In certain segments of the herd, such as fawns, yearlings and old bucks — who all have a higher energy needs — a certain amount of winter kill is likely. Although this scenario is hypothetical, you can certainly see how a habitat’s energy inventory is critical to the deer herd. Furthermore, we can also see how any change in variables can effect the energy supply. In the example, we talked about a poor mast crop, but we could also use lower than normal agricultural waste due to drought or a change in planting cycles; increased deer herd numbers on a property; extremely harsh winters, etc. Any change in these variables can have dramatic affects.

This is no different than an oil tanker leak, oil refinery explosion or any host of variables that affects fuel supply and, therefore, fuel prices. If you happen to live in the South, you might not be worried about winter. However, mid-to late summer can bring about similar energy deficiencies due to excessive heat and drought.

With all of this variability, it is vital that deer digest and utilize energy sources efficiently. The more efficient deer utilize dietary energy, the less energy supply variability will affect the deer herd. There are several practices you can do to manage energy supplies for efficiency and effectiveness. More on that later.

Energy Digestion in Whitetails

Energy is often referred to as a nutrient, but it is actually the derivative of other nutrients. The most predominant sources of energy in a deer’s diet are produced from carbohydrates and lipids (fats and oils). Because ruminants are very efficient in carbohydrate digestion and utilization, carbohydrates supply most of the energy in their diets.

Carbohydrates come in three basic forms: starch, sugar and fiber. Starches are found predominantly in seeds and/ or grains, with corn being the most recognizable. The starch in a seed or grain kernel comes from the interior portion (the seed germ).

Starch is found in nearly all seeds, hard mast and soft mast. Further, other plant components such as roots can contain starch.

Sugars can also be found in a variety of deer forages. The highest sugar contents are typically found in soft masts — wild cherries, apples, berries, etc.

Cellulose and hemi-cellulose are the two major forms of carbohydrates that are derived from fiber. In most deer diets, cellulose and hemi-cellulose are the most predominant dietary carbohydrate sources, as a deer’s diet is most commonly based on forage. Cellulose and hemi-cellulose are found within plant tissues and are broken down in the deer’s rumen by cellulolytic and

hemicellulolytic microorganisms.

Digestion of carbohydrates from starch, sugar and fiber (cellulose and hemi-cellulose) results in the production of volatile fatty acids. The predominant of these are propionic, butyric and acetic acids.

VFA production takes place in the rumen and is converted to glucose which, in turn, is used as an energy source. While all VFAs supply energy, they do not supply equal amounts of energy. Propionic acid produces roughly 28 percent more glucose than butyric, and 43 percent more than acetic acid. In terms of efficiency, the more propionic acid that can be produced from carbohydrates, the more energy will be supplied to the deer.

Lipids are the collective term for all fats and oils found in a deer’s diet. Although lipids are not as efficiently digested and used by deer as carbohydrates, they still play a substantial role in the dietary