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3 results on '"co-variance estimates"'

1. EFEITOS DA INCLUSÃO OU NÃO DA COVARIÂNCIA GENÉTICA DIRETA-MATERNAL NO MODELO E DOS VALORES REAIS DAS (CO)VARIÂNCIAS SOBRE SUAS ESTIMATIVAS PARA PESO À DESMAMA EM BOVINOS DE CORTE

Author

JORGE LUIS FERREIRA, ARCADIO DE LOS REYES BORJAS, ROBERTO CARVALHEIRO, and RAYSILDO BARBOSA LÔBO

Subjects
cattle, direct-maternal genetic correlation, co-variance estimates, simulation., Agriculture, Animal culture, SF1-1100
Abstract

This study aimed to compare estimates of (co)variances considering the effect of direct maternal genetic correlation (-0,50; -0,25; +0,25; +0,50); the ratios between the direct and maternal genetic variances (75:75; 50:100; 100:50) and two models which included (M2) or not (M1) the direct maternal genetic covariance. Stochastic simulation of twenty replicates of a closed and randomly mated herd of cattle was carried out for twenty years of selection. The base population was not related, nonselected and randomly sampled. (Co)variance estimates were obtained under single trait animal model using MTDFREML application. The model was not significant on estimates of maternal permanent environmental variance. The genetic direct-maternal correlation influenced all (co)variance estimates significantly (P

Published
2011

2. EFEITOS DA INCLUSÃO OU NÃO DA COVARIÂNCIA GENÉTICA DIRETA-MATERNAL NO MODELO E DOS VALORES REAIS DAS (CO)VARIÂNCIAS SOBRE SUAS ESTIMATIVAS PARA PESO À DESMAMA EM BOVINOS DE CORTE.

Author

Ferreira, Jorge Luis, De Los Reyes Borjas, Arcadio, Roberto Carvalheiro, Roberto, and Lôbo, Raysildo Barbosa

Subjects
BEEF cattle weight, ANIMAL genetics, SIMULATION methods & models, STATISTICAL correlation, ANALYSIS of variance, ESTIMATION theory, MATHEMATICAL models
Abstract

This study aimed to compare estimates of (co)variances considering the effect of direct maternal genetic correlation (-0,50; -0,25; +0,25; +0,50); the ratios between the direct and maternal genetic variances (75:75; 50:100; 100:50) and two models which included (M2) or not (M1) the direct maternal genetic covariance. Stochastic simulation of twenty replicates of a closed and randomly mated herd of cattle was carried out for twenty years of selection. The base population was not related, nonselected and randomly sampled. (Co)variance estimates were obtained under single trait animal model using MTDFREML application. The model was not significant on estimates of maternal permanent environmental variance. The genetic direct-maternal correlation influenced all (co)variance estimates significantly (P<0,05). The ratios of genetic direct and maternal variances significantly affected (P<0,05) only estimates of genetic direct and maternal variances. Regarding negative direct-maternal genetic correlation, M1 underestimated direct and maternal variances while overestimated both when that correlation was positive. Reliable and accurate (co)variance estimates for weaning weight in beef cattle depend on the adequacy of the model as well as their actual values. [ABSTRACT FROM AUTHOR]

Published
2011
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3. Efeitos da inclusão ou não da covariância genética direta-maternal no modelo e dos valores reais das (CO)variâncias sobre suas estimativas para peso à desmama em bovinos de corte

Author

Raysildo Barbosa Lôbo, Arcadio de los Reyes Borjas, Roberto Carvalheiro, and Jorge Luís Ferreira

Subjects
direct-maternal genetic correlation, General Veterinary, simulation, lcsh:S, Variance (accounting), Beef cattle, Biology, Genetic correlation, Correlation, lcsh:Agriculture, Animal model, cattle, co-variance estimates, Statistics, VARIAÇÃO GENÉTICA (ESTIMATIVA), Trait, Herd, Animal Science and Zoology, lcsh:Animal culture, Selection (genetic algorithm), lcsh:SF1-1100
Abstract

This study aimed to compare estimates of (co)variances considering the effect of direct maternal genetic correlation (-0,50; -0,25; +0,25; +0,50); the ratios between the direct and maternal genetic variances (75:75; 50:100; 100:50) and two models which included (M2) or not (M1) the direct maternal genetic covariance. Stochastic simulation of twenty replicates of a closed and randomly mated herd of cattle was carried out for twenty years of selection. The base population was not related, non-selected and randomly sampled. (Co)variance estimates were obtained under single trait animal model using MTDFREML application. The model was not significant on estimates of maternal permanent environmental variance. The genetic direct-maternal correlation influenced all (co)variance estimates significantly (P

Published
2011

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