Long term conservation of semen and embryo can be achieved through freezing. Cryo-conservation is therefore a complementary tool for managing live animals and preserving their genetic diversity. Routine freezing and semen conservation is a viable technique for most domestic species (conservation period over forty years for catle).

It is also possible to freeze ruminant and rabbit embryos, although embryo freezing being relatively newer than semen freezing, the conservation period is more difficult to evaluate.

The preservation of a sample which is representative of the genetic diversity of a breed requires semen or embryo collection from a minimum number of breeding animals, which varies depending on the species concerned. For example, a cattle breed can probably be recreated with 1000 doses of semen collected from 25 different sires or 300 asexual embryos provided by 90 donor animals. Quantities must however be doubled to enable storage on two different sites, i.e. 2000 doses of semen or 600 embryos in total.

A national Cryobank (in french) for domestic animal semen and embryo conservation has been created in 1999. A special effort must be made to collect material from low population size breeds. Ultimately, the national Cryobank should accommodate representative samples of genetic diversity (semen or embryos) for all French domestic animal breeds.