proteins might not be in a highly digestible form for deer, and thus rather inaccessible nutritionally, due to their high fiber content. Also, be cautious of deer feeds that are produced using low-cost formulation. This simply means that the producers are using the cheapest products available at the time of production to keep cost down, which translates into a lot of variability in the end product.
Assuming that the protein is from a highly digestible source, protein content should be 16 to 18%, with no real benefit in higher concentrations. The volume of calcium will usually be double that of phosphorus, and the total volume of both minerals will be relatively low. Most feeds will have adequate levels of these minerals because they are pretty inexpensive additions.
Although vitamins A and E are readily available to deer in most natural settings, individuals involved in the captive breeding industry report increased antler growth from additions of the vitamins when deer don’t have access to lots of green vegetation. It’s expensive to add vitamins A and E, so feeds with these components will be sold at a premium price.
The final considerations when selecting a feed are not related to nutritional content, but rather other additives that control parasites and preserve feed. Parasite control can be in the form of a repellent, such as garlic or sulfur, or a pesticide that usually targets worms. I don’t see any harm in feeding products with insect repellents, because minimizing parasites, such as ticks, could promote good animal health. However, I would discourage the continued use of these products, because consistent use can encourage the development of pesticide resistant organisms. Feed coatings that repel moisture and improve the life of the feed are not harmful so long as they do not interfere with nutrient digestion and absorption.
Delivering the Goods
The type of feeder used for supplemental feeding is largely dictated by the type of feed you intend to use. Spin feeders are best suited for dry grain products, such as corn. Pelletized deer feed does not typically work well in these feeders, because it tends to attract moisture and is prone to clogging spin feeders. Manufactured deer feeds are best fed out of a covered trough or gravity feeder. I prefer gravity feeders, because they reduce spoilage as compared to troughs.
Further, many gravity feeders are configured in a manner that makes it difficult for non-target animals, such as raccoons, to get to your expensive feed. This is extremely important, because feeding raccoons and other non-targets can double the cost of your feeding program if you’re not careful. The big things to consider when evaluating gravity feeders are: 1) make sure they have adequate numbers of ports to feed multiple deer at one time and 2) the materials used in construction are adequate to stand up to years of exposure to the elements and feed with a high salt content.
Conclusion: Food for Thought
Providing deer with access to high-quality supplemental feed can greatly aid in deer management efforts in many areas where feeding is legal. However, feeding will translate into the greatest tangible benefits for hunters, in terms of increased antler growth in areas where buck age is not the primary limiting factor and nutrients are somewhat limited. Carefully consider the overall goals of your feeding program and how to best incorporate feed, especially during times of lower forage quality or availability. If you plan to use a manufactured deer feed, critically evaluate the product you are buying based upon the previous guidelines to ensure you are getting the best value for your money.
Author’s Note: AntlerXtreme deer feeds, Fort Valley, Georgia, provided insight on feed selection for this article and is the exclusive provider of feed for the Auburn University Deer Research Facility.
— Chad Newbolt began working with the School of Forestry and Wildlife Sciences, Auburn University, as a Research Associate in 2007, and has since assisted with various wildlife research projects throughout the United States and abroad. His main research interests include white-tailed deer reproductive ecology and improvement of deer census methods.
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