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Measures of Fertility: Heritabilities and Genetic Correlations. Paul VanRaden, Duane Norman, and Bob Miller Animal Improvement Programs Laboratory ARS, USDA, Beltsville, MD 20705-2350 paul@aipl.arsusda.gov. Analysis of Fertility Data.
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Measures of Fertility:Heritabilities and Genetic Correlations Paul VanRaden, Duane Norman, and Bob Miller Animal Improvement Programs Laboratory ARS, USDA, Beltsville, MD 20705-2350 paul@aipl.arsusda.gov
Analysis of Fertility Data • Individual breeding (ERCR) data from 2,195,643 Holstein and 145,976 Jersey lactations initiated 1998 – 2000 • 3447 Holstein sires and 3440 mating bulls • Cow and bull fertility evaluated separately • Multi-trait REML sire model
Bull Fertility Analysis • Proportion of phenotypic variance was .5% for Holstein bulls, 1.2% for Jersey bulls • Correlation of REML solutions with ERCR .71 for 446 bulls with > 300 services .83 for 212 bulls with > 1000 services .88 for 93 bulls with > 5000 services • Age of bull and country effects were removed, but could be included in solutions
Reporting of Cow Fertility • Reverse scale so positive is better? • Set mean = 100 like some Europeans? • Possible names and abbreviations • DO Days Open • DP Days Pregnant • CF Cow Fertility • DF Daughter Fertility • R Reproduction
Conclusions • Days to last breeding were most correlated genetically with days to first breeding (.85) • Non-return rate and number of services were less correlated because of lower heritabilities • Estimates similar to Weigel and Rekaya (2000) • Estimated variance for Holstein bull fertility agrees with value used in ERCR evaluation since May 2000