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Titolo: HETEROGENEITY OF VARIANCE FOR TYPE TRAITS IN THE MONTBELIARDE CATTLE BREED
Autore: ROBERTGRANIE C; DUCROCQ V; FOULLEY JL;
 Indirizzi:
 INRA,CTR RECH JOUY EN JOSAS,GENET QUANTITAT & APPL STN F78352 JOUY EN JOSAS FRANCE
 Titolo Testata:
 Genetics selection evolution
fascicolo: 6,
volume: 29,
anno: 1997,
pagine: 545  570
 SICI:
 0999193X(1997)29:6<545:HOVFTT>2.0.ZU;2A
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 INTRACLASS CORRELATIONS; UNITEDSTATES HOLSTEINS; MAXIMUMLIKELIHOOD; ENVIRONMENTAL VARIANCES; PHENOTYPIC VARIANCES; CONFORMATION TRAITS; GENETIC EVALUATIONS; RESIDUAL VARIANCES; EMALGORITHM; COMPONENTS;
 Keywords:
 HETEROSKEDASTICITY; MIXED MODEL; GENOTYPE X ENVIRONMENT INTERACTION; EM ALGORITHM; REML ESTIMATION;
 Tipo documento:
 Article
 Natura:
 Periodico
 Citazioni:
 54
 Recensione:
 Indirizzi per estratti:



 Citazione:
 C. Robertgranie et al., "HETEROGENEITY OF VARIANCE FOR TYPE TRAITS IN THE MONTBELIARDE CATTLE BREED", Genetics selection evolution, 29(6), 1997, pp. 545570
Abstract
This paper presents and discusses the estimation of genetic and residual (co) variance components for conformation traits recorded in different environments using mixed linear models. Testing procedures for genetic parameters (genetic correlations between environments constant or equal to one, genetic correlation equal to one and constant intraclass correlations, homogeneity of variancecovariance components) are presented. These hypotheses were described via heteroskedastic univariate sire models taking into account genotype x environment interaction. An expectationmaximization (EM) algorithm was proposed for calculating restricted maximum likelihood (REML) estimates of the residual andgenetic components of variances and covariances. Likelihood ratio tests were suggested to assess hypotheses concerning genetic parameters. The procedures presented in the paper were used to analyze and to detect sources of variation on conformation traits in the Montbeliarde cattle breed using 24 301 progeny records of 528 sires. On all variablesanalyzed, several sources (stage of lactation, classifiers, type of housing) of heterogeneity of residual and genetic variances were clearly highlighted, but intraclass correlations between environments of type traits remained generally constant.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 12:31:16