Hostname: page-component-5c6d5d7d68-ckgrl Total loading time: 0 Render date: 2024-08-09T13:56:59.315Z Has data issue: false hasContentIssue false
  • English
  • Français

Development of a synthetic pig sire line by selection with immigration 1. Results of selection and heritability estimates

Published online by Cambridge University Press:  02 September 2010

A. J. Webb  and
J. W. B. King
A. J. Webb
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
J. W. B. King
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
Get access

Summary

Starting in 1959 from a crossbred foundation, a specialized synthetic sire line has been developed with the aim of making rapid genetic improvement in lean meat production. Within-line selection, firston ultrasonic backfat and then on a performance index, was supplemented over 11 generations by a process of competitive immigration, in which individuals of any breed from outside were incorporated into the line on merit. By Generation 11 the Sire Line contained genes from 9 pure breeds and 2 hybrid strains.

After a rapid initial phenotypic decline in backfat, there was little apparent response to index selection. In Generation 11, a centrally tested sample of the Sire Line showed significant improvements over contemporary Large Whites in growth rate, feed efficiency, eye-muscle area, lean percentage and some fat depths, but was significantly worse in killing-out percentage. With the exception of teat number there was no evidence of a decline in reproductive performance, to which no attention was paid during selection. Estimated heritabilities of growth rate and backfat were not sufficiently different from those reported for purebred pig populations to indicate that additive genetic variance had been changed by mixing breeds. Some of the advantages and disadvantages of the ‘open synthetic’ method of genetic improvement are discussed.

Type
Research Article
Information
Animal Production , Volume 22 , Issue 2 , April 1976 , pp. 231 - 244
Copyright
Copyright © British Society of Animal Science 1976

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Berruecos, J. M., Dillard, E. U. and Robison, O. W. 1970. Selection for low backfat thickness in swine. JAnim. Sci. 30: 844–848.Google Scholar
Cook, G. L., Smith, D. H. and Steane, D. E. 1971. The progress and penetration of the accreditation scheme in Britain 1966–1970. Proc. 10th int. Congr. Anim. Prod., Paris, 1971.Google Scholar
Falconer, D. S. 1963. Quantitative inheritance. In Methodology in Mammalian Genetics (ed. Burdette, W. J.), pp. 193–216. Holden-Day, San Francisco.Google Scholar
Fredeen, H. T. 1972. Factors influencing genetic gain. In Pig Production (ed. Cole, D. J. A.). Proc. 18th Easter School in Agricultural Science, Univ. Nottingham 1971, pp. 3–19. Butterworth, London.Google Scholar
Hill, W. G. 1971. Theoretical aspects of crossbreeding. Annls Génét. Sél. anim. 3: 23–34.CrossRefGoogle ScholarPubMed
Kempthorne, O. and Tandon, O. B. 1953. The estimation of heritability by regression of offspring on parent. Biometrics 9: 90–100.CrossRefGoogle Scholar
King, J. W. B. 1967. Pig breeding research. Proc. 9th int. Congr. Anim. Prod., Edinburgh, 1966, pp. 9–16.Google Scholar
King, J. W. B. and Roberts, R. C. 1960. Carcass length in the bacon pig; its association with vertebrae numbers and prediction from radiographs of the young pig. Anim. Prod. 2: 59–65.CrossRefGoogle Scholar
King, J. W. B. and Smith, C. 1968. Development of a pig sire line by selection, with immigration. Anim. Prod. 10: 245. (Abstr.).Google Scholar
Lopez-Fanjul, C. 1974. Selection from crossbred populations. Anim. Breed. Abstr. 42: 403–416.Google Scholar
Meat and Livestock Commission. 1972. Accreditation Scheme Yearbook 1971/72. MLC Pig Improvement Services, Bletchley, Bucks.Google Scholar
Moav, R. 1966. Specialised sire and dam lines. I. Economic evaluation of crossbreds. Anim. Prod. 8: 193–202.Google Scholar
Rempel, W. E. and El-issawi, H. F. 1959. Heritability of growth in a line of swine developed from a crossbred foundation. J. Anim. Sci. 18: 1468. (Abstr.).Google Scholar
Smith, C. 1964. The use of specialised sire and dam lines in selection for meat production. Anim. Prod. 6: 337–344.Google Scholar
Smith, C. 1966. Scientific aspects of cross-breeding. In Breeding for Pig Improvement. Proc. Pig Industry Development Authority Conf., Brighton, 1966.Google Scholar
Smith, C. and Ross, G. J. S. 1965. Genetic parameters of British Landrace bacon pigs. Anim. Prod. 7: 291–301.Google Scholar
Smith, W. C. and Lishman, W. B. 1974. A note on the comparative performance of pigs sired by Pietrain/Hampshire and Large White boars. Anim. Prod. 19: 119–122.Google Scholar
Steane, D. E. 1972. Meat and Livestock Commission breeding schemes. Proc. XIV Poultry Breeders Roundtable, Birmingham, 1972.Google Scholar
Stockhausen, C. W. F. and Boylan, W. J. 1966. Heritability and genetic correlation estimates in a new breed of swine. Can. J. Anim. Sci. 46: 211–216.Google Scholar
Strang, G. S. and King, J. W. B. 1970. Litter productivity in Large White pigs. 2. Heritability and repeatability estimates. Anim. Prod. 12: 235–243.Google Scholar
Thompson, R. 1968. Hierarchical analysis of variance program. Agricultural Research Council's Unit of Statistics, Edinburgh. (Mimeograph).Google Scholar
Ward, H. K., Rempel, W. E. and Enfield, F. D. 1964. Genetic relationship of weaning weight with post-weaning growth rate in swine. J. Anim. Sci. 23: 651–655.CrossRefGoogle Scholar
Webb, A. J. 1975. A note on the repeatability of ultrasonic backfat measurements in pigs. Anim. Prod. 20: 433–436.CrossRefGoogle Scholar
White, J. 1966. P.I.D.A.'s Accreditation Scheme. In Breeding for Pig Improvement. Proc. Pig Industry Development Authority Conf., Brighton, 1966.Google Scholar