HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pollak, E. J. Articles by Quaas, R. L. Search for Related Content PubMed Articles by Pollak, E. J. Articles by Quaas, R. L.

Definition of Group Effects in Sire Evaluation Models

Department of Animal Science, Cornell University, Ithaca, NY 14853

ABSTRACT

Group effects are used in sire evaluation models to account for genetic trend. The objective of this paper was to develop definitions of these group effects where sires are related. Definitions were obtained for sire groups from results of a set of modified mixed model equations. Definitions were functions of genetic selection differentials. Definitions were dependent on the matrix of numerator relationships.

Simulation of 10,000 replicates of a particular population structure was used to evaluate definitions. Three models with different relationship matrices were fit to the data for each replicate. Group solutions were compared to hypothesized group effects computed from realized genetic selection differentials in each replicate. There was close agreement between group solutions and corresponding hypothesized effects.