Just what is deer nutrition? Is it which kinds of acorns a deer prefers? Is it how many pounds of forage a deer consumes in 1 day? Is it whether we should supplement our deer with a feed ration? Actually, nutrition is none of those things and all of those things. Nutrition is the study of how animals turn their food into living body tissue. Nutritionists are really not as much interested in what a deer eats as what nutrients are in that food.
The nutrients of concern are water, protein, carbohydrates (starch, sugar, and fiber), lipids (fat and oil), minerals, vitamins, and of course, energy. In order to ensure that a deer herd has an adequate diet, we need to know the nutrient requirements of deer, how much food is available, and the nutrient content of that food.
Unfortunately, nutrition is not an exact science. Probably no other species of wildlife have been studied as much as the white-tailed deer, and yet we still do not know enough about their nutrient requirements. We do know that their requirements vary depending on whether they are male or female, whether they are fawns, yearlings, or adults, whether they are growing, the season (environmental factors such as extreme heat or cold), and their physiological state (such as pregnancy, lactation, or antler growth).
Complicating matters further are the facts that food availability, by species and amount, changes seasonally, the nutrient content of foods varies by season, and the deer themselves vary their intake over the year. Matching up all of these factors can be difficult and frustrating to the nutritionist, but it is also fascinating work. The following information will briefly review the nutrients required by deer and some of the factors affecting those requirements.