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The article explores the transition from National EBVs to Global GEBVs in livestock breeding using Genomic MACE. Single Sire Examples and Brown Swiss Data are analyzed to assess reliability and potential future implications.
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Development of GenomicGMACE Pete Sullivan, CDN & Paul VanRaden*, USDA
Introduction • Genomics is here now • National EBVs are being replaced by GEBVs • GEBVs may not be strictly national • Countries may share data, or use MACE • Genetic tests may be repeated (DGAT), shared or sold among countries
Introduction • MACE assumption: • National data sets are independent, i.e. separate recorded cow populations • Sire with EBV from 100 daughters in 3 countries has 300 daughters in total • Genomics: • Sire can have GEBV from 100 daughters in 3 countries with only 100 daughters in total • MACE must evolve to GMACE
Objectives • Overall objectives: • Update MACE model for genomic input data from participating countries • Create GMACE software for application as early as 2010 • Today: • Introduce GMACE with some examples • Preliminary results from software tests • Reactions and feedback from members
Methods De-regression MACE
Methods De-regression MACE GMACE
( = %EDC from genomics) Methods • D is a diagonal matrix • Residual variances of de-regressed proofs • E = D plus genomic covariances from shared data % common (shared) data Max correlation between genomic predictions Genomic portion of variance
Single Sire Example • GMACE for a single sire • GEBV in 3 countries (A, B, C) • EDC from genomics = 20 • No data in 4th country D • All rg = .90, h2 = .33, • as a young bull (EDC=0+20, ɣ=100%) • with 1st crop proofs in A, B and C (EDC=100+20, ɣ=17%)
Brown Swiss Data- 9 countries • Used Pedigree and EBV from April 2009 Interbull files to simulate bull genotypes • 50,000 SNP and 10,000 QTL • VanRaden (2009) • 8073 proven bulls • 120 young bulls sampled in U.S.A. used to test genomic predictions
Brown Swiss DataYoung USA Bull Reliability • GMACE reliability very close to global genomic evaluation model • If “c” is correct • No shared data for GEBV in this study (i.e. c=0.0) • Some error in “c” seems O.K. (c=0.5 still good) • How robust is GMACE? • c=? %EDC from genomics ( =?)
GMACE – next steps • Need to test GMACE when data are shared among countries for national GEBVs (c>0) • Need to extend MACE / MT-MACE reliability approximation for GMACE • Needs multi-country progeny absorption if c>0 • May need MT-GMACE (e.g. for fertility traits) • Are national cow EBVs useful for GMACE? • Question also for MACE, but • More important for young genotyped bulls in GMACE
Conclusions • Software to extend from national to international GEBVs nearing completion • Application by Interbull in 2010? 2011? • A few developments and validation tests are still needed for the model and software • Enhancements may be added after the initial application • Extension to MT-GMACE • Model refinements
Acknowledgements • Interbull genomics task force • Georgios Banos • Mario Calus • Vincent Ducrocq • João Dϋrr • Hossein Jorjani • Esa Mäntysaari • Zengting Liu