SUPPLEMENTAL FEEDING OF WHITE-TAILED DEER WITH SOYBEANS
Dr. Keith Causey
School of Forestry & Wildlife Sciences
Auburn University, AL 36849-5418
Interest in quality white-tailed deer management seems to be greater than ever. State wildlife agency sponsored programs designed to assist hunters and landowners in this endeavor have sprung up throughout the South and other regions of the U.S. These programs primarily make it possible for participating clubs and landowners to harvest antlerless deer throughout the hunting season to achieve adequate control of deer numbers on property leased or owned. While population control ultimately is critical to quality deer management, population control, in and of itself, does not necessarily result in physical improvement of the remaining deer in many areas of the U.S., especially the Southeast.
Studies from Florida, Georgia, South Carolina, Alabama and elsewhere are providing data indicating that, after many years of intensive population reduction, there has been no significant improvement in body and/or antler size by sex and age-class of the deer populations under study. It appears that food quality for the remaining deer often is no better than before population reductions occurred and, without nutritional improvement to go along with population management, we simply wind up with fewer deer of the same physical dimensions as before. Using a humorous story to illustrate this point, let=s assume that a population of humans, feeding primarily on lettuce, was not looking very thrifty. A decision was made to move half the population and thereby provide twice as much lettuce to the remaining individuals. I think the results would be obvious. Food quality not quantity obviously is a major limiting factor here and having access to all the nutritionally inadequate food one would care to eat does not result in significant physical improvements. Neither does simple population reduction, in the case of many southern white-tailed deer, result in habitat improvement.
The high quality food plants that produced big-bodied and big-antlered deer in Alabama 30 years ago apparently are greatly reduced or even eliminated from decades of abusive browsing and grazing by deer. Most native forages, although often quite plentiful in southern habitats, furnish less than half the protein and energy reportedly needed for maximum body and antler growth by white-tailed deer on a year-round basis. Population reduction cannot remove this major impediment to quality white-tailed deer management. One can only speculate how many years would be required for these habitats to recover to their former quality even if deer were totally removed from the area. Native grasslands that were overgrazed by cattle in the 1800's have not recovered from this abuse in over 100 years and it appears that millions of acres never will. The native high-quality plants have been replaced by exotic plants and low quality native plants.
There are numerous ways to improve the overall nutritional plane of free-ranging deer including cultivation of year-round food plots containing high energy forages, fertilization of natural forages, ad libitum access to range pellets and/or ad libitum access to high energy seeds or grains. All the above options can become too expensive, impractical, or both, depending upon whether we truly are trying to improve the overall nutritional plane of a deer herd or simply trying to attract them to a particular spot for viewing, harvesting, etc. Deer baiting and deer feeding are two entirely different endeavors although often it is difficult to clearly distinguish between them. My idea of supplemental feeding is a conscientious effort to improve the overall nutritional plane of deer on a seasonal or year-round basis, preferably year-round. There hardly is a time in the annual life cycle of deer when one or another age or sex-class in the population is not in need of high-energy, high-protein food. Gestating females, lactating females, weanlings, yearlings, post-rut mates, etc. all have special and different needs. Therefore I believe anyone wishing to overcome nutritional deficiencies in many southern deer herds should supplement year-round. Of course in some southern states, Alabama included, it is illegal to do so during hunting season if hunting is allowed. The legality of feeding any wildlife should always be investigated before implementing such programs when hunting also is involved.
Free-ranging deer and even many enclosed populations make up the bulk of their diet with natural forage. The nutritional content of these natural forages serves as an indicator of what kind of supplemental feed one should make available. Generally speaking, deer of all age and sex classes, on average, need about 17 percent crude protein year-round in their diet in order to fully express their genetic potential for body or antler growth. Some age and sex classes require more, some less. Of course digestible energy also is very important but protein content and energy often are closely related.
Now consider that may forages produced on southern soils contain about half the minimum protein and energy needed by deer for maximum growth. Only in spring and early summer do researchers find native forages with crude protein contents meeting minimum needs. Since, in most instances, deer with access to supplemental feed, will still eat mostly natural forage, the ideal supplement will be one quite high in protein and energy. If we desire to bring a diet averaging 8+ percent protein up to 17+ percent, we need a concentrated supplement. For example, deer generally consume 3-4 pounds of forage (air-dried wt) per 100 lb of body weight/day. If this forage averages + 8 percent protein one could never boost it to +17 percent with a supplemental food containing less than 20 percent protein unless the supplement replaces the natural forage entirely. On the other hand if the supplemental food were a high energy product with 30-40 percent crude protein, about 3/4 lb of this supplement per day per deer per 100 lb would result in the overall crude protein level of the natural forage plus the supplement being about 17+ percent. In my opinion this should be the function of a diet supplement. It should not be a substitute for natural forage
At our deer research facility, we have begun experimenting with supplemental feeding of raw soybeans. Deer take to them very well both in the pen and in free-ranging situations. Whole soybeans range in crude protein content from 30-40% depending upon the particular variety. Soybeans contain 18-20% fat and are high in digestible energy. Because they are so rich, deer tend to consume limited quantities on a day to day basis. Currently our yearling deer weigh, on average, about 100 lb and are consuming about 1 lb of soybeans per day to go along with about 2 lb of low protein (8%) pellets. Both are offered free-choice. In another pen under the same conditions our yearlings are eating 2 lb of shelled corn per day along with 1 lb of the low protein pellets. Of course corn is only about 8% crude protein and 2-3% fat but high in energy. We will evaluate the body and antler growth of these two study groups when they reach 18 months of age. We also will be evaluating digestibility and utilization of soybean, corn and low protein pellets.
I am aware of several situations in areas of Alabama with poor deer habitat related to soil conditions. One area is a 3000 + acre enclosed deer herd and the others tracts are of similar acreage but the deer are free-ranging. These sites have covered trough feeders about every 100 acres. Landowners report an average consumption of about 2500 lbs of soybeans per week and the areas have experienced impressive improvement in antler quality.
To truly supplement a deer herd of any size with soybeans or high protein feed is an expensive and labor intensive endeavor but so is any attempt to do the same by any other means including agronomic crops and/or fertilization of native forages. However, if soybeans prove as effective as they appear to date, they may very well be the best and most cost effective means of deer herd diet supplementation in many situations.
School of Forestry & Wildlife Sciences Extension
602 Duncan Drive · Auburn University, Alabama 36849