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Open nucleus breeding systems

Published online by Cambridge University Press:  02 September 2010

J. W. James
J. W. James
Affiliation:
School of Wool and Pastoral Sciences, University of New South Wales, Kensington, Australia 2033
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Summary

A theoretical analysis of open nucleus breeding systems, in which there is some introduction of breeding females to the sire breeding nucleus, is presented. Numerical analysis of a discrete generation model shows that the rate of genetic gain may be increased by 10 to 15% by opening the nucleus when selection intensity in females is low. In sheep and beef cattle breeding the optimal structure would be to have about 10% of the population in the nucleus, to get half of the nucleus female replacements from the base population, and to use all nucleus-born females not needed as nucleus replacements for breeding in the base population. The genetic gain, however, is not very sensitive to variation in these parameters. The rate of inbreeding in such an open nucleus would be about half that in a closed nucleus of the same size.

Type
Research Article
Information
Animal Production , Volume 24 , Issue 3 , June 1977 , pp. 287 - 305
Copyright
Copyright © British Society of Animal Science 1977

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References

REFERENCES

Bichard, M. 1971. Dissemination of genetic improvement through a livestock industry. Anim.Prod. 13: 401–11.Google Scholar
Bichard, M., Pease, A. H. R., Swales, P. H. and özkütük, K. 1973. Selection in a population with overlapping generations. Anim. Prod. 17: 215–227.Google Scholar
Jackson, N. and Turner, H. N. 1972. Optimal structure for a co-operative nucleus breeding system. Proc. Aust. Soc. Anim. Prod. 9: 55–64.Google Scholar
James, J. W. 1976. Maximising a function of the selection differential. Theoret. Appl. Genet. 47: 203–205.CrossRefGoogle ScholarPubMed
Robertson, A. and Asker, A. A. 1951. The genetic history and breed-structure of British Friesian cattle. Emp. J. exp. Agric. 19: 113–130.Google Scholar