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Research Project: Improving Genetic Prediction of Economic Merit of Dairy Animals

Location: Animal Improvement Programs Laboratory

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

Author

Submitted to: Interbull Annual Meeting Proceedings
Publication Acceptance Date: May 28, 2004
Publication Date: August 1, 2004
Publisher's URL: http://www-interbull.slu.se/bulletins/bulletin32/VanRaden.pdf
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.

 
Project Team
Norman, H - Duane
Powell, Rex
Vanraden, Paul
Wiggans, George
Kuhn, Melvin
Van Tassell, Curtis - Curt

Publications

Related National Programs
  Food Animal Production (101)

Related Projects
   Increasing Accuracy of Genetic Evaluations for Calving Ease
   Improving Identification, Reproduction, and Health in Dairy Cattle
   Improving Identification, Reproduction, and Health in Dairy Cattle
   Improving Identification, Reproduction, and Health in Dairy Cattle
   Improving Reproduction and Health in Dairy Cattle Through Use of on-Farm Databases
   Improving Identification, Reproduction, and Health in Dairy Cattle
   Estimating Economic Contribution of Daughter Pregnancy Rate to Lifetime Net Merit
   Effects of Heat Stress on Reproduction, Production, and Survival of Holsteins and Jerseys Or Holsteins and Brown Swiss in the Same Herd
   Improving Fitness in Dairy Cattle by Facilitating the Initiation of a National Research Database for Health Traits
   Estimating Daily Milk, Component Yield, and Scs from Individual Milking Data
   Improving Prediction of Dairy Bull Genetic Merit Considering Heat Stress by Geographical Region
   Genetic and Environmental Parameters for Yield Traits Across Varying Herd Sizes, Production Levels and Lactation Number

 
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