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Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350
1 Corresponding author: rex.powell{at}ars.usda.gov
International Bull Evaluation Service evaluations from May
2005 were examined for country bias by comparing Holstein
full-brother families. Countries with 
25 bulls in multicountry
full-brother families were included. The model fit evaluations of US
estimated breeding values (EBV) by absorbing full-brother family and
producing solutions for country of brothers. For yield and somatic
cell score, 24,611 and 22,802 bulls, respectively, were included
in the analysis. The study was repeated fitting evaluations on
the scales of 9 countries other than the United States. On all
countries’ scales, bulls from Australia, Germany, Great Britain, and
Japan had greater EBV for milk yield than did their full brothers
from the United States; Italian bulls had lower EBV. Bulls from
Australia, Great Britain, and South Africa had an advantage in EBV
for fat yield. For EBV for protein yield, bulls from Germany, Great
Britain, Japan, and South Africa had an advantage, whereas bulls from
the Netherlands were disadvantaged. For somatic cell score, US bulls
were advantaged compared with bulls from South Africa. Significance
and rankings of apparent biases were similar across country scales of
the international evaluations. Causes of those differences are
unknown; differences in incorporation of parental data in national
and International Bull Evaluation Service evaluations are a
possibility.
Key Words: genetic evaluation • International Bull Evaluation Service • genetic correlation
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