WINTER NUTRITION GAPS

By Bill Winke

         This past summer, a small group of landowners in my part of Iowa hired a high-profile consulting biologist to offer advice on the best strategy for managing whitetails on their properties. They invited me to the meeting. It was a great opportunity to learn and ask questions in a real case-study setting.

         One of the problems with the properties was a lack of winter food. The farms commonly ran out of desirable food sources in December, leaving only substandard groceries for deer until spring green-up in early April.

         During January, February and March, the farms — which encompass a large area — are void of high-quality food. The obvious question arose: “How much effect does this three-month gap in nutrition have on the quality of the antlers the bucks grow each year?”

         The biologist said antlers actually grow from calcium and phosphorous stored in the skeleton. It takes a lot of energy out of a buck to produce antlers. If that buck is not healthy, it must first rebuild its body from the rigors of winter before it can put maximum energy into antler growth. In other words, the health and maintenance of the animal take priority over antler growth.

         That’s when things got interesting. The biologist said that if a buck misses those three months of high-quality nutrition, his maximum antler size might be 20 percent to 25 percent smaller. In other words, a 150-class buck might have been a 180-class buck had he received better nutrition through life.

         I don’t know if the biologist got everyone else’s attention, but he certainly got mine. When you are sitting in a tree stand and a buck is walking toward you, there is a big difference between a 150 and a 180-class buck. The shock value of those 30 additional inches is tangible. I love it. So maybe if you supply a high-quality diet for a buck’s entire life, it's conceivable that his antlers will be 20 percent to 25 percent larger than if he eats only low-quality foods during those months. There's no doubt that healthy bucks tend to produce more sticker points, and sticker points add up fast.

         In the end, a 150-class buck with poor winter nutrition could well have been a 180-plus-inch buck if he had a consistently superior diet.

         If that's true, deer hunters focused on producing quality bucks need to take winter nutrition gaps very seriously. Especially the further north you are. More to the point, we need to plug those gaps as quickly and as effectively as possible.

Some Misconceptions about Winter Feed

         I used to hunt a property where one member of the hunting party always disagreed with our budget to plant food plots. Every year he would say, “That’s a huge waste of money. These deer have a lot of fat in them when we field-dress them each fall. There is no way they are going to starve during winter. We just don’t have deer starving in this state. There is always plenty of brome grass for them to eat.”

         Wow, I could write a book about all the problems in that last paragraph. And you can imagine the handfuls of hair I pulled out when I had to butt heads with this guy at our annual meetings. It was colorful, to be sure. It's also one of the main reasons I’m an ex-member of that hunting group.

         I’ll start with the first point, about body fat. Yes, deer often have a lot of body fat going into winter, but the does are generally the butterballs, not the bucks. It's common for a buck to run off most or all of his body fat during the rut, leaving him with little in reserve.

         More often than not, he goes into the winter in poor physical condition. If it is a difficult winter, or if food is in short supply, the stress will be a real problem. Winter-kill among mature bucks after a hard rut is common. Those that don’t die are certainly at a disadvantage.

         During good conditions, a buck can still recover and regain enough stamina to carry him through the tough months ahead. However, if conditions are adverse, he will experience a setback in body condition. A buck-to-doe ratio skewed heavily toward does also makes the situation worse. In that case, the bucks rut longer each year. A prolonged rut uses up more of the buck’s precious energy, leaving him more vulnerable and less likely to grow his best possible antlers the next year.

         I have spoken with several deer managers who have breeding programs about this effect. If they leave a buck with lots of does, he will grow a smaller rack the next year. However, if they put him with a small number of does or keep him from breeding, his rack size doesn’t diminish — and that’s in a setting without food-related stress. Imagine how much worse it will get if that buck has to scrounge for food after two months of chasing does.

         “I like to explain antler growth using an analogy,” said Matt Harper, Whitetail Institute’s deer nutrition specialist. “Think of a cup that you are filling with water. When you fill the cup, you are rebuilding the buck’s physical needs. It's only when the water runs over the top that the buck focuses available resources on growing antlers. The fuller the cup is at the end of the winter, the sooner it will overflow in spring. The buck’s body can devote more of his daily energy and food intake to growing antlers rather than upgrading body maintenance.”

         Let’s go back to my friend’s second erroneous point. If you are trying to grow quality deer, including bucks that reach their antler-growth potential, the critical standard is not simply preventing starvation. The critical standard, using Harper’s analogy, is to produce bucks that have as full of a cup as possible when spring green-up arrives. Anything less is a compromise.

         The final point revolves around the mistaken concept that deer can do just fine on the brome grass in most Conservation Reserve Program fields. I ran that one past a few biologists, and they just laughed. Brome grass is a diet deer resort to when holding starvation at bay. It's not a food source that will bring bucks through the winter in optimum condition. The cup will be far from full after a winter eating brome grass.

         It should be clear that winter nutrition gaps are bad for your deer and will directly affect the antler-growing potential of bucks. Now, let's focus on how to plug those gaps.

Plugging the Winter Nutrition Gaps

         “Deer don’t really need near as much protein or minerals during winter as they do during summer,” Harper said. “Their needs change with the season. What they really need during winter is energy. That comes from carbohydrates and fats. Our solution to this need is Cutting Edge Sustain. We never intended that this product would replace the five pounds of food that a deer generally eats in a day, but it does provide a serving size of four to eight ounces per head. It is a supplement; think of it as an energy bar rather than a full meal.

         “However, the Cutting Edge products fill a very specific need during the winter: the need for increased energy to stay warm and ward off the rigors of the rut. The product is granular. You can offer it in a bunk or pour it straight on the ground.”

         Imperial Winter-Greens is another Whitetail Institute product that works well during late fall and winter. It stays green and lush well after other forage plants go dormant. In that way, it remains a viable food source when many things in the whitetail’s world have shriveled and dried to brown stalks.

         I grew Winter-Greens this past year in an Iowa food plot. Actually, I put the seed through a tough test. I had a soybean plot that didn’t materialize because the extreme drought we suffered for much of Summer 2006. In early September, there was a good rain in the forecast, so I hand-broadcast Winter-Greens onto my soybean plot. I checked the plot often, and soon it was a lush green carpet of brassicas. I’m sure the agronomists on the Whitetail Institute staff are cringing right now, because broadcasting onto untilled ground is not a recommended method for planting this seed. However, it grew well — at least in this case.

         More important, deer loved them and benefited from them. The two-acre plot was in the middle of an alfalfa field, yet deer went out of their way to find and eat the Winter-Greens late that fall. They were hitting it hard even before the alfalfa withered.

The Most Critical Time

         “The last six weeks before spring green-up is the time of greatest stress for whitetails,” Harper said. “By then, much of the native forage and food plots have been eaten, but the new growth of spring has not yet begun to materialize. This also gets you into the third trimester of fawn development — a time when two-thirds of total growth occurs.

         “If the doe suffers from stress at this time, it affects the health of the unborn fawn. This means the fawn will get off to a slower start. The health of the doe at the time of birthing also affects the amount of milk she produces and that will also affect the health of the fawn.

         Deer can’t recoup lost body condition if the stress lasts for a prolonged period. For example, if a buck has low quality nutrition for its first three years, it will not suddenly produce a larger skeleton if it receives better nutrition at age four. In other words, the maximum size of the antlers a buck produces when he is four or five years old are not just the product of the prior year’s nutrition but rather the product of his lifetime of nutrition. That's why it is particularly important to get fawns off on the right foot and keep them in fine shape through adulthood.

A Practical Hunter’s View of Winter Food Plots

         Food plots are always important to the health of deer, but they aren’t always the best places to shoot a nice buck. In fact, during the peak of the rut, does will sometimes avoid food plots because bucks constantly harass them there. Instead, they may hide out and lay low until the rut passes, and then they emerge in full force. Bucks might still stop by a food plot during the rut to look for does, but they don’t use these areas as heavily at that time.

         On the other hand, food plots are awesome places to shoot deer — including big bucks — during the late season. I'm always excited for the arrival of cold late-season hunting in December and January. I know deer will be piling into my winter food sources, and will be more predictable and vulnerable at that time than any other time of the season, including the rut.

         If deer aren’t hunted hard during the early portions of the season, the late season is often the best time to shoot a trophy. But you can only shoot that trophy if you have food sources deer desire. Go ahead and throw out all the biology and good reasons for supplying ample winter food that Harper has suggested. There's a more compelling reason to pile on the winter groceries. From a selfish standpoint, these locations offer exceptional hunting.

Conclusion

         High-quality year-round food sources are very important. Deer need this resource to reach their potential for body weight and antler development. Of the four seasons, especially the further north you are, winter offers the most challenge and stress for most deer. Many deer managers fail to provide adequate food at this time. Make a plan that includes plenty of highly nutritious, energy-rich foods in January, February and March, and you will be rewarded with larger bucks each fall.