Author
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Powell, Rex |
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Submitted to: Red Bloodlines
Publication Type: Trade Journal Publication Acceptance Date: 4/1/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Although points of view differ on the issue of frequency of genetic evaluation, there seems to be no argument that quarterly evaluations promote genetic gain. No scientific arguments support reversion to semiannual evaluation: the more current the information, the better the selection decisions. Changes in evaluations with a 3-month interval are about 70% as large as with 6-month intervals. New bulls are evaluated 3 months sooner, and bulls with evaluation decreases and increases are identified sooner. For bulls with the largest decreases from February to August 1997, the May protein evaluation almost always was closer to the August evaluation than was the February evaluation. For bulls with evaluations that changed at least 10 pounds, May evaluations were closer 98% of the time. Although the United States still has a good representation of the top 100 bulls on the scales of other countries, fewer than half of the top bulls for protein on most other countries' scales are U.S. bulls. Trends in representation in the top 100 by birth year show a decline of about 2 bulls per year on the U.S. protein scale and more on the scales of other countries. One of the obvious options that the United States can pursue to compete internationally is to calculate evaluations often to increase the speed of progeny testing. Publicly available evaluations should be more frequent than twice a year if the United States is to forestall the time when the U.S. lead in dairy genetics is overtaken. The inconvenience of estimates that are updated should not be an insurmountable barrier to genetic progress and competitiveness globally. |
