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United States Department of Agriculture

Agricultural Research Service

Title: Choice of Scales for Delivery of Genetic Evaluations to the Public

Author
item Vanraden, Paul

Submitted to: Interbull Annual Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 28, 2004
Publication Date: August 1, 2004
Citation: Van Raden, P.M. 2004. Choice of scales for delivery of genetic evaluations to the public. International Bull Evaluation Service Bulletin 32:118-121.

Interpretive Summary: Genetic evaluations and selection indexes would be easier to compare if units, bases, and directions were more similar. Many customers do not understand all of the numbers regardless which of the 25 national scales is used. Trait advertising is easier if positive numbers indicate better bulls. Current national scales for udder health, longevity, conformation, and yield traits are compared in detail. None of these traits are displayed uniformly, but udder health scales are least uniform because 9 countries have higher numbers favorable whereas 10 countries have lower numbers favorable. Base changes provide an opportunity to redefine scales or traits to make genetic evaluations simpler to interpret for both domestic and foreign breeders. As recommended by Interbull, 18 of 25 countries use step-wise genetic bases which will be updated in 2005. Scale changes and base changes introduced together make sense because both changes affect mean and SD. Each country may define their own scales of expression and bases, but international marketing would be simpler with some uniformity and harmonization.

Technical Abstract: Genetic evaluations and selection indexes would be easier to compare if units, bases, and directions were more similar. Many customers do not understand all of the numbers regardless which of the 25 national scales is used. Trait advertising is easier if positive numbers indicate better bulls. Current national scales for udder health, longevity, conformation, and yield traits are compared in detail. None of these traits are displayed uniformly, but udder health scales are least uniform because 9 countries have higher numbers favorable whereas 10 countries have lower numbers favorable. Base changes provide an opportunity to redefine scales or traits to make genetic evaluations simpler to interpret for both domestic and foreign breeders. As recommended by Interbull, 18 of 25 countries use step-wise genetic bases which will be updated in 2005. Scale changes and base changes introduced together make sense because both changes affect mean and SD. Each country may define their own scales of expression and bases, but international marketing would be simpler with some uniformity and harmonization.

Last Modified: 10/21/2014
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