Understanding Protein and How It Fits In Your Management Plan

By Matt Harper

 Frequently, when someone receives a small piece of knowledge, it makes them a semi-authority on the subject. No doubt, the information age we live in has proliferated and expanded this condition. Often, the information you receive is inaccurate, but if you read it online or via old fashioned print, it has to be gospel, right? Even if what you have read or been told is true, it might be only a small piece of a much bigger picture and might contribute to using the information incorrectly. 

Case in point. About three years ago, I took my youngest daughter to watch a high school football game. By the time the third quarter ended, our high school team was getting slaughtered. A couple of ladies behind us had been yelling advice most of the game, and because it was the third quarter and the team was behind by three touchdowns, the advice was growing to a crescendo. During one play, the quarterback dropped back to pass, scrambled and ended up tucking the ball and taking a sack. “You got to get rid of that ball,” and, “Throw the darn thing,” were the comments tossed at the young quarterback. Those statements could have hit on the right idea, but not when there was no one open and throwing the ball would have probably ended up in an interception. I know that because I played quarterback in high school. I had tried both options and threw my fair share of picks. I turned to my daughter and said loud enough for several rows of folks to hear me, “You know what sweetie, I have always felt that if you have never experienced first-hand what you are giving advice on, your advice counts for squat. I mean, I have never given birth, so I would not give an opinion on how to deal with a contraction.” My daughter looked at me like I was insane, but I didn’t hear any more comments from behind me the rest of the game. The whitetail world has no shortage of information on any number of topics. TV, magazines, blogs, websites, trade shows — you name it, and there are plenty of places to give and receive deer knowledge. For the most part, it is good information that, when applied correctly and under the right circumstances, will produce good outcomes. Bad results are a derivative of improper application or not realizing how this information fits into a bigger picture. For example, I heard a guy on TV say you should follow up a deer right away after a shot because the coyote population was increasing so much that the dogs would scavenge your future deer steaks before you get to it. Well, if you know you have a great hit and have a lot of coyotes in the area, maybe that's true. However, if your shot was so-so, I would suggest waiting even if you have coyotes in the area. Jumping a wounded deer that has not yet expired will most likely leave you with nothing to take home. I have also heard people say that a particular food plot variety is the absolute best on the market. Even if it is “the best,” there are other factors to consider. Imperial Whitetail Clover is the best food plot product on the market, but if you try and plant it in a sandy, low pH soil, you will not get the results you are looking for. But without doubt, one of the most used but least understood terms in the deer nutrition world is protein. Protein has become the magic nutrient that is to deer nutrition what Kleenex is to facial tissue. If there is a conversation about deer nutrition, protein will certainly lead off the chat. But what do you really know about protein? What is it, why is it important and how does it fit into your management program?

What is Protein?

Protein is defined as naturally occurring complex combinations of amino acids that contain carbon, hydrogen, oxygen and nitrogen. Most protein values you see or hear about are given as crude protein. Crude protein is the total protein value of a plant or supplement. However, protein can be further broken down into amino acids such as lysine, methionine, threonine, leucine, cystine, arginine and so on. Each one of these amino acids has a specific function, and the configuration of these amino acids varies between food sources. In other words, two food sources might have the same crude protein value, but one might have more lysine than the other. The importance of amino acid profiles in feed stuffs has been studied far more in mono-gastric animals such as pigs and chickens than it has in ruminant animals. Most swine and poultry diets are not formulated based on crude protein but rather are balanced based on specific amino acid levels. Ruminants have the ability, because of rumen microbial populations, to produce a protein in the rumen called microbial protein. Of course, to produce this protein, the rumen microbes feed off of the food ingested by the animal. Highly digestible protein feed stuffs are needed by the microbial population to produce high levels of microbial protein. In fact, digestible protein, or DP, is a commonly used value when formulating ruminant diets. In simple terms, DP is the value of protein used by the animal when measuring the amount of protein ingested versus the amount of protein found in the feces. Ruminants also have the ability to convert nonprotein nitrogen, or NPN, into microbial protein via the rumen microbial population. Although NPN is not true protein, the nitrogen component is used by the microbial population to produce protein. In addition to microbial protein, certain protein sources will not be broken down by the microbial population and will exit the rumen intact. These proteins are called bypass proteins, as they bypass degradation in the rumen. Bypass protein can then be used and digested further down the digestive system. Although microbial protein is typically sufficient for average growth and maintenance, high-producing ruminants can benefit from bypass protein. For example, a high-producing dairy cow will often be fed a certain percentage of bypass protein because the microbial population might not be able to produce enough protein to sustain the higher level of production.

What Does Protein Do?

Protein has many functions, but chiefly it is the building block of the muscle and bone. Protein is also found in many other organs and is a major component of blood. Essentially, protein is needed to grow and produce things, with muscle and bone being two principle structures. However, protein is also vital for lactation/milk production, as the mammary system will not produce maximum amounts of milk without enough protein in the diet. Aside from growth, protein is also needed for body maintenance. For example, weightlifters increase muscle mass by first breaking muscle down (via weightlifting) and then let the body build the muscle back up to a larger size. A crucial part of this regimen is the consumption of large amounts of protein to supply the body what it needs to rebuild the muscle. In terms of bone growth, large amounts of protein are required during the growth and development of the skeletal system. In fact, young growing bone is composed primarily of protein. Protein in a deer’s diet will contribute to all the aforementioned functions, including muscle growth, bone growth and lactation. As with all young, growing animals, protein plays a major part in a fawn’s diet. Fawns are growing muscle and bone, both of which require large amounts of protein. Fawns require as much as 26 percent or more in the diet the first few months of their lives. Most of this protein early in life is found in the milk supplied by the doe. Thus, does require a great deal of protein to produce this protein-rich food supply to their fawns. A doe’s protein requirements are considered to be around 18 percent during lactation. If protein is limited in the doe’s diet, she will produce less milk, and therefore the young fawn(s) will receive less protein for growth. It is important to note that malnourished fawns have less chance of surviving, and those that survive might be stunted the rest of their life. Protein’s role in a buck’s diet is probably the most unique within the deer herd. Antlers are grown and shed each year, and because antlers are basically growing bone that is outside of the body, a high protein level is needed in the diet to maximize this growth. A velvet antler is approximately 80 percent protein in the early growth stages and a hardened antler is 45 percent protein. Further, when you consider that protein is needed for other functions in the body, such as maintenance, and that these functions take precedence over antler growth, it becomes apparent that a lack of protein in the diet will likely result in stunted antler growth.

Putting this Knowledge to Use

So with that being said, how do you use the things we have discussed or derive any relevance from it? First, I think it is valuable to gain knowledge and understanding of a topic even if not all of it is applicable. You might not study the amino acid profile of a particular food plot forage, but knowing that there is more to protein than just the crude protein value could be beneficial. For example, when you look at a protein value, you might ask yourself what the protein digestibility is. That might be difficult to ascertain, but on a practical level, if a food plot forage is highly digestible, the protein in that food plot forage is more than likely highly digestible. So if the goal is to get protein to the deer herd, look at the characteristics of the forage. Heavy-leafed, thin-stemmed forages like those in Imperial Whitetail Clover and Alfa- Rack Plus tend to be highly digestible to deer, thus the protein found in these will be readily available to the animal. If you see the words bypass protein, you know that protein escapes rumen degradation to be used farther down the digestive system and could provide growth benefits. However, you also know that microbial protein is vital, as it is the major protein source to the animal, so it is a need that must be taken care of first before there is any need to worry about bypass protein. There is little wonder why the word protein has become so popular in the deer hunting and management world. Protein plays a crucial role in all segments of the deer herd. A lack of protein in the diet will undoubtedly lead to a poorer quality deer herd. In many cases, protein is lacking in the natural environment, especially if you look at protein levels over time. Protein is highest when plants are young and growing and drops along with digestibility as the forage matures. However, deer require high amounts of protein throughout the entire spring and summer. The protein level found in natural food sources has been shown to average 8 percent to 12 percent, far lower than the 16 percent to 18 percent needed for maximum antler growth and doe lactation. Thus, a dramatic result can be seen when a highly digestible, high-protein food plot is added to supplement the deer’s diet — especially, if that food plot maintains a high protein level throughout spring and summer.


It might be nearly impossible to know everything thing about a given subject, but more knowledge is always better than less. Knowledge leads to better actions and, probably more importantly, leads to better questions. Although we know that protein is important in a deer’s diet, knowing the details on why, what and how can help you in your decisions on how to best use protein in your management plan.