Contraception in Zoo Mammals: Rumors and Realities
American Association of Zoo Veterinarians Conference 2007
Lisa A. Harrenstien1, DVM, DACZM; Anneke Moresco2, DVM; Cheryl S. Asa3, PhD; Ingrid J. Porton3, MS; Sally M. Boutelle3, MS; AZA Contraceptive Advisory Group3
1Oregon Zoo, Portland, OR, USA; 2Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, USA; 3Saint Louis Zoo, St. Louis, MO, USA


Contraception is the deliberate prevention of production of offspring. The simplest or most permanent methods of contraception can include housing males and females separately, or surgical alteration of anatomy such that sperm and ova cannot combine (vasectomy, ovarian or uterine removal, testicular removal, or tubal ligation). Temporary contraception is commonly employed in zoological species, retaining the ability to resume reproduction of genetically valuable individuals if management conditions change over time. Choices between the various available contraceptive techniques all involve assessment of risks, benefits, financial costs, behavioral costs, ethical considerations, practical limitations, technical abilities, and resources. An additional, very real component of contraceptive decision-making is the anecdotal or databased information that colleagues provide to the discussion. Each situation generates a different set of considerations when deciding upon the most appropriate contraceptive.

Contraceptive data summaries and recommendations are available via internet2 and in affordable published texts,1 but rumors contrary to the data still abound. Examples of the concerns and questions posed to the AZA Wildlife Contraception Center include: Are melengestrol acetate (MGA) implants now contraindicated for use? Are porcine zona pellucida vaccines effective for contraception? Can an animal that is administered a gonadotropin-releasing hormone (GnRH) agonist for contraception (leuprolide or deslorelin) be housed immediately and safely back with other animals? Can any male mammal be given a GnRH agonist for contraception or aggression control? Temporary contraception might be expensive; is it worth it?

Decades of available data and expertise should be incorporated into responsible decisions regarding contraceptive usage.

Literature Cited

1.  Asa CS, Porton IJ, eds. Wildlife Contraception: Issues, Methods and Applications. Baltimore, MD. Johns Hopkins University Press. 2005.

2.  Contraception Advisory Group of the American Zoo and Aquarium Association. 2007. Contraception Guidelines. Available at: Accessed on 5 April 2007. (VIN editor: Original link was modified on 1–18–2021).


Speaker Information
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Lisa A. Harrenstien, DVM, DACZM
Oregon Zoo
Portland, OR, USA

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