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Antler Growth & How You Can Help

Deer hunters hunt for many different reasons, that is understandable and hard to argue with.  What about trying to produce the bucks with the largest racks possible for hunting purposes?

Deer antlers are captivating and upright humans have had a desire for them since cave paintings were created.  Antlers are the fastest growing bone known.  Antlers are obviously different than horns, so what does it take to grow antlers and what can you do to encourage more growth on your deer lease or hunting ranch?

Unlike horns, antlers are grown and shed annually.  The antler growing cycle for whitetail bucks lasts only 128 days, or just over four months.  Yes, a spike and a Boone and Crockett grow their racks in the exact same timeframe!  How can this happen and why are some years better than others when it comes to antler development?

Mother Nature is incredible.  She mandates that the whitetail buck’s antlers are secondary to the health of the body.  The body takes precedence, or priority, over antlers in regards to bone health, internal organ health, protein and mineral consumption and overall total physical health.  This means that if the buck’ s body is lacking in nutrition or minerals or otherwise stressed, the antlers will suffer.

A buck usually comes out of the rut in physically stressed condition.  Some bucks can lose 30% of their total body weight during the rigors of the rut and they are tired, sore, perhaps injured and in need of immediate repair.  After the breeding season is complete, the antlers are cast, or shed, and testosterone production is reduced severely.  This is Mother Nature’s way of helping the buck to regain his health and eventually storing fat in preparation for next winter’s rutting season all over again.  Antlers are used as tools to determine mating privileges, rights, and for dominance establishment.  After the breeding season, the antlers are no longer needed and they are shed and the cycle continues again.

When the bucks shed their antlers, the 128 day antler growing cycle begins approximately one week after shedding.  Upon antler shedding, the raw pedicles heal over to protect the open wound and soon thereafter the new set of antlers begin to grow.  If the buck’s body is still recuperating and healing, the antler growth will be slowed as protein, minerals, vitamins and blood flow are redirected to the body recovery effort.  Once the body recovery effort is complete, those valuable antler-growing nutrients are redirected into antler growth.  The 128 antler-growing clock has been running, so the longer it takes the buck to return to good health, the less time he has to produce the current year’s set of antlers.  So, the condition of the buck’s body as he comes out of the rut is directly proportion to the quality of the rack he will be wearing the following hunting season!  Clear as mud?  The clock begins upon shedding and the sooner he begins to grow his antlers, the more time and growth he can produce in that period of time, resulting in longer tines, extra points, more mass etc.

Now, all of this antler growing process is also controlled by age and genetics, but this article is an example of the nutrition portion of the pyramid requirements for large antlers—genetics, age, and nutrition.  With age and good genetics, a buck can still grow a poor set of antlers if he is nutritionally stressed.  Or a buck with poor genetics, good age and nutrition will just grow a big set of poor antlers as he lives up to his full genetic potential.  The three requirements must all be met to produce a large set of antlers.  Antlers are genetically based and environmentally influenced.

What can we do on the ranch or lease to help the bucks out of the rut in the best possible physical condition?  First is balancing the total herd with the available habitat.  Fewer deer will have more food to eat and they will be healthier, that is an easy one.  Keeping the adult sex ratio tight is also recommended so that the females are bred during their first estrus cycle so that the fawns are born in the optimum time of year.  The balancing of the herd with the habitat is not quite as easy because this depends on rain and weather patterns.  The amount of available forage the habitat produces is a moving target.  In good rainfall years, the habitat can produce an excess of usable forage plants and that is why larger antlers are produced in wet years.  In poor rainfall years, the habitat can not produce enough usable forage plants for the animals and that is why smaller antlers are produced in wet years.  The manager must be aware of the habitat condition coming into and out of each deer season and make adjustments accordingly.  So, don’t get stuck in the habit of shooting X amount of bucks and X amount of does each and every year because the habitat is changing and so must the animal population that relies on it.

Obviously, cattle numbers must follow this same strategy as the deer harvest.  Cattle are much easier to manage than deer, so moving cattle into different pastures, rotating them more often or simply reducing the herd is a very quick and easy fix.

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Habitat management techniques that result in forage plant regrowth is also a valuable tool to help produce “extra” forage for deer.  Shredding, aerating, fallow discing and prescribed burning are good examples of this technique.  When most deer forage plants are top-removed, they resprout from the bottom and create more of a “bush effect”.  The extra limbs and stems produce extra leaves and the entire plant is now lower to the ground and allows for increased forage accessibility and availability.  The tall, thick stands of eight foot tall brush is little value to deer, but if you top removed that same brush, it would provide tons of usable, palatable, nutritious forage for deer without killing the parent plant.  The plants may be re-stimulated every three or four years for continuous and on-going forage production with very efficient per acre costs to the manager.  Keeping your deer woods in a mosaic pattern of regrowth is ideal for many other important reasons, but none are as important as improved foraging for your bucks in order for them to recover as quickly as possible so they may begin their new antler growth again.  The clock is running, how are your bucks doing right now?

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Antler Growth 101

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Who out there can honestly say that deer antlers don’t get them excited? Whether we manage deer as a profession or a passion, growing bucks with the big antlers is on our minds somewhere down the line. From the earliest drawings of our ancestors on cave walls, we have always had a fascination with antlers–their size, their shape, their oddities, their growth. Why else would we get up well before daylight and brave the harsh elements to pursue antlers and their owners?

But, do you fully understand the antler growing cycle from start to finish? It is an amazing process for sure and something all serious deer managers need to understand and appreciate if growing big antlers are your goal.

What makes an antler and antler, and not a horn?

Antlers differ from horns in that they are shed, or cast, each year and annually reproduced. Antlers are made of bone while horns are made of keratin, the same material your fingernails are made of. Horns are a thin sheath grown over a portion of the skull while antlers are completely separate of the skull, held on only by a small section nourished by vitamins and minerals with the ability to start and stop growth. Horns grow continuously while antlers grow for only 128 days. Antlers are the fastest growing tissue in the animal kingdom and can be grown only by deer and other Cervids. Horns are grown by cattle, goats, sheep and antelope.

Now, let’s take a closer look at HOW antlers are actually grown.

Antlerogenesis is the term that describes the annual physiological production of antlers. It is regulated by a series of interconnected processes that are important to understand. Antler growth is primarily regulated by testosterone levels. The testosterone levels in a buck’s body are regulated by photoperiod, or length of daylight. And length of daylight is regulated by the seasons that occur from the tilting and rotation of the Earth. Because of all of this, the antler growing process lasts only 128 days and cannot be extended or expanded.

When first born in the spring time, a buck fawn has small indentions and hair swirls on the frontal bone of his skull. At about four months of age, increased testosterone levels help to produce small, flat platforms called a pedicles. Pedicles provide the structural base for, and the foundation of, future antler development. A buck fawn born early in the spring and living under good nutritional conditions will have noticeable, hairy bumps during his first winter. The hairy bumps are not true antlers but instead dormant pedicles until he is old enough to produce “real” antlers. At approximately ten months of age, the young buck’s testosterone level increases enough to produce his first set of antlers. When fall arrives, this little buck will be about eighteen months of age, and referred to by deer managers as a “yearling buck.” Under ideal conditions and with good genetics, his first rack can have many points but most range from two to six points on average.

As antler growth begins, the underlying pedicle gives rise to new antler material, which at this point is a semi- firm tissue composed of approximately 80% protein. This growing material is cartilage-like and full of blood vessels. The nutrient-rich transporting blood vessels rise up through the pedicle as well as form the soft lining around the outside of the growing antler. The tiny little blood vessels and protective hairs are what we refer to as velvet when a buck is actively growing antlers. Blood vessel density and capacity is what “feeds” the growing antlers. A healthy buck produces and maintains a high volume of blood vessels, while one whose body is stressed will not. The velvet is also full of a dense network of microscopic nerves. The nerves make the velvet covered antlers sensitive and helps to protect the soft growing tissue against damage. The nerves may also make the buck aware of how his antlers are shaped, which will be useful when stripping the velvet and sparring with competing bucks. The visible grooves on the base and beams of hardened antlers are the impressions left by the blood vessels as it grew in velvet.

What role does nutrition play?

Normal dietary intake cannot supply enough nutrients and minerals to support the rapid growth rate of the new antlers. Remember, antlers are the fastest growing tissue in the animal kingdom, and consequently require huge demands on the buck’s body for quick nutrients and energy. The buck’s body actually recalls and transfers calcium and phosphorus (the primary building blocks of antlers) from the entire skeletal system and the blood transports these minerals to the growing antlers via the new blood vessels. Research has shown that the bulk of the minerals are taken primarily from the ribs and sternum area creates a temporary condition of osteoporosis–a degenerative bone disease common in older humans.   In deer, however, this condition is only temporary (unlike in humans) and once the antlers are fully mineralized, the bone density returns to the normal pre-antler growth levels once again.

As the days become shorter, the pineal gland (attached to the brain) senses the shorted daylight/photoperiod (through the optic nerve) and sends the signal to the testes to increase testosterone levels. As testosterone levels increase, the antlers become mineralized and begin to harden.   Once completely mineralized the ever-increasing testosterone levels cause the blood flow to cease and the velvet dries and begins to split and crack open. The buck then begins to rub his antlers on small trees and shrubs to remove the dried velvet and this rubbing action mixes the brown pigment in the plants (called tannins) with the remaining dried velvet blood to create the familiar brown color commonly found on antlers. Bucks that either rub on plants without tannins or held in captivity without the ability to clean their antlers will have snow white antlers when stripped of velvet.

Testosterone levels peak in the breeding season and decline shortly thereafter. The decrease in testosterone triggers osteoclasts that erode the base of the antler at the pedicle, resulting in the antler falling to the ground. Osteoclasts are bone cells that are associated with the dissolution of unwanted bone. Once the antlers are cast, the amazing growth cycle begins all over again in approximately two weeks.

The scab that forms over the wound left by the cast antler heals and becomes covered with fine, thin hairs. The fine-haired skin forms the beginnings that will nourish and protect the growing antlers for the next four months.

Management implications to consider:

  • Mother Nature mandates that the whitetail buck’s antlers are secondary to the health of the body. The body takes precedence, or priority, over antlers in regards to bone health, internal organ health, protein and mineral consumption and overall total physical health and healing. This means that if the buck’ s body is lacking in nutrition or otherwise stressed, the antlers (and the 128 day growth cycle) takes a back seat nutritionally until the body is fully healed and recovered. Managers must make certain that the bucks exit the rut in as good of physical condition as possible so that healthy antler growth begins on the first day and is not delayed in order to maximize antler growth time and energy.
  • Maintaining a tight adult sex ratio ensures that the does get bred on their first or second estrus cycle and ends the stressful rutting activity. Unbalanced ratios extend the rutting activity for months, thereby nutritionally stressing the bucks for longer than necessary and causing them to delay their antler growth cycle while they rebuild body condition.
  • Remember, antlers are directly influenced by the health of the buck growing them, and his health is influenced by the quality and quantity of nutritious forage.   Nutritionally speaking, the early spring and fall are the best times for a deer. The worst are summer and late winter when forage is lower in quality and quantity. In order to keep the nutritional plane more level and constant, maintain the herd at or below carrying capacity to ensure all animals have more than enough to eat every month of the year.
  • Manage your habitat to provide deer with the most nutritious and palatable browse and forage for your area. Good habitat = healthy deer = better antlers.
  • Supplemental feeding is just that, a supplement to the deer’s diet. It assists when and where needed and it makes a positive impact. If it is legal and you can do it, you should strongly consider it for maximum antler growth.
  • If you do need to offer supplemental feed, do it year-round. A buck is either growing antlers or preparing his body to grow antlers 365 days a year.
  • Calcium and phosphorus are the building blocks of antlers. Make sure you are offering effective amounts of each and in a balanced 2:1 ratio for maximum efficiency.
  • Calcium improves weight gain and feed utilization, which in turn promotes a healthier buck capable of growing antlers to his full genetic potential.
  • Phosphorus improves growth rate, feed utilization and appetite and combines with Calcium to form essential bone mineral salt.
  • Vitamins such as A, E and D stimulate the immune system, improve bone growth, improves sperm production and assists with bone mineralization.
  • Copper, Manganese and Zinc improves antler mass and tine length, stimulates the immune system, reduces sterility, and aids in bone formation.

 

As you can tell, antlerogenesis is an incredibly detailed process. Antlers are, basically, grown year around from a nutritional perspective and it would do managers well to keep that in the front of their minds. Habitat and herd management all have direct and lasting nutritional impacts and those impacts will affect future antler growth.

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