Pursuing Quality Deer Management goals can be a year-round endeavor, but the importance of your management efforts are higher in spring and summer than perhaps any other time of year. Adults can lose 15 to 30 percent of their body weight during winter. This loss must be recovered quickly in time for a buck’s body and antler growth cycles to begin, and for a doe’s pregnancy and fawn-rearing needs. Let’s take a look at the protein and energy requirements of whitetails in summer, as well as how to meet these needs with high-quality spring and summer forages.
Spring Recovery and Summer Growth
Whitetails are well adapted to surviving winter – even harsh winters – however spring snow storms, floods or other events that restrict forage and delay green-up can be devastating. Bucks begin growing antlers in spring, but antler growth is secondary until body resources lost during winter are replenished. The amount needed to replenish the body depends on the severity of winter and the animal’s nutritional status entering it. The goal for some managers’ habitat efforts is to ensure bucks receive adequate nutrition to optimize antler growth. This is an understandable goal, but energetically speaking, antlers are less expensive than body growth for either sex and far less expensive than gestation or lactation for does. Whitetails have a relatively long gestation (about 200 days) and does have increased nutritional demands during spring. Although breeding occurs during autumn, over 80 percent of fetal growth and 90 percent of the energy spent on gestation occurs during the final trimester of pregnancy. For does bred in mid-November, the last trimester begins in late March/early April and generally corresponds to spring green-up.
Maximum antler growth occurs during summer and is directly linked to nutrition. Some bucks average over one inch of antler growth per day throughout the growing period (approximately 150 days), but can grow much more per day during the height of summer. Bucks with access to high-quality nutrition have the ability to express more of their antler growth potential while bucks on poor quality diets have restricted antler growth. This is common sense, but far too many hunters blame poor antler growth on genetics when the real culprit is lack of nutrition, lack of age, or both.
Fawns are born as spring turns to summer, and does now require even more energy as lactation is four to five times more costly than gestation and nearly 20 times more costly than antler growth.
A doe’s nutrient-rich milk contains twice the protein and energy per unit of volume as cow’s milk. Undernourished does still produce nutrient-rich milk but at reduced rates. Well-nourished does with twins generally produce 67 percent more milk than does with single fawns. Lactation is extremely expensive for does, and that is why they’re often the last to molt their summer coat and grow their winter coat; they’re putting energy into milk production so molting is delayed.
Fawns also have high energy demands. They weigh 5 to 10 pounds at birth, will double their weight within two weeks, and can triple it within a month. Fawns depend heavily on their mother’s milk for nutrition the first two to three months but can survive exclusively on vegetation by around two months of age. Fawns also have high protein requirements, especially at weaning when their diets should consist of 14 to 22 percent protein.
Creating a Diversity of Food Sources
Similar to energy requirements, protein requirements change seasonally, and they differ for bucks and does, and for fawns, young and mature deer. So, how can a manager best meet all of these requirements?
The forage lists that deer eat are extensive, and they vary regionally, locally and annually. For example, some preferred items are more available during wet springs, others during dry years. Some are more available during cool summers, others during warm years. The key to meeting the deer herd’s demands is diversity in your habitat management program.
It’s important to remember that a property’s potential for deer habitat is not fixed. In forested regions, forest management techniques can be used to increase high-quality deer forage. You want a diversity of forest types and age classes interspersed across the habitat. Clearcuts and seed-tree or shelterwood cuts create abundant food and cover at ground level. These cuts should be laid out in strips, checkerboards, or irregularly shaped patches to maximize edge. Fuelwood or small patch cuts also create high-quality habitat. These selection cuts should be by individual tree or 1 to 5 acres in size and scattered throughout your property. Brush piles created from slash provide shelter for deer and other wildlife and will protect new seedlings from being browsed. Managers can promote stump sprouts and enhance hardwood leaf production by conducting timber harvests or fuelwood cuts during winter. Browse production in these stands can be extensive, and it contains moderate energy and protein contents. The key is that it’s available continuously.
The importance of mast cannot be overstated. Many think of mast being most important during autumn as acorns and apples become available, but many soft mast species such as blackberry and raspberry are available during summer in early successional forest stands, and these are extremely important components of high-quality forage. Mast contains high energy and/or fats, but the drawback is sporadic availability.
“Old fields” are important, as they provide food and cover. Proper management of this cover type produces escape, bedding, thermal and fawning cover as well as abundant forbs for forage. Old fields can be maintained by prescribed fire, seasonal disking, rollerchopping, fertilizing, herbiciding, or a combination of techniques. Forbs have moderate to high energy and high protein, and most are preferred species. The drawback is they are limited to specific cover types.
Finally, your food plot program should supplement the native vegetation management. You should design your food plots to provide food as close to year-round as possible. A well planned program that includes a mix of cool-season perennials, warm-season annuals and cool-season annuals can provide forage for deer across all seasons. For the purpose of this article, spring and summer plots are the focus. Winter wheat in the North, annual clovers in the South, and cool-season perennials in both regions provide some of the earliest high-quality forage in spring. Warm-season annuals such as soybeans, cowpeas, and lablab can be used to provide high-quality forage during summer and even into autumn.
Be sure to focus on spring and summer nutrition so that bucks express their antler growth potential, fawns grow strong bodies, and does can feed those fawns. Spring and summer foods high in protein and energy are necessary to meet these nutritional demands, and they primarily include green leaves and buds of woody and herbaceous plants, soft and hard mast, forbs and legumes. Diversity is the key, and a mix of low-growing browse, soft mast, forbs and legumes are just what the doctor ordered.