Reference : Accounting for heterogeneous variances in multi-trait evaluation of Jersey type traits
Scientific congresses and symposiums : Paper published in a journal
Life sciences : Animal production & animal husbandry
Life sciences : Genetics & genetic processes
http://hdl.handle.net/2268/23047
Accounting for heterogeneous variances in multi-trait evaluation of Jersey type traits
English
Gengler, Nicolas [Université de Liège - ULiège > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]
Wiggans, G. R. [> > > >]
Thornton, L. [> > > >]
Wright, J. [> >]
Druet, Tom [Université de Liège - ULiège > Département des productions animales (DPA) > GIGA-R : Génomique animale >]
Jul-2005
Journal of Dairy Science
American Dairy Science Association
83/88
Suppl. 1/ Suppl. 1
J. Anim. Sci. Vol. 83, Suppl. 1/J. Dairy Sci. Vol. 88, Suppl. 1
11
Yes (verified by ORBi)
International
0022-0302
1525-3198
Champaign
IL
JAM Joint Animal Meeting 2005
July 24-28, 2005
ADSA - PSA - AMPA - CSAS - ASAS
Cincinnati, Ohio
USA
[en] heterogeneous variance adjustment ; type evaluation
[en] The multi-trait genetic evaluation system for type traits was modified to estimate adjustments for heterogeneous variance (HV) simultaneously with estimated breeding values (EBV) for final score and 14 linear traits. Heterogeneity, estimated for transformed traits, was regressed within parity toward the population variance means by fitting a model with fixed effects of mean final score forherd, size of contemporary group, appraisal month, and appraisal year-season and a random effect for interaction between herd and appraisal date. Method R was used to estimate variances for the heterogeneity model in each EBV iteration. Data was from the 766,725 appraisals included in the official November 2004 evaluation. Parent averages were calculated from evaluations with recent appraisals removed. Annual trends for cow EBV were lower with HV adjustment than for unadjusted EBV for all traits. The SD of Mendelian sampling (evaluation minus mean of parent evaluations) declined less over time for HV adjusted than for unadjusted evaluations. The slope at year 2000 of Mendeliansampling SD from HV adjusted evaluations was only 22% for udder depth to 48% for teat length of the slope of that for unadjusted evaluations. This adjustment for HV was implemented in May 2001 and should make selection decisions more accurate by using these proposed integrated HV adjustments.
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/23047
http://www.jtmtg.org/JAM/2005/abstracts/toc.htm

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