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Abstr. 31

WBFA. SCR. ERCR. Comparison of service-sire fertility evaluations formerly or currently available to the US dairy industry. Abstr. 31. Former and current methods. Estimated relative conception rate – ERCR 1986 (Dairy Records Management Systems) Western Bull Fertility Analysis – WBFA

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Abstr. 31

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  1. WBFA SCR ERCR Comparison of service-sire fertility evaluations formerly or currently available to the US dairy industry Abstr. 31

  2. Former and current methods • Estimated relative conception rate – ERCR • 1986 (Dairy Records Management Systems) • Western Bull Fertility Analysis – WBFA • 2003 (AgriTech Analytics) • Sire conception rate – SCR • 2008 (USDA)

  3. Methodology differences • ERCR • 70-d nonreturn rate • Minimum of 300 matings/bull for release • Included only first services for Holsteins and Jerseys • WBFA • Bull conception rate based on confirmed pregnancies • Minimum of 10 matings/bull in 10 herds • Includes services 1 through 5 for Holsteins and Jerseys • SCR • 10 effects to predict bull conception rate • Minimum matings/bull during last 4 yr • 300 for Holsteins; 100 or 200 for other breeds • Includes services 1 through 7 for all US breeds

  4. SCR bull variables • Inbreeding • Service sire • Embryo • Bull age • AI organization combined with mating year • Bull

  5. Data • Holstein and Jersey bulls • January and April 2009 evaluations from same herds • Processing centers • Agritech Analytics (ERCR, WBFA, SCR) • AgSource (ERCR, SCR) • DRMS (ERCR, SCR)

  6. Number of bulls

  7. Mean number of matings/bull

  8. Means ± SD

  9. Number of bulls by age – April 2009

  10. Means by bull age – April 2009

  11. SD by bull age – April 2009

  12. Correlations between methods*

  13. Correlations – January/April evaluations

  14. Change between evaluations

  15. Conclusions • SCR evaluations available for over twice as many bulls as ERCR and WBFA • SD of Holstein SCR (2.4) slightly higher than SD of ERCR and WBFA (1.9 to 2.0) • Holstein correlations of SCR with ERCR (0.7) and WBFA (0.6) higher than correlation of ERCR with WBFA (0.5) • Higher correlations between consecutive evaluations for SCR (0.96 to 0.98) than for ERCR and WBFA (0.93 to 0.94)

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