Date of this Version
Overabundant deer herds, particularly those in urban or suburban settings, present serious problems for wildlife managers, landowners, and the general public. Problems include increased numbers of deer-vehicle collisions, increased damage to ornamental and native plants, aggressive behavior toward humans by bucks during the rut, greater potential for disease transmission among deer, and reduced nutritional status of deer. Traditional methods of population control, such as hunting, often are impractical or illegal in such settings. The development of safe and effective wildlife contraceptives is needed to control overabundant wildlife populations in situations where traditional management tools cannot be employed.
The single-shot, multiple-year GonaCon™ vaccine will be a useful tool for the management of enclosed or urban/suburban wildlife populations, such as deer. GonaCon™ still has limitations, however, especially the need to capture and inject each animal.
GnRH Immunocontraception—The GnRH vaccine stimulates the production and release of GnRH-specific antibody from the B-cells into the bloodstream. The antibody circulates throughout the body, and when it reaches the capillary region of the hypothalamus, it comes into contact with GnRH that has diffused into the capillaries after being produced in the hypothalamus. Binding of GnRH to the specific antibody forms large immune-complexes that travel down the hypophysial stalk. Because of their large size, however, the immune-complexes are unable to diffuse out of the blood at the pituitary capillaries. Instead, they remain in the venous blood and leave the pituitary without stimulating the release of LH and FSH. Without the LH and FSH that normally stimulate the synthesis of steroids in the reproductive organs, animals of both sexes remain in an asexual, nonreproductive state. As long as there is sufficient antibody to bind all GnRH circulating in the hypothalamic/pituitary portal system, all sexual activity will be suspended and animals will remain nonreproductive.