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Variability of litter size of french sheep breeds following natural or induced ovulation

Published online by Cambridge University Press:  02 September 2010

L. Bodin  and
J. M. Elsen
L. Bodin
Affiliation:
Institut National de la Recherche Agronomique, Station dAmelioration Genetiques des Animaux, Centre de Recherches de Toulouse, BP 27, 31326 Castanet Tolosan, France
J. M. Elsen
Affiliation:
Institut National de la Recherche Agronomique, Station dAmelioration Genetiques des Animaux, Centre de Recherches de Toulouse, BP 27, 31326 Castanet Tolosan, France
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Abstract

The assumption that observed values for litter size result from a set of thresholds which impose a discontinuity to the visible expression of a continuous underlying variate has been tested using data from the French sheep recording scheme: 629 724 natural lambings for 32 different pure breeds and 66 379 litters obtained after synchronization treatment in 15 breeds. Frequencies of single, twin, triplet and higher-order births varied regularly with litter size within each fecundation type. The coefficient of variation of litter size was remarkably constant from breed to breed under both natural (0·35 to 0·40) and induced lambings for which it was higher (0·40 to 0·45). The regression of the difference between the first two thresholds of an underlying normally distributed variate on prolificacy was slowly negative for natural fecundation, but not significant for induced fecundation. A significant effect of fecundation type was found, resulting in a lower incidence of induced than of natural twin litters for the same level of prolificacy. Multivariate polynomial regression of frequencies on natural and induced prolificacy was used to predict expected frequencies of litter size and the proportion of lambs of each birth type.

Type
Papers
Information
Animal Production , Volume 48 , Issue 3 , June 1989 , pp. 535 - 541
Copyright
Copyright © British Society of Animal Science 1989

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References

REFERENCES

Anderson, T. W. 1958. An Introduction to Multivariate Statistical Analysis. John Wiley, New York.Google Scholar
Bodin, L. 1979. [Estimation of genetic parameters of the Lacaune ewe lamb litter size after fecundation on natural or induced oestrus.] Annales de Genetiques et de Selection Animale 11: 413–424.Google Scholar
Bradford, G. E. 1985. Selection for litter size. In Genetics of Reproduction in Sheep (ed. Land, R. B. and Robinson, D. W.), pp. 3–18. Butterworths, London.CrossRefGoogle Scholar
Falconer, D. S. 1960. Introduction to Quantitative Genetics. Oliver and Boyd, London.Google Scholar
Gianola, D. and Foulley, J. L. 1983. Sire evaluation for ordered categorical data with a threshold model. Génétique Selection Évolution 15: 201–224.CrossRefGoogle ScholarPubMed
Goot, H. 1973. Finnsheep in Finland. Bet Dagan, Israel, Agricultural Research Organization, The Volcani Center, Special Publication No. 28.Google Scholar
Lajous, D. 1987. [Measurement of ovulation rate and embryo mortality of the Romanov ewe. Use and interest of coelioscopy]. Thése de Recherches Universitaires, Institut National Polytechnique de Toulouse.Google Scholar
Maijala, K. 1967. Causes of variation in litter size of Finn-sheep ewes. Suomen Maatalonstieteellisen Seuran Julkaisuja 109: 136–143.Google Scholar
Ricordeau, G. 1988. [Components of numerical productivity of ewes. Use of prolific breeds.] Proceedings of the 3rd World Congress on Reproduction and Selection of Sheep and Beef Cattle, Paris, Vol. 2, pp. 567–588.Google Scholar
Ricordeau, G., Razungles, J. and Lajous, D. 1982. Heritability of ovulation rate and level of embryonic losses in Romanov breed. Proceedings of the 2nd World Congress of Genetics Applied to Livestock Production, Madrid, Vol. 7, pp. 591–595. Editorial Garsi.Google Scholar
Steine, T. 1985. Genetic studies of reproduction in Norwegian sheep. In Genetics of Reproduction in Sheep (ed. Land, R. B. and Robinson, D. W.), pp. 47–54. Butterworths, London.CrossRefGoogle Scholar