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A Comparison of Methods to Convert Foreign Progeny Test Evaluations to Approximate United Kingdom Improved Contemporary Comparison Equivalents (Friesian/Holstein)

Published online by Cambridge University Press:  22 November 2017

G.J.T. Swanson ,
H. Joanne Bellamy  and
G. Oliver
G.J.T. Swanson
Affiliation:
Milk Marketing Board, Thames Ditton, Surrey, KT7 0EL
H. Joanne Bellamy
Affiliation:
Milk Marketing Board, Thames Ditton, Surrey, KT7 0EL
G. Oliver
Affiliation:
Milk Marketing Board, Thames Ditton, Surrey, KT7 0EL
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Extract

A major problem facing breeders interested in using bulls from other populations is that the foreign bull evaluations cannot be directly compared with the evaluations produced in the United Kingdom (UK). This is due to differences in the units of measurement, the base against which all bulls are compared and the method used to express the merit of the bulls. In order that selection is possible on an equal basis, it is necessary to be able to convert bull evaluations from the scale used in the country of export to that used in the importing country.

The general formula used to convert evaluations is of the form Y = a + bX where Y is the converted evaluation, X is the evaluation in the exporting country, a is the difference between the bases used for bull evaluations and b is the factor to take account of the differences in scale.

Type
Dairy Cow
Information
Proceedings of the British Society of Animal Production (1972) , Volume 1988 , March 1988 , pp. 112
Copyright
Copyright © The British Society of Animal Production 1988

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References

Philipsson, J., Danell, B., Schaeffer, L. R. , Schneeberger, M. , Schulte-Coerne, H., and Wilmink, J.B.M. 1986. Procedures for international comparisons of dairy sires - current practice and evaluation of methods. International Bull Evaluation Service. Bull. No. 1.Google Scholar
Swanson, G.J.T. 1984. Conversions of Bull Evaluations from several countries to United Kingdom Improved Contemporary Comparison Equivalents. In Progeny Testing Methods in Dairy Cattle. IDF/EAAP Symposium, Prague. Document 183.Google Scholar