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STATUS REPORT November 2000 CONCEPTION RATE
EVALUATIONS OF AI SIRES The NAAB Fertility Committee chaired by Dr. Kent Weigel, University of Wisconsin-Madison, has been providing input to Dr. John Clay at DRMS, Raleigh concerning various technical issues with the May 2000 Estimated Relative Conception Rate (ERCR) evaluation. Dr. Weigel had conducted collaborative research with DRMS to study methodologies to enhance the accuracy of ERCRs. To help study changes proposed for the November 2000 evaluations, Dr. Clay provided the NAAB Fertility committee three files for review. These were the original May 2000 evaluations, the May 2000 evaluations recalculated using methodology to be implemented in November 2000, and the November 2000 evaluations using the revised methodology. It was concluded, that while there are still areas for continued research and improvement of the ERCR system, there was no reason not to make the evaluations available to the industry. Dr. Weigel and the NAAB Fertility Committee will continue to cooperate with Dr. Clay in an effort to improve the ERCRs. The actual ERCRs are found on the DRMS Website (www.drms.org). The site also has documents with comments about the evaluations, recent research activities and the accuracy of ERCRs. In their comments, DRMS points out that ERCR computation procedures were developed to compare individual bulls and probably are not valuable to compare differences in AI organizations. Additionally, action was taken in 1999 by the NAAB International Marketing and Dairy Sire Evaluation Committees to recommend that ERCR data not be used for comparisons between AI organizations until there is a national evaluation system for bull fertility. DRMS is trying to achieve a national evaluation, however, not all computing centers are participating in the evaluation. Until they do, the ERCR evaluation cannot be considered a national evaluation and organizational comparisons of ERCR values should be avoided. DRMS further states that the proportion of conception rate that can be attributed to the AI service bull is small. ERCR should be a secondary trait of selection and should not be used alone to try to improve the general conception rate of the herd. To improve average conception rate within a herd, most attention should be given to improving the day-to-day reproductive management. NAAB, Dr. Weigel, and the NAAB Fertility Committee will continue to cooperate with Dr. Clay and DRMS, Raleigh, to improve the ERCR evaluations and work to achieve a national fertility evaluation.
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