A nonlethal method of population management which focuses on reducing the birth rates of wildlife rather than increasing the mortality rates.1

The study of wildlife contraception dates to the 1960s when synthetic steroids were being investigated for their contraceptive use.2 Surgical contraception research has been ongoing since the 1970s.17 During the mid-1980s research into the use of immunocontraception emerged.3

Contraceptive methods for wildlife management include fertility inhibitors such as Nicarbazin, surgical, hormonal, and immunocontraception.4 15

Nicarbazin is a compound that causes a reduction in hatchability and egg laying due to increased membrane permeability between the egg white and egg yolk.2 This oral fertility inhibitor is reversible and is cleared from the body after 48 hours.1

Surgical methods of contraception include tubal ligation, tubal transection, ovariohysterectomy, ovariectomy, gonadectomy, vasectomy and salpingectomy. While most of these procedures are permanent, tubal litigation is reversible.5 15 18

Hormonal methods of contraception include progestins, which disrupt reproductive processes in males and females.16 There are oral progestins as well as depot injections containing progestin that regulate contraception. Deslorein implants are an example of a GnRH-agonists which have been used on captive wildlife to inhibit reproduction.

An immunocontraceptive vaccine induces antibodies against proteins or hormones essential for reproduction.14

Porcine zona pellucida (PZP) vaccine and gonadotropin-releasing hormones (GnRH) vaccine are both examples of immunocontraceptive vaccines.1

These vaccines are injected Intramuscularly via syringe-darts shot by dart rifles or injected by hand. They can also be injected using bio-bullets.4

Yes, PZP and GnRH-based vaccines are digested like any other protein, so they never enter the food chain; they do not pose a risk to predators or humans.4 13