International genomic evaluation methods for dairy cattle

Genetics Selection Evolution

Research

Paul M VanRaden¹  Peter G Sullivan² 

[1] Animal Improvement Programs Laboratory, USDA, Building 5 BARC-West, 20705-2350, Beltsville, MD, USA;Canadian Dairy Network, 660 Speedvale Ave. West, Suite 102, N1K 1E5, Guelph, Ontario, Canada;

关键词: Genetic Correlation;    Genomic Prediction;    Genomic Evaluation;    Residual Correlation;    Estimate Breeding Value;   

DOI  :  10.1186/1297-9686-42-7

 received in 2009-09-24, accepted in 2010-03-01,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundGenomic evaluations are rapidly replacing traditional evaluation systems used for dairy cattle selection. Higher reliabilities from larger genotype files promote cooperation across country borders. Genomic information can be exchanged across countries using simple conversion equations, by modifying multi-trait across-country evaluation (MACE) to account for correlated residuals originating from the use of foreign evaluations, or by multi-trait analysis of genotypes for countries that use the same reference animals.MethodsTraditional MACE assumes independent residuals because each daughter is measured in only one country. Genomic MACE could account for residual correlations using daughter equivalents from genomic data as a fraction of the total in each country and proportions of bulls shared. MACE methods developed to combine separate within-country genomic evaluations were compared to direct, multi-country analysis of combined genotypes using simulated genomic and phenotypic data for 8,193 bulls in nine countries.ResultsReliabilities for young bulls were much higher for across-country than within-country genomic evaluations as measured by squared correlations of estimated with true breeding values. Gains in reliability from genomic MACE were similar to those of multi-trait evaluation of genotypes but required less computation. Sharing of reference genotypes among countries created large residual correlations, especially for young bulls, that are accounted for in genomic MACE.ConclusionsInternational genomic evaluations can be computed either by modifying MACE to account for residual correlations across countries or by multi-trait evaluation of combined genotype files. The gains in reliability justify the increased computation but require more cooperation than in previous breeding programs.

【 授权许可】

CC BY   
© VanRaden and Sullivan; licensee BioMed Central Ltd. 2010