Estimation of variance components, genetic parameters and genetic trends for litter size of swines

Revista Brasileira de Zootecnia

Leandro Barbosa²  Paulo Sávio Lopes¹  Adair José Regazzi¹  Robledo De Almeida Torres¹  Mário Luiz Santana Júnior¹  Renata Veroneze¹ 

[1] ,Universidade Federal de Sergipe

关键词: genetic trend;    heritability;    number of piglets;    REML;    repeatability model;    reproductive traits;    características reprodutivas;    herdabilidade;    modelo de repetibilidade;    número de leitões nascidos;    REML;    tendência genética;   

DOI  :  10.1590/S1516-35982010001000008

来源: SciELO

【 摘 要 】

Records of Large White breed animals were used to estimate variance components, genetic parameters and trends for the character total number of born piglets (TNBP) as measure of litter size. For obtaining variance components and genetic parameters, it was used the Restricted Maximum Likelihood Method using MTDFREML software. Two mixed models (additive and repeatability) were evaluated. The additive model contained fixed effect of the contemporary group and the following random effects: direct additive genetic and residual effect for the first parturition. Repeatability model had the same effects of the additive model plus parturition order fixed effect and non-correlated animal permanent environment random effect for the second, third and forth parturition. Direct additive heritability estimates for TNBP were 0.15 and 0.20 for the additive and repeatability models, respectively. The estimate of the ration among variance of the non-correlated effect of animal permanent environment effect and the phenotypic variance, expressed as total variance proportion (c2) was 0.09. The estimates of yearly genetic trends obtained in the additive and repeatability models have similar behaviors (0.02 piglets/sow/year).

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