Chapter 6 



Maintaining Animal Diversity Offsite 



HIGHLIGHTS 



• Offsite maintenance of animal diversity includes selective breeding of wild 

 or domestic species and safeguarding genetic diversity through cryopreserva- 

 tion. For wild animals, the programs reinforce rather than replace efforts to 

 maintain diversity onsite. For domestic animals, programs try to maximize 

 usefulness of the animals while preserving their ability to adapt to changing 

 human needs. 



• Cryogenic storage could make a considerable contribution to the maintenance 

 of animal diversity. Properly frozen and maintained, sperm and embryos have 

 an expected shelf-hfe of hundreds of years. Although initial collection and pres- 

 ervation costs are relatively high, subsequent storage costs and space require- 

 ments are low. 



• The number of individual animals required to start a captive population or 

 a cryogenic store depends on a host of factors. Retaining 99 percent of a source 

 population's genetic diversity for 1,000 generations could require up to 50,000 

 animals, far too many to be practical under captive management. At a mini- 

 mum, however, several hundred individual animals are required for captive 

 breeding programs. 



• Breeding programs require the international transfer of animals, which risks 

 spreading pests and diseases. For most wild species, regulatory controls are 

 virtually nonexistent. Stringent controls are in place, however, for importing 

 domestic animals. Advances in diagnostic procedures and germplasm trans- 

 fer technologies are expected to facilitate the international movement of animals. 



• No organized program exists, either in the United States or internationally, 

 to sample, evaluate, maintain, and use available sources of animal germplasm. 

 Such a program is needed, in addition to programs to understand the repro- 

 ductive processes of wild animals, to develop local expertise in reproductive 

 biology and quantitative genetics, and to increase the number of captive main- 

 tenance and breeding facilities. 



OVERVIEW 



Obiectives off Offsite 

 Maintenance Efforts 



Offsite maintenance of animal diversity is de- 

 fined as propagation or preservation of animals 

 outside their natural habitat. The programs in- 

 volve control by humans of the animals cho- 

 sen to constitute a population and of the mat- 

 ing choices made within that population. The 



extent of control can vary considerably, but the 

 decision to remove individual animals from a 

 natural habitat implies a major increase in hu- 

 man involvement in propagation of a popu- 

 lation. 



Captive maintenance of wild species has be- 

 come progressively more important as increas- 

 ing numbers of species are threatened or en- 



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