Issue of the Week: Deer Contraception

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White-tailed deer management and the use of contraception has been a topic of heated debate over the last few years. In some areas, deer populations have exceeded population management goals, which have led to an increase of deer related damages. State Farm estimates that over 1 million vehicle collisions yearly are caused by deer, costing more than $4 billion in vehicle damage.

In the absent of a management strategy, wildlife populations can increase to numbers that can cause problems to humans. Not only does overpopulation damage human’s property but can also harm their environment and other species. As a result, alternative solutions must be found. The alternative solution currently being used is contraceptive agents.  These contraceptive agents help manage deer numbers and are becoming increasingly popular as a possible management tools in suburban areas.

However, these agents are popular despite the fact that the products currently being used are experimental, costly, require multiple applications to be effective, and are not considered to be effective. With sterilization, the population is not immediately impacted. Rather the population will stay the same until natural mortality starts taking affect.

There are a few different methods to render a deer infertile. The first being surgery. Currently, Fairfax, VA is the first municipal in Virginia that uses surgical sterilization to control its deer population. Dr. Anthony DeNicola currently leads the project and expects Fairfax to maintain its population in five years. Under Dr. DeNicola’s program, the female deer undergoes surgery to remove their ovaries.

Another method is immunocontraception which “vaccinates” a deer to stimulate its immune system to produce antibodies against certain proteins involved in fertilization. Researchers have discovered that Porcine Zona Pellucida (PZP) has the most potential as a fertility control agent with animals such as coyotes or wild horese. However, PZP vaccines have several drawbacks with their use in white-tailed deer management because they do not prevent the production of sexual hormones and can have serious affects on deer hormone levels and female behavior,  (Turner et al. 1992, 1996; Miller et al. 1998). An additional problem with immunocontraception is the upkeep. It often requires multiple treatments the first year and an annual treatment thereafter. Tracking the animal and injecting the treatments may become costly and the failure rate may increase. Alternative vaccines such as Gonadotropin Release Hormone Vaccines (GnRH) and GonaConTM are also being examined.

In light of these findings,  some state wildlife agencies see hunting as the more efficient and cost effective way to manage deer populations. It has not only been proven to be the most effective method but it also helps out state and local economies. State wildlife agencies depend on this revenue from hunters and the local economies benefit from the expenditures hunters spend before they head out into the field. Hunting is a traditional form of recreation that remains to be the most efficient and cost-effective way to manage wildlife populations at targeted levels.

Though conservationists differ in their choice of management tools, a general norm is needed to curb growing deer population numbers. Many still choose hunting as the most effective strategy but the opportunities for alternatives tools should still be examined. Contraception is relatively new in the world of wildlife management and only scientific research will provide the backing it needs to become a general practice for conservationists. With the new trials being used in Virginia and other highly populated areas of North America, we will eventually learn what’s best to manage our country’s swelling deer population. Fertility control agents are not effective in reducing wild populations and are more costly than hunting.  While a managed hunt may be costly, it is a proven way to reduce a population, whereas fertility control can, at most, stabilize it. In most cases, fertility controls do not raise enough funds for their oversight agency.

We apologize for last week’s absence. Convention kept us busy, but we are back. Stay tuned for Thursday’s update on all the 2014 Convention fun.

Twice a week, SCI Foundation informs readers about conservation initiatives happening worldwide and updates them on SCI Foundation’s news, projects and events. Tuesdays are dedicated to an Issue of the Week and Thursday’s Weekly Updates will provide an inside look into research and our other science-based conservation efforts. Follow us on Facebook and Twitter for more SCI Foundation news.

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