Abstract

Issues of carrying capacity and resource availability often limit captive propagation programs. Contraception can be used as a management tool to reduce, stabilize, or control the growth of animal populations. The use of PZP immunocontraception as a management tool for nondomestic ungulates was initiated at the San Diego Wild Animal Park in 2002 and continues to the present time. The overall goal is to reduce the number of births/herd/year while maintaining genetically viable populations. Most treated animals are housed in large mixed species field enclosures with multiple males and are vaccinated by remote delivery of a projectile dart. To date, 138 individuals of 26 different species have received a total of 351 doses of PZP. There has been no known mortality associated with the use of PZP in subadult or adult animals. Morbidity is rare but includes one femoral fracture, two lamenesses requiring hospitalization, and three sterile abscesses (which occurred in the same individual regardless of the adjuvant used). Since males are present in the herds year round, pregnancy status of an individual is not always known. A review of records indicates that animals were vaccinated during all stages of gestation. The use of PZP lengthened the interbirth interval in some species and reduced herd fertility rates (total number of births/total number of females in the exhibit in a given year). Herd fertility rates identify trends as there is constant population influx and efflux. Serum samples are saved opportunistically to measure anti-PZP antibodies. Duration of effectiveness of PZP varies on an individual and species basis. Prospective studies to document reversibility in the various taxa are needed.

Acknowledgments

We thank Veterinary Services and the Mammal Departments of the San Diego Wild Animal Park for their assistance and support.