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A retrospective evaluation of the weights in the cow genetic index

Published online by Cambridge University Press:  02 September 2010

Susan Brotherstone  and
W. G. Hill
Susan Brotherstone
Affiliation:
Institute of Animal Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN
W. G. Hill
Affiliation:
Institute of Animal Genetics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN
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Abstract

The fat plus protein yield of 70 011 records of pedigree British Friesian/Holstein cows was regressed on various components of their dam's Cow Genetic Index (CGI) in order to obtain the regression coefficients for comparison with the index weights currently used in the calculation of the CGI. For the first and later (2 to 5) lactation components of the CGI, the regression coefficients obtained by analysis were consistent with the tabulated index weights, but the coefficients for the sire component tended in some cases to be lower than the table values. The analysis was repeated using only dams that had widely used sires. The partial regression coefficients for the first and later lactation components were again consistent with the tabulated weights, and the coefficient for the sire component lay within one s.d. of the table values. In all cases, a cow's CGI is shown to take full account of her first and later lactation information and her sire's and dam's transmitting abilities.

Type
Research Article
Information
Animal Production , Volume 44 , Issue 3 , June 1987 , pp. 355 - 361
Copyright
Copyright © British Society of Animal Science 1987

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References

REFERENCES

Brotherstone, S. and Hill, W. G. 1986. Heterogeneity of variance amongst herds for milk production. Animal Production 42: 297–303.Google Scholar
Harvey, W. R. 1977. Users guide for LSML76 mixed model least-squares and maximum likelihood computer program. Ohio State University, Columbus.(Mimeograph).Google Scholar
Hill, W. G., Edwards, M. R., Ahmed, M.-K. A. and Thompson, R. 1983. Heritability of milk yield and composition at different levels and variability of production. Animal Production 36: 59–68.Google Scholar
Hill, W. G. and Swanson, G. J. T. 1983. A selection index for dairy cows. Animal Production 37: 313–319.Google Scholar
Maijala, K. and Hanna, M. 1974. Reliable phenotypic and genetic parameters in dairy cattle. Proceedings of the 1st World Congress on Genetics Applied to Livestock Production, Madrid, Vol. 1, pp. 541–563.Google Scholar
Meyer, K. 1984. Estimates of genetic parameters for milk and fat yield for the first three lactations in British Friesian cows. Animal Production 38: 313–322.Google Scholar
Milk Marketing Board. 1979. The improved contemporary comparison. Report of the Breeding and Production Organisation, Milk Marketing Board, No. 29, pp. 91–95.Google Scholar
Milk Marketing Board. 1982. Cow genetic index. Report of the Breeding and Production Organisation, Milk Marketing Board, No. 32, pp. 59–66.Google Scholar
Murphy, P. A., Everett, R. W. and Van Vleck, L. D. 1982. Comparison of first lactations and all lactations of dams to predict sons' milk evaluations. Journal of Dairy Science 65: 1999–2005.CrossRefGoogle ScholarPubMed
Westell, R. A. and Van Vleck, L. D. 1985. Prediction of heifer transmitting ability from genetic evaluations of sire, dam and maternal grandsire. Journal of Dairy Science 68: 1432–1437.CrossRefGoogle ScholarPubMed