This variance stems from the dramatic physiological changes a deer goes through in a year. A buck's nutritional needs change as they grow antlers and then shed them, and gain and lose body condition from spring through winter. Does undergo changes in nutritional requirements as they move through the cycle of gestation, fawning, lactation and breeding.
In the next three issues of the Whitetail News, we will look at each season of the year and the specific nutritional needs of each. We will examine the determinants behind these nutritional needs and what you can do as a deer hunter and manager to help give your deer herd what they need to thrive.
VARYING SPRING CONDITIONS
The first thing to understand about spring is that it's a general time that can produce wide-ranging conditions. Even though the word “spring” pertains to March through June, conditions at the beginning of this period are typically far different than what they are three weeks into June. So when you analyze spring nutritional requirements, they will follow the same course and vary from early spring to late spring.
Spring conditions also vary depending on the region of the country. For the purposes of this article, we will look at spring from the vantage point of the middle of the country from North to South. Adding or subtracting a month or two will give you the conditions in your
region.
Early spring can be one of the most stressful periods in terms of nutrition. In many parts of the country, green-up has not yet occurred and might not for several weeks. Food sources such as waste agricultural crops, mast crops and browse have all but been exhausted from use through winter. This is the time when body conditions are at their worst. Liken a deer’s body condition in early spring to that of the energy reserves of a marathon runner in the last two miles of the race. The question is will body condition and the short food supply hold out until green-up occurs. Making problems worse are the dramatic swings in weather during early spring. March and April can bring 70-degree weather or produce tremendous snowfalls, or even worse, ice storms. Early spring is also typically wet and muddy, which when combined with the lingering cold temperatures of winter, will cause further stress to deer.
Mid to late spring begins a time of plenty in the deer world. Green-up is occurring, and both natural and planted food sources are beginning to produce fresh, highly nutritious food sources for deer. Intake normally increases during this phase of spring for deer to take advantage of these food sources and regain body weight lost in winter.
CHANGING NUTRITIONAL NEEDS
During winter, deer enter a semi-hibernation state, during which their metabolism slows, intake decreases and nutritional requirements are generally at the lowest for the year. However, when spring arrives, all of the aforementioned functions increase dramatically. The increased demands are caused by a need to regain weight lost during winter. Bucks commonly lose a high percentage of their body condition, dropping in body weight by as much as 25 percent or more. This body weight must be regained before most nutrients can be used for new antler growth. The most important nutrient to accomplish this is energy. Energy can come in many forms but is primarily derived from carbohydrates, fats and oils. At the same time, protein needs begin to increase as new antlers begin to form at the pedicles. Low levels of protein in a buck’s diet during early antler growth can negatively effect the overall growth of the antlers as compensatory gain is a not a characteristic of antler growth. Mineral and vitamin requirements for bucks begin somewhat low in early spring but increase rapidly in mid- to late spring as antler formation continues.
The nutritional requirements for does follow a similar pattern as the bucks but for different reasons. Although does might need energy to regain lost body weight, they also need energy for growing a fetus or two in the womb. During spring, does are in their final trimester of gestation, which accounts for nearly 60 percent of fetal growth. This rapid fetal growth requires high amounts of energy. Without this energy the fawns could be aborted or more possibly born at a low body weight, which is highly correlated to fawn mortality.
Protein requirements also increase because of fetal growth, as well as mineral and vitamin needs. In late spring, after the fawns are born, a doe’s nutritional requirements for all nutrients peak because of lactation. Doe milk is very nutrient dense — much more so than cow’s milk. Does require high amounts of nutrients to produce adequate quantities of milk to support their fawns as well as take care of their own bodily needs. Lowered milk production results in smaller yearling deer weights, which have been shown to correlate to lower maturity weights and decreased antler growth.
FINAL SPRING CHECKLIST
The key to nutritional management at any time of year is to understand the nutrients needed by your deer herd at that time and to identify which of these nutrients is not being supplied naturally. For example, energy and protein are needed in large quantities in early spring; but before green-up, these nutrients are in very short supply from natural food sources. It was this very thinking that led to the development of Cutting Edge Initiate, which is a full nutritional supplement designed for the pre-green up period of early spring. Initiate contains highly concentrated levels of energy and protein formulated to supplement the specific early-spring nutritional needs of bucks and does.
When green-up occurs, mineral and vitamin needs increase, and the need for supplemental energy decreases as mass quantities of carbohydrates can be found in new growth vegetation. At this time, Cutting Edge Optimize, Imperial 30-06 or Imperial 30-06 Plus Protein can be used to supplement the higher nutritional demands for minerals and vitamins.
Food-plot management is also critical for spring. Even though you cannot change the weather to make spring green-up hasten its pace, there are a few things you can do to produce faster growth and larger quantities of forage when green-up occurs. First, fertilizing your plots in the spring helps ensure faster growth and more new growth. Second, if you have not checked your soil pH in some time, get a soil test in early spring. You might find that you need to add more lime to your plot, which will help your plot be more productive and higher in nutritive value.
Finally, make sure that you have adequate amounts of perennials, such as Imperial Whitetail Clover, Alfa-Rack Plus, Chicory Plus, “Chic” Magnet and/or Extreme as part of your food plot plan. Perennials supply your deer with nutrient-rich vegetation immediately after green-up. Annuals, on the other hand, will take longer, since you will need to work the food plot, plant and then allow time for growth. This is not to say that you should not use annuals. Just make sure perennials remain a large part of the overall program if possible.
