Are Your Deer Hungry?

September 22, 2010 By David Morris

The latest buzz in the whitetail world centers around the impact of nutritional management — particularly the year-round use of food plots — on the number and size of deer a piece of land can produce.

Although that impact will vary by program and management intensity, there can be little doubt that the right nutritional approach makes a huge difference in the health of a deer herd. But unless you've seen the results of a sound food-plot program in action, you might question its amazing benefits. You might think that good native habitat or even supplemental (direct) feeding is equal to plots in providing prime year-round nutrition for the herd.

If this is your view, you might want to rethink that opinion. The following simple comparison of nutritional options illustrates how great an impact food plots can have on the size and number of deer available to hunt.

I don't hold out these numbers to be absolute; rather, they're intended to illustrate the relative nutritional impact of supplemental feeding over natural habitat and of food plots over either. Because of limited space, I won't try to explain every assumption and the reasoning behind it, but I've found that these numbers present a fairly accurate picture of what goes on in such management programs.

For purpose of illustration, I'll use percent of protein in a deer's diet to represent relative nutrition. I realize nutritional factors other than protein also are important; however, percent of protein allows us to use meaningful numbers for comparison.

NATURAL HABITAT

Not all whitetails in North America eat the same amount of food in a day. But strictly for purposes of illustration, let's assume that an "average" deer, given as much as it would like to eat, consumes 7 pounds per day. In a year, that totals 2,555 pounds.

Let's also assume that the natural habitat averages 11 percent protein on a year-round basis. (The general consensus among biologists is that whitetails need approximately 16 percent protein during the antler-growing/fawning period from early spring through summer. Eleven percent would be representative of quality native habitat such as is found in South Texas. A study in Alabama showed an annual average protein level of 7 percent in the natural habitat, which would be representative of much of the rest of the Southeast as well.)

Let's assume that an acre of natural whitetail habitat can produce 200 pounds of deer feed per year, but that only half of that (100 pounds) can be eaten without damaging the habitat. (In the Southeast, average production of native deer forage is closer to 150 pounds per acre.)

Using an annual production of 100 usable pounds of deer browse per acre of natural habitat and an annual requirement of 2,555 pounds of feed per deer, we see that 25.6 acres are required to support one deer throughout the year.

But remember: This is about right for good natural habitat - habitat that has a high protein level. With an average protein level of only 11 percent in the herd's diet, at a density of a deer per 25.6 acres body and antler sizes are going to be well under the herd's genetic potential. In addition, many (indeed, most) whitetail populations are underfed, due to excessive foraging pressure on the available vegetation. Put all of this together, and it's easy to see why we have so many stunted and stressed herds today.

Let's assume that a deer on decent natural habitat will eat no more than 25 percent of its daily diet in supplemental feed (high-protein pellets, cottonseed, dried soybeans, etc.). The only time I've ever seen deer eat more than about 2 pounds of supplemental feed per day is when they have degraded the natural habitat to the point that browse plants (including not just "ice cream" plants but also "subsistence" species) are of limited availability and quality. In such cases, the deer have no choice but to utilize supplemental feed heavily to get adequate nutrients.

True, whitetails can do well enough on supplemental feed, as evidenced by captive deer with no other forage options; however, they will only become dependent on such feed when forced to because of severely degraded habitat nearly devoid of natural browse. Deer are browsers by nature. Standing in one place at a feeder and eating feed is an unnatural act, and they will only do it in excess if forced to by the elimination of good browse options.

Let's assume that supplemental feed has 20 percent protein. With 25 percent daily consumption of supplemental feed and 75 percent of natural forage (at 11 percent protein), the average protein level increases from 11 percent to 13.5 percent. That's nearly a 25 percent improvement: much better than the natural habitat alone, but still well below the 16 percent level reputed to be the desired minimum for full body and antler growth.

Assuming that supplemental feed replaces 25 percent of the natural browse in the diet, logic says that the herd density can increase by 25 percent — to a deer per 19.1 acres — without a significant increase in browsing pressure on the habitat. Or, to look at it another way, if the density stays at a deer per 25.6 acres, the increase in the nutritional plane (as reflected by the increased protein level) would result in an increase in body and antler size. How much? Perhaps something along the order of 25 percent of what would be possible with ideal nutrition.

So with supplemental feed in poor natural habitats, we see real gains in both deer numbers and size - without, in theory, necessarily impacting the habitat negatively. And my experience with supplemental feed supports this theory. It can elevate the nutritional plane enough to boost size and allow more deer to be carried. However, the degree of improvement is incremental and limited without damaging the natural habitat.

One of the great benefits of supplemental feed is that it tends to help level out year-to-year and season-to-season forage fluctuations, which can be a real challenge in some parts of North America. Also, it can give managers without an agricultural option a way to improve the herd.

The danger of too much long-term dependence on supplemental feed is the temptation to increase deer numbers to the point that the natural habitat is severely degraded. This creates a damaged ecosystem, a situation unacceptable to any responsible deer manager.

AGRICULTURE

Now let's look at what for many managers is the most effective way to significantly elevate deer nutrition: an intensive year-round agricultural program directed toward the herd.

Let's assume that 75 percent of a whitetail's daily food consumption consists of prime agricultural crops, the other 25 percent of native browse. Such heavy utilization of food plots isn't theoretical; at North American Whitetail's Fort Perry Plantation in Georgia, agricultural crops make up 80 percent of the herd's annual diet. And under management, the deer density increased to more than five times that of natural carrying capacity - even as the health of the natural habitat steadily improved. In the West, whitetails in river-bottom habitat with irrigated alfalfa are almost fully dependent on that crop when it's available. The same trend is true in the Midwest and Central Canada.)

Here's the key to why whitetails do so well when provided with the right food plots: They view prime agricultural crops as browse, not as supplement. Depending on the quality of native browse and that of the crops, they will utilize the plantings almost exclusively, just as they would any other highly nutritious, highly digestible "ice cream" plant. To whitetails, items such as cowpeas, clovers, alfalfa, lablab, etc., are simply super forbs available in super abundance.

Let's assume an average (warm-season) agricultural protein level of 25 percent protein. (Cool-season crops, such as cereal grains, don't have — or need — that level of protein, but we're speaking in relative terms. And some food-plot plants average in excess of 25 percent protein, particularly in the growing tips deer favor.)

At 75 percent agricultural consumption of 25 percent protein and 25 percent natural browse consumption at 11 percent protein, the herd's average protein intake is 21.5 percent. And even at 20 percent average protein for agricultural crops, at this level of utilization the average protein level still is 17.75 percent. (The impact on deer numbers and quality at these relative levels is obvious and dramatic.)

With 75 percent agricultural consumption, logic dictates a corresponding reduction in browsing pressure on native habitat, allowing herd density to increase from a deer per 25.6 acres on native browse to a deer per 6.4 acres on agriculture — without increasing pressure on the natural habitat.

Looking at the above numbers, it's easy to see that deer size and numbers can be significantly increased through the proper use of agricultural plantings. In fact, under intensive agricultural programs, it's possible to carry two, three or even more times as many deer as natural habitat alone can support, and for those deer to be bigger than they would be if feeding on native habitat alone.

The key to achieving these agricultural gains is intensive farming that consistently produces the necessary crops. Of course, that isn't something every whitetail manager is willing to do or capable of doing. It's a big commitment in every sense, but it's possible.

Huge gains through agriculture are more than theory. They're now being enjoyed by deer managers in many parts of North America — without damaging the habitat. And the beauty is that as a manager you can choose your level of management intensity based on personal goals and resources. For most of us, some combination of natural habitat management, supplemental feeding and agriculture is a logical and feasible way to go.

The quality of natural habitat can be preserved with a sound food-plot strategy, even in the face of significantly higher deer numbers than once thought possible. As a result, fair chase (which can be compromised by the degradation of habitat and the resultant "taming" of deer in over-browsed habitat) can be protected if managers work to protect the environment. And protecting the habitat and ensuring fair chase are essential if we're to be seen as stewards of the resource by the hunting and non-hunting public.

If you want more and bigger deer on your hunting land this year and beyond, these numbers should convince you that the right food plots are well worth planting. Yes, you need high-quality native habitat, and in many cases, supplemental feeding of deer will prove to be quite effective as well. But as we've noted throughout this long-running series on private-land management, it's hard to beat the gains that come from mixing year-round food plots with the right deer-harvest strategy.