Whitetail Genetics


Genetics and Antlers of White-tailed Deer

The role of genetics in antler development is one of the most misunderstood areas of deer management. Many of the public think that genetics and inbreeding are the reasons that big bucks of yesteryear are no longer common place. We do know that genetics is an extremely important component of the deer management formula. However, genetics is just one of the factors that governs antler development. Age, nutrition, disease, and injury are often more important contributors to a buck's antlers than is genetics.

To understand the role that genetics plays in antler development it is first necessary to understand the contributions other factors make to a buck's antlers. Most importantly, the animal has to have adequate nutrition. Without adequate nutrition a buck with the genetic background to become the world record white-tailed buck might be less than average. An example of the importance of nutrition was demonstrated by a nine year-old buck that was acquired for breeding in the Mississippi State deer research facility. When acquired the buck had been in a private deer facility in Missouri and had been fed a mostly corn diet the previous year. It should be noted that corn is a very poor quality food for deer except during periods of high-energy drain during cold periods of the year. It is high in carbohydrates but low in protein (about 8 percent). On the corn diet, the animal grew an 8 point rack, had a 17 inch inside spread, 18 inch long main beams, and a gross Boone and Crockett score of about 115. After being in the Mississippi State pens for one year on a normal 16% protein ration, the animal's antlers increased to 21 points, a 27.5 inch inside spread, 28 inch main beams, and a gross Boone and Crockett score of 210.

Age can also effect a buck's antlers dramatically. White-tailed deer do not achieve maturity until they are 5 to 8 years of age. Studies at Mississippi State have demonstrated the average buck achieves only about 10 percent of his potential antler development by age 1.5 years (when he completes his first set of antlers as an 18-month-old buck). We also have been able to demonstrate that there is little relationship between the first year antlers and the antler development a buck will have when he reaches the mature age classes of 5 years or older. This means a spike-antlered buck has a good chance of becoming a trophy-quality adult buck. By the time a buck has completed his second set of antlers he still has achieved only 25-35 percent of his potential antler development. At 3 years of age (few bucks live longer than this in Mississippi because of hunting pressure), a buck still only has achieved about 50 percent of his potential antler quality. It is not until 5 years of age that most bucks approach their full antler potential, and often, antlers don't reach their maximum size until 7 or 8 years of age (for captive animals raised under ideal conditions). Probably less than 1 out of 5,000 bucks would survive to the 6-year-old age class with the hunting pressure now across most of Mississippi. It is no wonder we don't see the quality of bucks that existed "back in the good old days," when hunting pressure was very low compared to today.

Another feature that may develop with age is an often-dramatic change in the conformation of a buck's antlers. Stories abound in sporting magazines about how hunters have pursued the same buck from a young age until they developed into full maturity. It is probably the exception, however, rather than the rule that a hunter could tell he was hunting the same buck from one year to the next. In watching our captive deer develop, a high percentage will experience significant antler conformation changes by the time they reach the older age classes and bear little if any resemblance to what their antlers looked like as 1, 2, or 3 year-olds. It is also the older age class bucks that begin to develop atypical points. A buck that has a perfectly symmetrical 8 point, as a three year-old, can conceivably have 16 or more points by age 6 years. However, some bucks develop their antler conformation at a relatively young age, and it certainly is not unusual for an 8 point yearling buck to remain an 8 point when mature.

Two other factors that effect a buck's antler conformation are injury and disease. Injury to a buck's antler while they are still in the velvet will often result in asymmetrical antlers with odd points, double main beams, or other abnormal characteristics. Generally, antler injuries of this type do not result in antler abnormalities the second and following years unless they occur near the base of the growing antler or to the skull. If the injury is near the base of the antler, the injury can result in abnormal development in subsequent years as well as the present year. Injury to other parts of the skeleton can also result in abnormal antler growth during subsequent years. It is well documented that skeletal injury to a hind leg will result in the opposite antler being malformed in the next and in subsequent antler growth periods. Injury to a front leg often results in the antler on the same side of the body being malformed.

Disease also can cause antler growth to be abnormal. The bluetongue and hemorrhagic diseases often occur during late summer when antlers are growing and cause antler growth to cease at that time. Bucks to which this occurs often have blackened, pithy antler tips for that year. Disease can also permanently restrict potential antler development. Nutritional and hemorrhagic can damage the digestive tract and prevent an animal from ever obtaining its optimum body condition and antler development.

Given proper nutrition, age and no injuries or debilitating diseases, it is genetics that determine the final development of a buck's antlers! Two deer can be raised together to 7 years of age under optimum nutrition and conditions. One may become a Boone and Crockett deer while the other may only develop into a mediocre 6 or 8 point deer. In this case, the genetic makeup Mother Nature gave them would determine the antler development. We know there are some geographical areas that consistently produce better quality antlers than others. We also know that, with the exception of antler injury, it is genetics that determines whether a buck will have typical or atypical antlers. Our research has shown that a buck does not always transmit his antler qualities to his offspring. For example, a buck with very poor antler qualities may produce offspring with very good antler qualities and vice versa. This means there is very little that can be done to practically manage genetics in a wild deer population because we cannot determine which deer will pass the superior genes to its offspring. Additionally, even if we could select a "superior" buck, 50 percent of the offspring's genetic information is supplied by the doe, and there is no way to identify the superior doe! Research at Mississippi State has demonstrated doe's are equally, or more important, than bucks to determining the offspring's antler qualities. This does not mean that we will not manage genetics of the white-tailed deer in the future. In fact, it is probable that we will do so through genetic introduction. However, we first need to better understand through research, such as that being conducted by Mississippi State, what is prudent and wise to do when considering manipulation of genetics in wild populations.