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Inbreeding arising through artificial insemination and natural service in Welsh black cattle

Published online by Cambridge University Press:  02 September 2010

J. H. Watson
J. H. Watson
Affiliation:
Department of Agriculture, University College of North Wales, Bangor
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Summary

Current rates of inbreeding due to A.I. and natural service are estimated in Pedigree Welsh Black cattle.

Since 1948, 27 sires have been used in A.I., 16 of which have a common male ancestor. Four sire-son pairs and two pairs and one trio of half-brothers have been in recent use. Two-thirds of the bulls and heifers bred by A.I. and registered in 1960 were sired by 4 bulls. Since 1954 progeny of two A.I. sires who are father and son, were preferred for registration.

Pedigree analysis of a sample of 128 bulls showed that those bred by A.I. were, on average, 2·80% inbred, compared with 2·32% for those from natural matings. In a sample of 166 heifers corresponding values were 0·82% and 1·17%.

One herd, through natural service, contributed 12% of the genes of a sample of bulls and heifers. Four other herds were outstanding for the number of males they provided. The average inbreeding of their young, registered bulls was estimated to be 7·04%.

The widespread use of the descendents of one bull, both in A.I. and natural service, led to 94 cases of inbreeding in the third and fourth ancestral generations of the pedigrees of animals in the sample.

It is concluded that the short term consequences of using a small number of bulls in A.I. measured in terms of inbreeding, are no different from those in natural service and that inbreeding depression in traits of commercial importance would be undetectable.

Type
Research Article
Information
Animal Production , Volume 5 , Issue 2 , June 1963 , pp. 209 - 214
Copyright
Copyright © British Society of Animal Science 1963

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References

REFERENCES

Clayton, G. A., 1956. Aspects of breed structure in pedigree British Shorthorn cattle. Proc. Brit. Soc. Anim. Prod., 1956, p. 107.CrossRefGoogle Scholar
Falconer, D. S., 1960. Introduction to Quantitative Genetics. Oliver & Boyd, Edinburgh.Google Scholar
Lush, J. L., 1946. Chance as a cause of changes in gene frequency within pure breeds of livestock. Amer. Nat., 80: 318.CrossRefGoogle ScholarPubMed
Robertson, Alan & Rendel, J. M., 1950. The use of progeny testing with artificial insemination in dairy cattle. J. Genet., 50: 21.CrossRefGoogle ScholarPubMed
Robertson, Alan & Asker, A. A., 1951. The genetic history and breed structure of British Friesian cattle. Emp. J. exp. Agric., 19: 113.Google Scholar
Robertson, Alan, 1954. Inbreeding and performance in British Friesian cattle. Proc. Brit. Soc. Anim. Prod., 1954, p. 87.CrossRefGoogle Scholar
Wiener, G., 1953. Breed structure in the pedigree Ayrshire cattle population in Great Britain. J. agric. Sci., 43: 123.CrossRefGoogle Scholar
Wright, S., 1923. Mendelian analysis of pure breeds of livestock. I. The measurement of inbreeding and relationship. J. Hered., 14: 339.CrossRefGoogle Scholar
Young, G. B., 1953. Population dynamics of the Dexter breed of cattle. J. agric. Sci., 43: 369.CrossRefGoogle Scholar