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|Title:||Comparison of Different Variance Component Estimation Approaches for MACE: Direct and Bottom-up PC||Contributor(s):||Tyriseva, A M (author); Meyer, Karin (author); Jakobsen, J (author); Ducrocq, V (author); Fikse, F (author); Lidauer, M H (author); Mantysaari, E A (author)||Publication Date:||2009||Handle Link:||https://hdl.handle.net/1959.11/5120||Abstract:||Multiple-trait across country evaluation (MACE) is used for international genetic evaluation of dairy bulls. MACE treats records in different countries as different traits. Thus, a sire will get a breeding value for each participating country. Whenever a country makes changes to their national evaluation model, the genetic variance-covariance (VCV) matrix needs to be re-estimated. Estimation of the VCV matrix is a different task. For the Holstein production evaluation, which includes 26 traits, it is not possible to estimate the VCV matrix in a single analysis with the currently available estimation methods and the given time constraints. Hence, the complete matrix is built from analyses of sub-sets. This readily results in a non-positive matrix and a bending procedure (Jorjani et al., 2003) needs to be applied to obtain a positive definite matrix. In addition, the VCV matrix is usually over-parameterized as genetic correlations between countries are generally high.||Publication Type:||Conference Publication||Conference Details:||Interbull 2009: 2009 Interbull Meeting, Barcelona, Spain, 21 - 24 August||Source of Publication:||Interbull Bulletin 40: Proceedings of the 2009 Interbull Meeting, v.40, p. 72-76||Publisher:||International Bull Evaluation Service||Place of Publication:||Uppsala, Sweden||ISSN:||1011-6079||Fields of Research (FoR) 2008:||070201 Animal Breeding||Socio-Economic Objective (SEO) 2008:||830302 Dairy Cattle||HERDC Category Description:||E2 Non-Refereed Scholarly Conference Publication||Publisher/associated links:||http://www-interbull.slu.se/bulletins/bulletin40/Tyriseva.pdf|
|Appears in Collections:||Animal Genetics and Breeding Unit (AGBU)|
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