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Genetic improvement of litter size in pigs

Published online by Cambridge University Press:  02 September 2010

E. Avalos  and
C. Smith
E. Avalos
Affiliation:
AFRC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
C. Smith
Affiliation:
AFRC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
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Abstract

Despite the low heritability (0·1) for litter size in pigs, quite high rates of genetic improvement are predicted theoretically using conventional selection methods. The highest rates are predicted from schemes with rapid generation turnover (1 year) and with selection of both males and females at breeding age on a family selection index. This index would combine litter records (two on each relative) of the dam, her full sibs and half sibs, and of the sire's dam and his full sibs and half sibs. Annual rates of genetic change of up to half a pig per litter (a proportion 0-05 of the mean) are predicted. This rate is substantially greater than the proportional rates of genetic change possible for growth and carcass traits. These predictions are fairly insensitive to maternal and rearing environmental effects which may affect litter performance. High response rates are also predicted from two-stage selection of males, first on family index as before and then on progeny test of daughters in a large artificial insemination bred population. Intense screening in a large population for females with high litter records (hyperprolific females) can be an effective way to start an improvement programme for litter size. However, continuous screening of hyperprolific females is less effective because of the long time taken to generate enough descendants needed for the next round of intense selection. Despite the high rate of genetic change possible for litter size, omission of the trait from an index which includes growth and carcass traits would result in only small losses (proportionally less than 0·05) in economic improvement of general purpose stocks under United Kingdom market conditions. However, the losses would be higher (proportionally 0·10 to 0·18) in specialized dam stocks and inclusion of litter size in an index when selecting such stocks would be worthwhile.

Type
Research Article
Information
Animal Production , Volume 44 , Issue 1 , February 1987 , pp. 153 - 163
Copyright
Copyright © British Society of Animal Science 1987

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References

REFERENCES

Alsing, I., Krippl, J. and Pirchner, F. 1980. Maternal effects on the heritability of litter traits of pigs. Zeitschrift für Tierzuchtung und Züchtungsbiologie 97: 241–249.CrossRefGoogle Scholar
Avalos, E. 1985. Estimation of genetic parameters and responses in selection for litter size in pigs. Ph.D. Thesis, Edinburgh University.Google Scholar
Bereskin, B. 1984. Genetic correlations of pig performance and sow productivity traits. Journal of Animal Science 59: 1477–1487.CrossRefGoogle ScholarPubMed
Bichard, M. 1983. Sow productivity at the commercial level. 34th Annual Meeting of the European Association of Animal Production, Madrid. Vol. II Summaries, pp. 718–719.Google Scholar
Bolet, G. and Legault, C. 1982. [New aspects of genetic improvement of prolificacy in pigs.] Proceedings of 2nd World Congress on Genetics Applied to Livestock Production Vol. 5, pp. 548–567. Editorial Garsi, Madrid.Google Scholar
Bolet, G., Tartar, M., Laloe, D. and Felginfs, C. 1984. Theoretical efficacy of selection for prolificacy in pigs. Journées de la Recherche Porcine en France 16: 475–480.Google Scholar
Bulmer, M. G. 1971. The effect of selection on genetic variability. American Naturalist 105: 201–211.CrossRefGoogle Scholar
Burrows, P. M. 1984. Inbreeding under selection from unrelated families. Biometrics 40: 357–366.CrossRefGoogle Scholar
Clarke, P. K. and Smith, C. 1979. The value of litter size as an objective. Proceedings of the European Pig Testing Conference, Harrogate.Google Scholar
Cook, G. 1977. 1976 pig selection index revision. Paper, Meal and Livestock Commission, No. 1177. (Mimeograph).Google Scholar
Cunningham, P. J., England, M. E., Young, L. D. and Zimmerman, D. R. 1979. Selection for ovulation rate in swine. Correlated response in litter size and weight. Journal of Animal Science 48: 509–516.CrossRefGoogle ScholarPubMed
Falconer, D. S. 1981. Introduction to Quantitative Genetics. 2nd ed. Longman, London.Google Scholar
Hetzer, H. O. and Miller, R. H. 1970. Influence of selection for high and low fatness on reproductive performance of swine. Journal of Animal Science 30: 481–495.CrossRefGoogle Scholar
Hill, W. G. and Webb, A. J. 1982. Genetics of reproduction in the pig. In Control of Pig Reproduction (ed. Cole, D. J. A. and Foxcroft, G. R.), pp. 541–564. Butterworths, London.CrossRefGoogle Scholar
Hubbard, D. D. 1981. Guidelines for uniform swine improvement programs. United States Department of Agriculture, Science Education Administration, Program Aid 1157.Google Scholar
James, J. W. 1977. Open nucleus breeding systems. Animal Production 24: 287–305.Google Scholar
Johansson, K. and Kennedy, B. W. 1985. Estimation of genetic parameters for reproductive traits in pigs. Ada Agriculturae Scandinavica 35: 421–431.CrossRefGoogle Scholar
Legault, C. and Gruand, J. 1976. [Improvement of prolificacy of sows by the formation of a hyperprolific line and its use in artificial insemination.] Journées de la Recherche Porcine en France 8: 201–206.Google Scholar
Leukkunhn, A. 1984. Progeny testing of AI boars on the basis of their daughters' farrowing results. Ada Agriculturae Scandinavica 34: 300–312.CrossRefGoogle Scholar
Morris, C. A. 1975. Genetic relationships of reproduction with growth and with carcass traits in British pigs. Animal Production 20: 31–44.Google Scholar
Nelson, R. E. and Robison, O. W. 1976. Effects of postnatal maternal environment on reproduction of gilts. Journal of Animal Science 43: 71–77.CrossRefGoogle ScholarPubMed
Ollivihr, L. 1974. Optimum replacement rates in animal breeding. Animal Production 19: 257–271.Google Scholar
Ollivier, L. and Bolet, G. 1981. [Selection for litter size in the pig: results of a 10 generation selection experiment.] Journées de la Recherche Porcine en France 13: 261–267.Google Scholar
Revelle, T. J. and Robison, O. W. 1973. An explanation for the low heritability of litter size in swine. Journal of Animal Science 37: 668–675.CrossRefGoogle Scholar
Rutledge, J. J. 1980. Fraternity size and swine reproduction. 1. Effect on fecundity of gilts. Journal of Animal Science 51: 868–870.CrossRefGoogle Scholar
Skjervold, H. 1977. What about the genetic improvement in litter size. Acta Agriculturae Scandinavica, Suppl. 21, pp. 176–184.Google Scholar
Smith, C. 1964. The use of specialised sire and dam lines in selection for meat production. Animal Production 6: 337–344.Google Scholar
Smith, C. 1983. Effects of changes in economic weights on the efficiency of index selection. Journal of Animal Science 56: 1057–1064.CrossRefGoogle Scholar
Smith, C. 1984. Rates of genetic improvement in farm livestock. Research and Development in Agriculture 1: 79–85.Google Scholar
Smith, C., Dickerson, G. E., Tess, M. W. and Bennett, G. L. 1983. Expected relative responses to selection for alternative measures of life cycle economic efficiency of pork production. Journal of Animal Science 56: 1306–1314.CrossRefGoogle ScholarPubMed
Strang, G. S. and Smith, C. 1979. A note on the heritability of litter traits in pigs. Animal Production 8: 403–406.Google Scholar
Tomes, G. J. and Nielson, H. E. 1983. Increasing pig reproductive efficiency. Proceedings of 4th World Conference on Animal Production, Vol. 2, pp. 153–154. Japanese Society of Zootechnical Science, Tokyo.Google Scholar
Van Der Steen, H. A. M. 1983. Maternal and genetic influences on production and reproduction traits in pigs. Doctoral thesis, Agricultural University, Wageningen, Netherlands.Google Scholar
Vangen, O. 1980. Studies on a two trait selection experiment in pigs. VI. Heritability estimates of reproductive traits. Influence of maternal effects. Acta Agriculturae Scandinavica 30: 320–326.CrossRefGoogle Scholar