Bias in genetic evaluation using random regression test-day model

The effect of an upgraded Finnish evaluation model on bias in estimated breeding values for protein yield was investigated. Evaluations based on repeatability animal model and on random regression test-day model without and with heterogeneous variance adjustment were compared. Comparisons were based...

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Main Authors: M. LIDAUER, E.A. MÄNTYSAARI
Format: Article
Language:English
Published: Scientific Agricultural Society of Finland 2008-12-01
Series:Agricultural and Food Science
Online Access:https://journal.fi/afs/article/view/5871
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author M. LIDAUER
E.A. MÄNTYSAARI
author_facet M. LIDAUER
E.A. MÄNTYSAARI
author_sort M. LIDAUER
collection DOAJ
description The effect of an upgraded Finnish evaluation model on bias in estimated breeding values for protein yield was investigated. Evaluations based on repeatability animal model and on random regression test-day model without and with heterogeneous variance adjustment were compared. Comparisons were based on the average difference between pedigree indices and the future estimated breeding values, based on own or on daughter performance records. This was defined as empirical bias. The pedigree indices were computed from reduced data sets where four years of the most recent data were excluded. Results showed an upward bias in the protein yield pedigree indices for Ayrshire young sires of 2.2 kg, 2.5 kg and 1.8 kg from the repeatability animal model, random regression test-day model and random regression test-day model with heterogeneous variance adjustment, respectively. Pedigree indices for daughters of young sires were upward biased, whereas pedigree indices for daughters of proven sires were slightly underestimated when heterogeneous variance was not accounted. Inclusion of test-day yields from the fourth lactation onwards increased the bias. Moving from repeatability animal model to random regression test-day model did not reduce the bias, whereas adjustment of heterogeneous variance reduced bias.;
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spelling doaj.art-f55c0e2952454d38b9fa5c73fd3c29ce2022-12-22T03:17:38ZengScientific Agricultural Society of FinlandAgricultural and Food Science1459-60671795-18952008-12-01162Bias in genetic evaluation using random regression test-day modelM. LIDAUERE.A. MÄNTYSAARIThe effect of an upgraded Finnish evaluation model on bias in estimated breeding values for protein yield was investigated. Evaluations based on repeatability animal model and on random regression test-day model without and with heterogeneous variance adjustment were compared. Comparisons were based on the average difference between pedigree indices and the future estimated breeding values, based on own or on daughter performance records. This was defined as empirical bias. The pedigree indices were computed from reduced data sets where four years of the most recent data were excluded. Results showed an upward bias in the protein yield pedigree indices for Ayrshire young sires of 2.2 kg, 2.5 kg and 1.8 kg from the repeatability animal model, random regression test-day model and random regression test-day model with heterogeneous variance adjustment, respectively. Pedigree indices for daughters of young sires were upward biased, whereas pedigree indices for daughters of proven sires were slightly underestimated when heterogeneous variance was not accounted. Inclusion of test-day yields from the fourth lactation onwards increased the bias. Moving from repeatability animal model to random regression test-day model did not reduce the bias, whereas adjustment of heterogeneous variance reduced bias.;https://journal.fi/afs/article/view/5871
spellingShingle M. LIDAUER
E.A. MÄNTYSAARI
Bias in genetic evaluation using random regression test-day model
Agricultural and Food Science
title Bias in genetic evaluation using random regression test-day model
title_full Bias in genetic evaluation using random regression test-day model
title_fullStr Bias in genetic evaluation using random regression test-day model
title_full_unstemmed Bias in genetic evaluation using random regression test-day model
title_short Bias in genetic evaluation using random regression test-day model
title_sort bias in genetic evaluation using random regression test day model
url https://journal.fi/afs/article/view/5871
work_keys_str_mv AT mlidauer biasingeneticevaluationusingrandomregressiontestdaymodel
AT eamantysaari biasingeneticevaluationusingrandomregressiontestdaymodel