August 25, 1999 |
Changes in USDA-DHIA Genetic Evaluations (August 1999)H.D. Norman, Research Leader, AIPL |
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August 25, 1999 |
Changes in USDA-DHIA Genetic Evaluations (August 1999)H.D. Norman, Research Leader, AIPL |
This memorandum is to inform you that several changes that the Animal Improvement Programs (AIPL) expected to implement for February 2000 genetic evaluations will not be made at that time. At present, AIPL has not been able to obtain and to review sufficiently the test-day model results that are needed for U.S. test-day evaluations to be included in the Interbull test evaluation that is due on September 1, 1999. The results from the new test-day procedure differ somewhat from what was expected, particularly in regard to genetic trend, and I believe that further analysis would be beneficial.
The Council on Dairy Cattle Breeding has encouraged AIPL to bundle changes so that the industry does not have to cope with large differences in predicted transmitting abilities with each quarterly evaluation. The Council also has encouraged AIPL to provide more complete information on the impact of planned changes. At present, I do not feel that AIPL could determine that impact for test-day evaluations.
The base change scheduled for year 2000 and other planned changes, such as improved economic indexes, also will be delayed until the test-day model can be implemented. Several industry groups have communicated to AIPL during the last year that they preferred that the base change be made in conjunction with other planned changes.
Because Interbull allows only one test evaluation every 6 months, AIPL will be submitting test evaluations by September 1 that have been adjusted for inbreeding. Those test evaluations will assist AIPL researchers in determining the impact that an inbreeding adjustment would have on national evaluations. However, an inbreeding adjustment will not be implemented for February 2000 evaluations.
The changes that were targeted for February 2000 will be implemented for August 2000 evaluations. I apologize for any inconvenience that these scheduling revisions may cause.