TAILIEUCHUNG - Báo cáo sinh học: "Data transformation for rank reduction in multi-trait MACE model for international bull comparison"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Data transformation for rank reduction in multi-trait MACE model for international bull comparison | Genet. Sel. Evol. 40 2008 295-308 INRA EDP Sciences 2008 DOI gse 2008004 Available online at Original article Data transformation for rank reduction in multi-trait MACE model for international bull comparison Joaquim TARRES1 2 Zengting Liu1 Vincent DUCROCQ2 Friedrich Reinhardt1 Reinhard REENTS1 1 VIT Heideweg 1 29283 Verden Germany 2 UR337 Station de génétique quantitative et appliquée INRA 78352 Jouy-en-Josas Cedex France Received 19 March 2007 accepted 5 November 2007 Abstract - Since many countries use multiple lactation random regression test day models in national evaluations for milk production traits a random regression multiple across-country evaluation MACE model permitting a variable number of correlated traits per country should be used in international dairy evaluations. In order to reduce the number of within country traits for international comparison three different MACE models were implemented based on German daughter yield deviation data and compared to the random regression MACE. The multiple lactation MACE model analysed daughter yield deviations on a lactation basis reducing the rank from nine random regression coefficients to three lactations. The lactation breeding values were very accurate for old bulls but not for the youngest bulls with daughters with short lactations. The other two models applied principal component analysis as the dimension reduction technique one based on eigenvalues of a genetic correlation matrix and the other on eigenvalues of a combined lactation matrix. The first one showed that German data can be transformed from nine traits to five eigenfunctions without losing much accuracy in any of the estimated random regression coefficients. The second one allowed performing rank reductions to three eigenfunctions without having the problem of young bulls with daughters with short lactations. rank reduction principal components genetic correlation matrix multiple across country evaluation dairy .

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