Besides surgical sterilization, contraceptives for wildlife include hormonal methods, fertility inhibitors such as immunocontraceptives, nicarbazin, VCD (4-vinylcyclohexene diepoxide), triptolide and nicarbazin. Hormonal methods, used in zoo animals and livestock, are based on synthetic hormones which bind to hormone receptors and disrupt reproduction. Those tested as wildlife contraceptives include levonorgestrel and […]

This depends on the contraceptive. Some contraceptives are available as oral formulations delivered in baits while others are delivered as injectable drugs administered subcutaneously or intramuscularly by hand or remotely delivered by syringe-darts via a dart rifle, and as subcutaneous implants.

This depends on the contraceptive. In some species, such as deer, GnRH-based contraceptives interfere with the normal antler cycle and should not be used in males. Orally-delivered contraceptives target both males and females.

In many species both males and females mate with multiple partners. If only males were targeted, a very high percentage of male infertility would be required to reduce population growth.

When injectable immunocontraceptives are administered during gestation, pregnancy normally goes to term and is then followed by infertility. GnRH-based vaccines do not affect pregnancy when administered to pregnant deer, horses, bison and wild boar. PZP-based vaccines are safe when administered to a wide variety of hooved […]

This depends on the species, on the route of administration and on the contraceptive. Injectable immunocontraceptives which are effective after a single dose, may last a lifetime or require re-administration every 1-3 years to maintain infertility. A single levonorgestrel implant maintains infertility in several marsupial species […]

When ingested, PZP and GnRH-based vaccines are digested like any other protein, so they are safe for human consumption. Pigeons treated with nicarbazin are also safe to eat, as this drug is quickly excreted.

Immunocontraceptive vaccines may cause injection site reaction in some species, similar to that produced by other injectable vaccines. In other species no side effects have been observed. Research on the potential welfare impact of hormonal methods on wildlife is ongoing. No welfare effects have been reported for nicarbazin.

PZP and GnRH-based vaccines are digested like other proteins, so they do not pose risks to predators or scavengers. As oral contraceptives delivered in baits may affect non-target species, bait dispensers have been developed for target species. These include rodent-specific boxes and squirrel-specific dispensers, and wild […]

Ovocontrol®, based on nicarbazin, is registered for pigeons. The GnRH-based immunocontraceptive vaccine GonaConTM is registered for white-tailed deer, feral horses, feral donkeys and prairie dogs. The PZP-based immunocontraceptives ZonaStat-H and ZonaStat-D are registered for horses and wild burros (H) and for white-tailed deer (D). ContraPest, based […]