breedingprogramm

Breeding Programmes

Goal
Every coordinated breeding programme aims at establishing long term self sustaining pop-ulations in captivity. Provided that original habitats are protected and maintained, these populations can be regarded as a resource for re-introduction programs or for support of wild populations.

Criteria
Criteria for the establishment of a breeding program are conservation status of species in their natural habitat, taxonomic uniqueness, the population size in captivity and chance of success for long term maintenance.

Policy
Breeding programs can be organized at regional or global levels. Every breeding program is managed by a species coordinator - a specialist (e.g. Biologist, Veterinarian) for the involved species. The coordinator keeps a studbook considering all individuals in those zoological institutions participating in breeding programs (e.g. EEP European Endangered Species Program, SSP Species Survival Plan). Population data are well documented on the Single Population Analysis and Record Keeping System (SPARKS) of the International Species Information System (ISIS), which supports analyzing demographical and genetic issues.

The coordinator is supported by a species specialist group, which includes several representatives from different zoos experienced in keeping the respective species. Together they evaluate the roles of individual animals and institutions within the breeding programme and make recommendations to future breeding actions. The following aspects are taken into account:

Genetics and Demography: Genetic variability is the basic requirement for long term capability of adapting to changing environmental conditions (Boer 1989). Specialists in population genetics postulate that, in theory, 20 – 50 wild founders are sufficient to maintain 90% heterozygosity of the source species for the next 200 years. Since the population of Przewalski’s horses is based on the small number of 12 founders, only 79% of the original genetic variability can be maintained by means of cautious management.

During first generations population size should increase quickly and after achieving optimum size become stationary, mortality and birth rate are supposed to equilibrate. The most favourable population has a pyramidal age structure. Inbreeding should be avoided.

Taxonomy: Species showing extended geographical distribution can develop various populations which are described as subspecies. The taxonomy of imported individuals should be determined prior to breeding recommendations, since subspecies can lack phänotypic differences or reveal only minor variation. Their biology e. g. annual reproduction cycles or migratory behaviour can differ and might be of genetic origin. Hybrids of subspecies will possibly lack the ability to survive under wild conditions. DNA analysis as well as demographic data can contribute to the identification of subspecies.

Back-Breeding

Extinct animal species like Aurochs ((Bos primigenius) have vanished completely, thus back-breeding programmes cope with other preconditions than programmes based on living species. Back-breeding aims at creating phenotypes resembling that of extinct species which in this case is possible, since domestic cattle maintained the genetic potential. But this process can last several years and is only viable by means of rigid selection. This sturdy cattle breed is applied for landscape care and contributes to nature conservation projects. Breeders are associated in Verein zur Förderung der Auerochsenzucht e.V. (VFA) (www.auerochsen.de). The Large Herbivore Foundation (www.largeherbivore.org) proposed a different spelling in order to distinguish the modern breed Aurox from the wild cattle Aurochs.