Seasonal protein requirements of white-tailed deer
By Matt Ross, Whitetail Stewards, Inc
What is protein?
Protein is a general term that describes a large group of compounds that have a variety of different functions. The one thing that all proteins have in common is they are composed of amino acids. Amino acids are termed either non-essential or essential. Non-essential amino acids are produced in the body. Essential amino acids are derived directly from food deer eat. The majority of amino acids are essential, and therefore, must come from food.
Proteins are required in nearly every factor of life because they are important components of enzymes, hormones, antibodies, blood clotting factors, and cell walls. In order for these life components to function properly, deer require a regular supply of dietary protein.
Deer protein requirements
Protein requirements of deer vary by age, sex, physiological condition and season (Fig. 1). Pound for pound, fawns require more protein than adults because fawns are growing muscle tissue continuously throughout their first year of life. Because of their larger body size and faster growth, male fawns require a higher protein intake than female fawns. Muscle replacement and maintenance by adults requires protein, but proportionately less than that required by fawns. The protein requirement of yearlings slightly exceed that of adults. During late pregnancy and lactation, does require proportionately more protein than bucks.
Seasonal protein availability
The time of year a forage becomes nutritious and palatable determines how important it will be to deer, and how much protein it will provide. For example:
Forages that are most nutritious and palatable in the SPRING are important for:
helping all deer recover from winter stress
providing pregnant does with nutrition needed to support developing fetuses through the third trimester and to begin producing milk
providing bucks with nutrients needed to begin growing antlers
Forages that are most nutritious and palatable in the SUMMER are important for:
providing does with nutrients needed for producing milk
providing nutrients needed by growing fawns
supporting further antler development in bucks
Forages that are most nutritious and palatable in the FALL/WINTER are important for:
providing nutrition for weaned fawns that are still growing
providing energy deer need to prepare for winter
replacing energy lost during the rut
Because protein requirements must be met concurrently with energy requirements, protein consumption must increase as energy demands increase. Most food plot forages offer food sources high in protein but low in energy. Acorns and many commercial grains, such as corn or wheat, have relatively low levels of protein, but high levels of energy (fat). Woody browse items are typically low in both protein and energy content (Fig. 2). In general, plant protein is highest in early growth stages. For example, protein in young grasses, forbs and browses can be as much as 15-25% higher than the same plants at maturity.
How much protein is enough?
Deer nutritionists generally agree that a diet containing 16-20% crude protein is more than adequate to support deer protein requirements. Human nature leads us to believe that more is better than less. However, this is not the case when it comes to protein consumption by deer. After deer meet their minimal protein requirements any additional protein consumed does not lead to larger antlers or bigger bodies. It can, however, equate to higher costs to the hunter and deer manager who is feeding or improving habitat for deer. Thus, to reduce costs and efficiently meet the requirements of all age classes of deer it is best to purchase and provide forage with a minimum of 16% crude protein. Investing in forage that provides much greater than 20% protein will not vastly improve the herds' health and should probably be considered a waste of money.
