Spring is officially here and plants are green again, but the lack of rainfall has kept native vegetation from really taking off. On the bright side, trees, shrubs, and vines are leafing out thanks to some precipitation and warmer temperatures, and providing new-growth browse for hungry white-tailed deer. And speaking of deer food, there is some on-going research that may shed more light on the supplemental feeding of deer and its impact on native plants. Deer managers agree that supplemental feeding, whether it be protein pellets, whole cotton seed, or some other type of high-protein food, really helps local deer populations.

However, the words “supplemental feeding” have become almost synonymous with “deer management” in some circles, and although not totally accurate, it’s not far off. Although the management of deer populations incorporates much more than the addition of free-choice protein, most landowners giving deer management an honest effort are providing some sort of supplemental food. So as common as this practice is for the management of white-tailed deer, it also deserves further attention. By definition supplemental food is, well, supplemental. The foods placed out for deer are merely there to add to an individual deer’s natural diet, not replace it. If this were false then a property could support an unlimited number of deer as long as food was continually added to the system. This won’t work. 

But some often confuse deer breeders and deer management. Yes, deer can live in pens devoid of vegetation with protein pellets and water, but imagining a ranch that looks like a deer pen would be a sad, sad sight and the deer population would still suffer from density-dependent factors. It was commonly thought that the addition of supplemental food reduced a deer’s use of natural plants — and it’s true — but maybe it all goes down a little different. Past research found that deer provided with supplemental food in the form of free-choice protein pellets still used native plants, but the deer only consumed the most highly preferred plants available to them.

However, preliminary results from research conducted in South Texas suggests that supplemental food does not encourage selective foraging by deer. So why is it important? Well, we all know that deer prefer to browse on certain plant species. Food preference is probably a function of palatability, digestibility, and overall nutritive value. In areas with high numbers of deer, highly palatable browse species become over-utilized, stunted (hedged), fail to reproduce, and can die. When this happens over a ranch or ranches and year after year, entire plant species can disappear. This leads to an unhealthy system with plant species after species succumbing to over-use over time.

Under the first scenario, supplemental feeding would not prevent the over-use of preferred browse species by deer, but new research may find that free-choice feeds reduce the use of preferred browse. This is important for deer managers that are interested in providing good wildlife habitat because it gives real credit to the fact that free-choice pellets really are supplemental. Deer not only use preferred browse species, but they also use moderately and slightly preferred browse plants. This widespread use of browse species suggest that supplements can buffer the use of native plants by deer, but not fully protect them.

So regardless of what the current study finds, both scenarios end up proving that deer can not live on supplemental feed alone. Even when supplemental food is provided free-choice, white-tailed deer still desire native browse plants in their diets. Not only are these plants important for food, but also for the shelter and screening cover they provide for deer and other wildlife species. And let’s not forget that browse plants typically contain protein levels ranging from 15 to 35%. And that can feed your deer and really supplement your supplement, for a lot less money.

An important component of any deer management program is ensuring the physical health of individual white-tailed deer, as well as the overall deer herd. Individual deer health is important for maintaining body mass, promoting maximum antler growth in bucks, and optimal milk production in does. Because the energy and protein requirements of deer have become more understood over the years, deer managers now focus much of their attention on meeting and even exceeding the food requirements of white-tailed deer. This can be done in either of two ways, either from native habitat or through supplemental food.        

Although protein pellets ranging from 16 to 20% protein are often offered in free-choice feeders, people often consider other sources of protein for diet supplementation. Several sources of “alternative” protein include crop seeds such as soybeans and whole cottonseed. However, cottonseed contains a compound known as gossypol, a toxic pigment the plant naturally produces and is believed to discourage consumption by animals. Gossypol can reduce reproductive ability in some mammals when consumed at high rates. Fortunately, recent research in Texas has found that white-tailed deer are not negatively effected by whole cottonseed, even when it makes up a high percentage of a deer’s diet.

LSONEWS: “We’ve done a series of independent projects,” said David Hewitt, the institute’s Stuart W. Stedman Chair for White-tailed Deer research. “We had five bucks on a 40-percent whole cottonseed diet and five bucks on pellets and chopped alfalfa from June through September. We looked at body weight, semen samples, and blood. We did not see any negative effects the first year.

The bucks on 40-percent whole cottonseed did lose some weight while the other bucks (on pellets and alfalfa) did not. Again, there were no toxic effects on the sperm or red blood cells. The bucks maintained their weight while the control group bucks gained weight. The doe weights did not change.”

And at over 22% percent crude protein, cottonseed really is a high-protein food alternative that is also rich in phosphorus, one of the most limited nutrients in native forages. And in addition to deer performing well on it, there are some other positives surrounding the feeding of whole cottonseed. Non-target species, such as feral hogs, raccoons, and other varmints do not eat cottonseed. This can help your bottom line by limiting consumption by animals other than deer.

Cottonseed is a solid choice as a supplement for whitetail because it’s high in protein and does not easily degrade in moist conditions. In fact, you can simply place it out on the ground or in a free-choice feeder. EasiFlo cottonseed has the same nutritional benefits as regular (fuzzy) whole cottonseed, but is starch-coated to improve handling. This new cottonseed flows freely and can easily be augered through traditional grain-handling equipment. Whole cottonseed as a supplemental food for deer can increase growth rates, improve fawn production, and increase antler development in bucks, but it is not a complete ration.

Whole cottonseed does lack many of the micro- and macro-nutrients that protein pellets contain. And although cottonseed has many great qualities, its availability may be limited in your area. So remember, regardless of whether you decide to supplement a deer herd through protein pellets, crop seeds, or food plots, supplements are only intended to compliment native forage, particularly during periods of stress.     

When it comes to white-tailed deer management we do know a lot, but we do not know it all. There is a lot that is not known about how white-tailed deer affect their habitat under different densities with and without supplemental feed, however, that is exactly what a research project initiated on two South Texas ranchesd hoped to determine — the effects of deer on native vegetation.

To accurately conduct the research, six 200-acre enclosures were constructed on both ranches. In addition, they were divided into 3 pairs — each with target populations of 10, 25, or 40 white-tailed deer. One of each pair was supplemented with a free-choice (all you can eat) pelleted supplemental ration and the other was left to forage from only native forbs and browse. To document changes in habitat condition, canopy cover and biomass were estimated annually.  

Forbs consumed by deer declined where feed was not provided, but they increased when feed was available. The supplementally fed pens with the lowest deer density had the greatest decrease in forb use. However, even under various densities and some pens not receiving any supplemental feed, the pens did not show any significant a difference in plant utilization. 

From the study, the researches concluded that free-choice supplemental feeding appears to alleviate foraging pressure, however, results should be considered preliminary because extreme annual variation in rainfall may have different outcomes. The results of the study were somewhat complicated because although the researchers could control many factors, they could not ensure that all pens were exactly the same with regard to vegetation. In addition, had the research taken place during drought years, the results could have been much different.

It makes sense that higher deer densities would have greater impacts on native plants, especially in areas where deer do not receive supplemental feed. However, this study did not come to that conclusion and it probably had something to do with outstanding natural habitat conditions during the study period.  Had the study followed the individual herds for a longer period of time, or had habitat conditions been poor to very bad, then the low density deer pens would have faired best, especially those with supplemental feed. 

Many landowners and hunters consider supplemental feeding an important factor in deer management and a source of nutrition when native forage is inadequate either in quantity or quality. Under certain conditions a supplemental feeding program can help. However, most deer feeding programs which provide sufficient additional nutrients to be of value are quite expensive.

There is a distinct difference between feeding and baiting white-tailed deer. Maintaining deer feeders from October through December is a common practice on many ranches to attract deer to hunting blinds during the hunting season. Unfortunately most of these baiting efforts cease just before additional feed is really needed by the deer — in late winter. Supplemental feeding is most-beneficial during stress periods. Stress periods for deer are usually encountered when the protein content of the forage is at a low level during severe winters, dry springs and dry summers.

As mentioned, supplemental feeding of deer is expensive, and unless properly done it may be of little or no benefit to the deer. The most efficient means of insuring adequate nutrition is through a good range management program that provides sufficient cover and a variety of browse plants as well as forbs. This is done by reducing deer numbers and domestic livestock numbers to levels that allow the range to recover and remain in good condition.

A common mistake made by many landowners attempting to develop a range management plan is to disregard the number of animal units of deer present when calculating use of the range. If deer are present, they will also be using available forage and must be considered as part of the stocking rate. If large numbers of deer are desired, domestic livestock must be reduced to prevent damage to the range.

Under good range conditions, deer and cattle do not compete for food. However, deer, sheep and goats are in direct competition for the available food supply. When a range is in poor condition deer and cattle will compete for forb and browse plants.

Supplemental feeding of deer may be beneficial if the herd is harvested adequately each year and the range is in good condition. Only under closely controlled conditions will supplemental feeding benefit growth-rate of body and antlers. The benefits of a supplemental feeding program may be more quickly realized when feeding is done within game-fenced areas that allow the landowner to closely control the white-tailed deer population.

White-tailed deer habitat consists or food, water, shelter, and also space. Thus, food plots and supplemental feeding only impact the nutritional carrying capacity of a particular piece of property, not the total or actual carrying capacity. Assuming there are both adequate water and cover, supplemental feeding can greatly increase the number of the local deer population. Supplemental feeding has become commonplace in deer management programs across the country, but is it healthy?

One thing to keep in mind is the amount of space and and habitat per deer decreases as the population size increases! More deer in an area means less area for each individual deer. This may not be a problem if the number of deer is below the carrying capacity of the area, but this rarely seems to be the case with white-tailed deer.

One of the arguments used by those in support of supplemental feeding is that it not only enhances the nutrition and resulting health of the deer, but that it could possibly take pressure off of the natural vegetation by decreasing deer browsing. Unfortunately, there is little data to support this and plenty of data to refute it.

The use of food plots, supplemental feeding, and baiting has been greatly debated throughout the U.S., but should this extra nutrition really be included as part of the carrying capacity estimates for your property? The research says no.

Studies in Texas have show that fed deer can degrade habitat by over-consuming high-quality browse and under-consuming low-quality plants. Other data found increased browse pressure within a 1-mile radius of feeders, which can only be attributed to the concentration of deer!

This research does, however, have a silver lining for hunters. Several studies have found that the home range of a deer becomes smaller when feeders are present. One research project even found that home range sizes of fed deer were 50% of that of unfed deer. But that good news does not come without a price. Browse pressure near the feeders was 7 times that of habitat occupied by unfed deer.

In addition to degrading habitat adjacent feeders, supplemental feeding has been suspected of contributing to the spread of certain diseases within various species of North American ungulates, such as tuberculosis in deer, chronic wasting disease in elk and deer, and brucellosis in elk and bison.

So what does all this mean? Well, if you wish to provide supplemental feed — make sure that it is in fact supplemental. Avoid using the addition of food resources as justification to artificially inflate deer numbers on a property and subsequently degrade habitat. In addition, make sure you understand that feeders do concentrate deer (even if individual deer use the feed site at different times) and does make them more prone to disease.