Breed and Cull: Let’s Talk About a Taboo
American Association of Zoo Veterinarians Conference 2012

Christian J. Wenker1, Dr. med. vet.; Stefan Hoby1, Dr. med. vet.; Arne Lawrenz2, Dr. med. Vet.

1Zoo Basel, Basel, Switzerland; 2Zoo Wuppertal, Wuppertal, Germany


Population management in zoos and protected areas is a reality. Zoo veterinarians routinely apply reversible and irreversible contraception and methods are continuously updated.1 However, contraception excludes the animals from all aspects of reproductive behaviour (courtship, pair-bonding, mating, pregnancy, rearing offspring, mother-infant bonding, playing, and other socialization of the young by the adults and vice versa), and therefore also from its unique enrichment potential.5 We also need reproduction of zoo animals for long-term preservation of the widest possible genetic variety of endangered species. The application of contraception as the only method for population control in zoos is therefore controversial with regard to animal welfare and conservation, and the culling of surplus animals has to be considered a valuable alternative.3,4 Zoo’s attract the public (and raise its awareness for conservation issues) with animal babies which makes consequent killing of offspring a major emotional dilemma. Furthermore, cultural and legal aspects also need to be taken into account as well as the way of dealing with staff, public awareness and the media. The actual decision of culling an animal can only be made by a person who possesses the specific expertise and is familiar with the situation (e.g., the zoo veterinarian).2 Killing of surplus animals and information has to be done in a professional way. Zoo Basel sacrifies zoo animals and performs whole carcass feeding of Artiodactyla to carnivores. The procedures are supervised and controlled by the zoo vet. Body cavities are opened and meat is inspected by the zoo vet to ensure best quality and hygiene. The public is informed about it both actively and passively. The purpose of this paper is to encourage the discussion of this issue within the zoo community.

Literature Cited

1.  Asa, C.S., and I.J. Porton. 2005. Wildlife Contraception. Issues, Methods and Applications. Baltimore: The Johns Hopkins University Press.

2.  Hildebrandt, W. 2008. Zum Umgang mit überzähligen Tieren in Zoologischen Gärten – Besucherbefragung im Tiergarten Nürnberg und Zoo Leipzig. Dissertation, Institut für Tierschutz und Tierverhalten, Fachbereich Veterinärmedizin, Freie Universität Berlin,

3.  Richardson, D.M. 2000. Euthanasia: a nettle we need to grasp. Ratel, Journal of the Association of British Wild Animal Keepers. 27 (Vol. 3).

4.  WAZA. 2003. Consensus Document. Responsible Reproduction Management, Guiding Principles. Proc. Rigi Symp. 2003: 21–22.

5.  Wenker C., T. Dietrich, W. Hildebrandt, and O. Pagan. 2009. To kill or not to kill–the anti-contraception position. Proc. Int. Conf. Dis. Zoo Wild Anim. 44–46.


Speaker Information
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Christian J. Wenker, Dr. med. vet.
Zoo Basel
CH, Basel, Switzerland