Heterogeneity of variances in the genetic groups formed by the Canchim breed

Revista Brasileira de Zootecnia

Freitas, Alfredo Ribeiro de³  Martins, Elias Nunes¹  Alencar, Maurício Mello de³  Oliveira, Carlos Antonio Lopes de² 

[1] Universidade Estadual de Maringá;Universidade Estadual do Mato Grosso do Sul, Aquidauana;EMBRAPA, São Carlos

关键词: Canchim breed;    genetic evaluations;    heterogeneity of variances   IntroduçãoA heterogeneidade de variâncias dentro de níveis de efeitos fixos tem sido verificada por diversos autores;    em se tratando de características de produção de leite e desenvolvimento ponderal (WINKELMAN e SCHAEFFER;    1988;    DONG e MAO;    1990;    TORRES;    1998;    RODRIGUEZ-ALMEIDA et al;   

DOI  :  10.1590/S1516-35982001000500012

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

- Variance components were estimated for the characteristic weights at 365 and 550-days of age of animals from genetic groups used on Canchim breed development. The objective was to verify the occurrence of heterogeneity variance among the genetic groups and the its possible effect during the ranking of animals, in the genetic evaluation. The estimates were obtained for the software MTDFREML. The strategy used to estimate the components of variance for both characteristics was to consider the expression of the characteristics in each genetic group as a different characteristic. The different models were tested in order to verify difference in the estimates of variance components for differents genetic groups. The estimates of variance components and classifications of the betters animals were different, for models one-trait and denominated three-trait. During the genetic evaluation process, the results were 83.7, 86.6 and 89.3% of the selected individuals there were two common classifications for the weight at 365 days, taking into account the entire set of data, males and females, respectively. For the weight at 550 days, 75.5, 72.5 and 69.3% were common between the two classifications for males, females and for the whole set of data, respectively. The results showed an existence of heterogeneous variances for the genetic groups used during the formation of the Canchim breed, for weight 365 and 550 days of age.

【 授权许可】

CC BY-NC