The United States provided the most foreign sires of sons every year, as high as 86%.

Canada was second in most years.

Combined, North American contributed 56 to 97%.

The “hot bulls” syndrome is evident from the dramatic changes in country of foreign sires from one year to year.

The Netherlands had not accounted for more than 4% of foreign sires until 12% in 1999 followed by 24, 18, and dropping to 5%.

Frequency of German sires went from 1% in 2000 to 12% in 2001 while Italian sires went from 1% in 2001 to 14% in 2002.

Where sires are from may not reflect where the genes are from.

Trends in international flow of Holstein genesR.L. Powell*, J.R. Wright, and H.D. Norman

Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350

Abstr. T39

INTRODUCTION Holstein genes spread from Europe to much

of the world through live cattle more than 100 yr ago.

By the advent of artificial insemination, selection emphasis in North America had led to a specialized dairy strain that was in demand internationally.

Beginning in 1995, genetic evaluations through Interbull more accurately identified the best bulls across countries.

Many of the same bulls were used in several countries, particularly to sire sons for progeny testing, therefore an increasing number of countries had bulls worthy of international consideration.

OBJECTIVE This study documents the changes in the

source of Holstein sires of bulls.

DATA & METHODS

Data from over 100,000 Holstein bulls from 27 countries in the April 2009 Interbull evaluation.

Bull birth years were from 1986 to 2003.

CONCLUSIONS Sourcing of sires is a dynamic situation with

the proportion of sires from a given country rapidly changing.

Across countries, the majority of Holstein bulls progeny tested have a foreign sire and percentage has been consistent across years.

While trends are not steady, especially in recent years, there is a tendency for more US bulls to have foreign sires and for non-North American bulls to have fewer foreign sires.

This study addressed only the frequency of foreign sires over years and not the relative improvement in quality that may have occurred.

Portion of bulls with a foreign sire (all countries)

Percentage of bulls having a foreign sire was steady (56% in 1986 and 55% in 2003).

Highest percentage was 65% for 1995 to 1997.

RESULTS

Through 1991, nearly all AI bulls progeny tested in France, Germany, Italy, and The Netherlands were sired by bulls from other countries.

For bulls from those countries born in 2003, 51 to 88% were by foreign sires.

Although the United States used fewer foreign sires of sons, that portion has been about 25% for bulls born this decade.

RESULTS (cont.) RESULTS (cont.)

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Paternal grandsires of bulls having a foreign sire were even more dominated by North America (98-99%, except for 1999).

http://aipl.arsusda.gov/

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