Immunocontraception of captive exotic species: V. Prolonged antibody titers in Dall sheep (Ovis dalli dalli) and domestic goats (Capra hircus) immunized with porcine zona pellucida.

Native porcine zona pellucida (PZP) immunocontraception has been used to inhibit fertility in more than 80 species of ungulates, although the duration of contraception efficacy varies among species in both Perissodactyla and Artiodactyla. This study examined anti-PZP antibody titers in Dall sheep and domestic goats at the Milwaukee County Zoo, and also Himalayan tahr and Armenian Mouflon sheep at the San Diego Zoo Safari Park, and, for comparison, Altai wapiti, lowland wisent, Javan banteng, and southern pudu at the San Diego Zoo Safari Park, all were given a primer dose and booster dose of PZP. Of the San Diego Zoo Safari Park animals, the 4 comparison species demonstrated the typical 1-yr pattern of anti-PZP antibodies, whereas the Armenian sheep and Himalayan tahr showed prolonged (2-3 yr) antibody responses after a single primer and booster dose. The Dall sheep and domestic goats had significantly longer durations of antibody titers (3 yr) from a single year's treatment (primer plus booster). Analysis of the data indicates that Armenian sheep, Himalayan tahr, Dall sheep, and domestic goats have prolonged responses, and are more sensitive to PZP in that they produce a protracted antibody response.

Contraceptive vaccines for wildlife: a review.

Wildlife, free-ranging and captive, poses and causes serious population problems not unlike those encountered with human overpopulation. Traditional lethal control programs, however, are not always legal, wise, safe, or publicly acceptable; thus, alternative approaches are necessary. Immunocontraception of free-ranging wildlife has reached the management level, with success across a large variety of species. Thus far, the immunocontraceptive research and management applications emphasis have been centered on porcine zona pellucida and gonadotropin-releasing hormone vaccines. Contraceptive success has been achieved in more than 85 different wildlife species, at the level of both the individual animal and the population. At the population management level with free-ranging species, the primary focus has been on wild horses, urban deer, bison, and African elephants. The challenges in the development and application of vaccine-based wildlife contraceptives are diverse and include differences in efficacy across species, safety of vaccines during pregnancy, the development of novel delivery systems for wild and wary free-ranging animals, and the constraints of certain non-contraceptive effects, such as effects on behavior. Beyond the constraints imposed by the public and a host of regulatory concerns, there exists a real limitation for funding of well-designed programs that apply this type of fertility control.