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Unformatted text preview: L. A. Case, M. J. Kelly, S. P. Miller and B. J. Wood Meleagris gallopavo ) Genotype × environment interaction as it relates to egg production in turkeys ( doi: 10.2527/jas.2009-2004 originally published online February 26, 2010 2010, 88:1957-1966. J ANIM SCI http://jas.fass.org/content/88/6/1957 the World Wide Web at: The online version of this article, along with updated information and services, is located on www.asas.org by guest on June 14, 2011 jas.fass.org Downloaded from ABSTRACT: Genotype × environment (G×E) inter- actions can reduce the accuracy of a model to predict the performance of an animal and have an undesirable influence if not accounted for when estimating breeding values. Consequently, identification of these G×E is necessary when considering a turkey breeding program. Reranking based on the genetic prediction of turkey egg production, fertility, and hatchability in different sea- sons was indicative of a potential G×E interaction. Quantification of the G×E interactions was based on the genetic correlation estimated when traits were ex- pressed in different seasons. Egg production was ex- pressed as the percentage of days with an egg produced; fertility represented the proportion of hatched eggs that contained a fertile embryo; and hatchability was de- fined as the percentage of fertile eggs that produced a live bird. Variance components and heritability for egg production, fertility, and hatchability were estimated using ASReml. The heritability (h 2 ) of egg production was calculated to be 0.32 for both lines with the pheno- typic (σ p 2 ) and genetic (σ g 2 ) variance, 141.3 and 45.58 (percent days with egg produced) 2 and 118.3 and 38.35 (percent days with egg produced) 2 for female and male lines, respectively. The h 2 estimates for fertility were 0.08 in both lines with σ p 2 and σ g 2 of 293.3% 2 and 24.03% 2 , and 576.9% 2 and 48.43% 2 for female and male lines, respectively. The hatchability h 2 , σ p 2 , and σ g 2 estimates were 0.09, 267.1% 2 , and 24.44% 2 , respectively, for the female line and 0.15, 582.2% 2 , and 90.01% 2 for the male line, respectively. Based on an animal model, the vari- ance components were used to calculate estimated breeding values for each trait. The annual fluctuation in estimated breeding values resulted in the need to evaluate egg number, fertility, and hatchability as 2 traits, summer and winter lay. The correlation between the 2 traits was less than unity (female line: r egg production = 0.76, r fertility = −0.20, r hatchability = 0.75 and male line: r egg production = 0.86, r fertility = 0.19, r hatchability = 0.68) sug- gesting a G×E interaction, and animals will significant- ly rerank in genetic predictions for these reproductive phenotypes in different seasons of lay. Egg production, fertility, and hatchability in turkeys could be consid- ered as 2 distinct traits in an animal model based on season of lay....
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This note was uploaded on 01/26/2012 for the course ECON 2272 taught by Professor Gay during the Spring '08 term at Birmingham-Southern College.
- Spring '08