Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Dairy Sci. 2002 Jul;85(7):1863-8.

International dairy bull evaluations expressed on national, subglobal, and global scales.

Author information

  • 1Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705-2350, USA. rpowell@aipl.arsusda.gov

Abstract

Genetic evaluations on a global scale were calculated for Holstein bulls using the May 2001 International Bull Evaluation Service (Interbull) evaluations expressed on each of 27 national scales. National scale data were weighted by the country's proportion of total daughters from all bulls (population size) to represent market share. Correlations between Interbull evaluations on national scales and evaluations on a global scale ranged from 0.961 to 0.998 (mean of 0.988). Number of top 100 bulls for protein yield that were in common between national and global scales ranged from 54 to 94 and was related significantly to mean genetic correlation between a country and the other 26 countries. Weighting of evaluations on national scales by population size, inverse of population size weight, or equal weight produced practically the same group of top bulls and correlations among the three global scales were 0.999. Thus, the method for combining Interbull evaluations expressed on national scales had only minor impact and was much less important than use of all data. Subglobal scales were established by a clustering technique that gave two to five groups. For grazing countries or other atypical systems, a subglobal scale may provide better guidance, although a scale representing three grazing countries did not provide the expected improvement over a global scale in the relationship with the three country scales. If conditions in non-participating countries are generally represented by participating countries, most needs are met by a global scale.

PMID:
12201537
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk