Cryo-techniques and storageThe possibilities to store genetic material over very long periods through application of cryo-techniques and very low temperature storage represent extraordinarily valuable contribution to conservation and use of farm animal genetic resources. The techniques used for deep-freezing semen were developed around 1950 and rapidly became standard, playing a major role in the artificial insemination of cattle. The technique Artificial insemination using deep frozen semen represents by far the predominant method for breeding cattle, and is also used for sheep and increasing numbers of horses and other species. Deep freezing embryos was made possible by employing an improved technique during the 1980’s, when embryo transfer was also developed to become a routine method for breeding various domestic species, especially cattle. The technique used to deep-freeze genetic material and maintain good fertility is constantly being improved. Differences still exist among species regarding successful outcomes, but for many species [cattle, sheep, pig, goat, horse, poultry, rabbit, dog and fish (at least some species)] the techniques have become routine. Storing somatic cells represents an alternative technique, but has yet to be sufficiently developed so that it could serve as a secure basis to regenerate a breed in the same way that semen and embryos can be stored and used. This technique has tremendous potential however as evidenced by the results obtained with the sheep ‘Dolly’ and additional subsequent examples. A further advantage of cryo-techniques is that semen can be sexed and sex determination of embryos is also possible. This can be of great importance in conservation efforts. Nordic use Cryo-conservation represents an active component in the conservation measures in all Nordic countries. In the case of cattle, it has been in operation almost since the technique was developed, commercial breeding organizations having stored semen doses long-term for all bulls used in breeding programmes. In addition to the security represented by a genebank, cryo-conservation provides a large, high quality biobank for research purposes. Different programmes also operate where semen is collected from a number of bulls of endangered breeds for use in breeding. Security/costs As a component of gene banking, cryo-stored material is often irreplaceable, requiring that storage is thoroughly secure. Because of this, many countries have chosen to split the physical storage (nitrogen containers and contents) between two or more locations to ensure that the genetic material is not lost even in the event of unexpected catastrophic events. Cryo-storage of genetic material is expensive and funds are often limited. In the Nordic countries the commercial breeding organizations take responsibility for most semen storage for the principal breeds and also usually fund activities concerning collection, deep freezing and storing genetic material of threatened breeds. Responsible: Anne Præbel |
