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**Location: Animal Improvement Programs**
**2005 Annual Report**
**4d.Progress report.**													This report serves to document research conducted under a trust agreement between ARS and the National Association of Animal Breeders (Columbia, MO), which is scheduled to terminate on March 31, 2010. This project replaced project 1265-31000-085-02T " Increasing Accuracy of Genetic Evaluations for Calving Ease," which expired on November 30, 2004. Additional details of research can be found in the report for the parent project 1265-31000-085-00D "Improving Genetic Prediction of Economic Merit of Dairy Animals"; research conducted under the agreement is related to objective 4 (improved rankings for overall genetic merit) of the parent project. Distribution of calving ease scores within herd-year was investigated, and some herds were found to have extremely unusual distributions. A goodness-of-fit criterion was developed that identified approximately equal portions of records in abnormal distributions across herd size. Preliminary research showed that number of bulls with unusual evaluations or large changes between evaluations is reduced by excluding herd-years with abnormal distributions. A two-level criterion was developed to minimize year-to-year change in rejection of data. Work is continuing on determination of which level of exclusion provides the greatest benefit. Genetic evaluations of calving ease for over 44,000 dairy bulls were distributed through the National Association of Animal Breeders to the dairy industry in February, May, and August 2005 for use in mating decisions and selection decisions; distribution was increased from semiannual to quarterly in May 2005 after the International Bull Evaluation Service (Uppsala, Sweden) began routine quarterly release of international calving-ease evaluations for Holstein bulls in February 2005. Feasibility of implementing routine national calving-ease genetic evaluations was examined for Brown Swiss and Jersey sires that include records of crossbred calvings. Evaluations were calculated for each breed using only purebred calvings and both purebred and crossbred calvings. In the latter evaluation, the sire-maternal grandsire model used for the routine evaluation of Holstein calving ease was modified to include a fixed breed composition effect to account for differences between purebred and crossbred calvings. Jersey cows were found to have little calving difficulty (.5 to .7%), and the range of Jersey bull evaluations was limited, which indicated that routine evaluation of Jerseys for calving ease would be of little value. Results from the Brown Swiss evaluation indicated that a routine evaluation would provide Brown Swiss breeders with a useful tool for genetic improvement. Further examination of data showed that many Brown Swiss calvings were in mixed herds with Holstein calvings. Therefore, a joint evaluation for Brown Swiss and Holstein bulls was developed. Brown Swiss data showed genetic variability similar to that of Holsteins, which indicated that implementation of a routine evaluation that included Brown Swiss calving ease would be of value. Brown Swiss bulls appeared to produce daughters with superior maternal calving ability compared with Holsteins. Validation of the joint evaluation was performed by comparing results with routine Holstein evaluations. Holstein solutions from the joint evaluation were comparable with results from routine Holstein evaluations. Correlations among solutions and evaluations showed that Holstein evaluations were not adversely affected by Brown Swiss data; however, Brown Swiss  sires were reranked as compared with Brown Swiss-only evaluation. National calving ease evaluations were extended to accommodate joint evaluation of Brown Swiss and Holstein bulls using records from purebred and crossbred calvings, and routine national evaluations for Brown Swiss bulls began in February 2005.						
    Project TeamNorman, H  - *Duane*Wiggans, George  
Project Annual Reports FY 2008 FY 2007 FY 2006 FY 2005 
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