Origins of PZP
The first report on
the use of PZP in feral and domestic animals (horses) was
in 1989 (Journal of Reproduction and Fertility; 85:. 19-29.
Liu, Bernoco and Feldman). Since then, this vaccine has been
successfully used on a number of wildlife species.
Scientifically documented projects have included, wild horses
in Nevada (Turner, Liu and Kirkpatrick), the White-tailed
deer in Ohio (Turner, Liu and Kirkpatrick), the American black
bear in South Dakota (Lane and Liu), the tule elk in California
(Stoops and Shideler), the South African elephant (Fayrer-Hoskens
and Bertschinger) and llamas and alpacas in Peru (van Leeuwen
The procedure for the production of PZP was developed by UC
Davis researcher, Dr. Jerry Hedrick and applied to domestic
and feral animals by Dr. Irwin Liu. Since 1987 these researchers
have provided considerable quantities of PZP to various governmental
and private agencies throughout the world for the experimental
purposes of contracepting and humanely controlling animal
overpopulations where applicable. The agencies that were provided
with the PZP vaccine include: The Humane Society of the United
States; the Science and Conservation Center; Bureau of Land
Management, Dept. of Interior; Santa Cruz Island Foundation;
National Park Services, Dept. of Interior; The National Zoological
Research Institute, Italy; University of Madrid, Spain; University
San Marcos, Peru; The Institute of Zoology, Beijing, China;
and The National Wildlife Research Center, USDA-APHIS, Colorado.
The UC Davis researchers are continuing to perform collaborative
research with these and many other agencies and nonprofit
organizations not mentioned above.
While the UC Davis researchers are not commercially marketing
the PZP, they hope to generate funds for continuing research
in PZP through marginal, laboratory replacement and personnel
costs for the production of PZP.
The UC Davis researchers are continuing to develop PZP and
hormone based agents aimed at effective and humane methods
for contraception and sterilization of animals. These methods
are being developed to serve as alternatives to current methods
of controlling overpopulation of domestic and wildlife animals.
Inquiries regarding the use of PZP and its
availability can be made to
Irwin KM Liu, DVM, Ph.D.