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![](https://webarchive.library.unt.edu/eot2008/20090512171012im_/http://www.ars.usda.gov/incme/images/Research_head.gif) |
Research Project:
Development and Enhancement of Genetic Evaluations for Calving Traits
Location: Animal Improvement Programs
2008 Annual Report
1a.Objectives (from AD-416)
Calculate and improve the national evaluation for calving ease and contribute to improved international evaluation of calving traits through cooperation with Interbull. Improve the quality of the reporting of calving ease data and investigate evaluations for stillbirth.
1b.Approach (from AD-416)
Evaluations will be calculated semi-annually; procedures to improve evaluations by excluding herds with abnormal distributions of calving ease scores will be investigated. Ways to account for skewness in international evaluations will be developed for use by Interbull. Data quality will be improved by identifying herds with reporting problems for field staff and using within-herd identification to improve matching of data with existing pedigrees. Data on stillbirths will be requested.
3.Progress Report
A linear model with first and later parities as separate traits was applied separately for calving ease and stillbirth for the test evaluation of the International Bull Evaluation Service (Interbull; Uppsala, Sweden), and trend validation tests were conducted. Considerably lower correlations of U.S. first-parity calving ease and stillbirth evaluations with evaluations from other countries compared with previous correlations from the all-parity threshold model indicates a need for additional research to determine if the change is caused by a model problem or is the consequence of reporting only first-parity traits. If the low correlation can be explained by reporting of only first-parity results, then an index of first- and later-parity traits may be justified to improve the correlation. A high correlation is desirable because it allows more information to be shared between countries for the calving traits. Triannual genetic evaluations of over 47,000 Holstein bulls for calving ease and stillbirth and of approximately 850 Brown Swiss bulls for calving ease were calculated and distributed through the National Association of Animal Breeders to the dairy industry in January, April, and August 2008. Monitoring activities for the project included frequent e-mail and phone contact between the Animal Improvement Programs Laboratory (AIPL) and the Cooperator about semiannual data exchange and resolution of data quality issues. Representatives of Cooperator member organizations work directly with AIPL scientists to resolve questions about evaluations of individual bulls. Members of the AIPL scientific and information technology staff attended meetings of the Cooperator's Dairy Sire Evaluation Committee at which proposed changes are discussed and feedback is given.
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Last Modified: 05/12/2009
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