|Muir, W - PURDUE UNIVERSITY|
|Cheng, Heng Wei|
Submitted to: Poultry Science Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 17, 2003
Publication Date: N/A
Technical Abstract: Over the past five decades the art of animal breeding has rapidly advanced into an exacting science including such advanced tools as Best Linear Unbiased Prediction (BLUP) and REML estimation of variance components. Unfortunately in most selection programs only traits directly related to productivity are considered, as a result, those breeding programs ignore traits that impact animal welfare. Consequences of ignoring animal welfare in breeding programs are three fold: 1)if higher producing animals tend to be more competitive, then the effect of selection is to increase competition, which worsens the animal's welfare; 2)increased competition has the effect of lowering productivity of other animals that are in direct contention, thus resulting in reduced (or negative) gains for productivity; and 3)genotype-genotype interactions (competition) invalidate the traditional BLUP animal model and negate many advantages of this technology and could in fact make it a liability. This paper reviews recent advances that allow selection on production traits but takes into account competitive interactions. Those advances fall into two categories: 1) group selection and 2) advanced mixed models with a second random effect for indirect genetic effects (competition). Both methods have been verified in poultry breeding applications and have resulted in dramatic improvements in livability, productivity, and welfare.