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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Belonsky, G. M. Articles by Kennedy, B. W. Search for Related Content PubMed PubMed Citation Articles by Belonsky, G. M. Articles by Kennedy, B. W.

Selection on Individual Phenotype and Best Linear Unbiased Predictor of Breeding Value in a Closed Swine Herd¹

University of Guelph², Guelph, Ontario, Canada NIG 2W1

Abstract

Computer simulation of a closed 100-sow and 4-boar swine herd was used to analyze effects of selection method on genetic change, inbreeding and genetic variance over 10 yr for traits with heritabilities (h²) of .10, .30 and .60. Selection of replacement animals was either on individual phenotype or best linear unbiased predictor (BLUP) of breeding value using an animal model. For both methods, culling of existing breeding animals was at random on age and reproductive performance. The effect of additional culling of existing breeding animals when a replacement with better individual phenotype or BLUP of breeding value was available also was evaluated. Genetic gain was greater for selection on BLUP than on individual phenotype, but relative differences narrowed with increasing heritability. At yr 10 the relative advantage of selection on BLUP was 55% for h² = .10, 25% for h² = .30 and 10% for h² = .60. Culling when a replacement with better individual phenotype or BLUP of breeding value was available resulted in considerably increased genetic progress (34% to 57%). The proportional effect of culling on rate of genetic gain was relatively independent of heritability and type of selection. Inbreeding (F) was higher with selection on BLUP (F = .27 to .38 at yr 10) than on individual phenotype (F = .17 to .22 at yr 10). As heritability increased, rate of inbreeding increased for selection on individual phenotype, but rate of inbreeding tended to decrease with increasing heritability for selection on BLUP. Genetic variance was reduced more with selection on BLUP, but rate of response was still greater than with selection on individual phenotype because of greater accuracy of evaluation.

¹ Financial support was provided by the Natural Sci. and Engineering Res. Council of Canada, the Ontario Pork Producers' Marketing Board and the Ontario Ministry of Agric. and Food.

² Centre for Genetic Improvement of Livestock, Dept. of Anim. and Poultry Sci.