Memo on PZP: Support and Benefits for Wild Horse Management
Introduction to PZP
PZP (Porcine Zona Pellucida) is a fertility control vaccine that has been used for over 30 years to manage wildlife populations, including wild horses. It is supported by scientific research and endorsed by numerous organizations for its effectiveness and safety. This memo outlines the support, benefits, and scientific backing for PZP in wild horse management.
Support for PZP
- 30 years of science documents its safe and effective use on multiple wildlife species, including wild horses.
- National Academy of Sciences recommended.
- Over three dozen organizations, including the nation’s leading animal welfare and wild horse protection organizations, endorse it.
- Used successfully to manage numerous BLM herds, including Fish Springs horses in Gardnerville, NV.
Benefits of PZP
- Preserves natural behaviors by creating an immune response that prevents fertilization without affecting the reproductive hormones that drive behavior.
- Safe for pregnant mares, causing no harm to the fetus.
- Delivery by remote darting.
- 90+% efficacy.
National Academy of Sciences on Fertility Control
“The most promising fertility-control methods for application to free-ranging horses or burros are porcine zona pellucida (PZP) vaccines, GonaCon™ vaccine, and chemical vasectomy… Preserving natural behaviors is important, so GonaCon seems more appropriate for use in females in that some research has suggested that female sexual behavior continues. GonaCon can be used and has been tested in males, and its effects are similar to those of chemical castration. However, further studies on behavioral effects of this product are needed.” (P. 6-7)
Table from Page 7 of NAS report: