Interação pai–avô-materno na estimativa de (co) variâncias, e tendência genética do crescimento pré-desmama em gado nelore
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Data
2006-12
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Editor
Jose Henrique Stringhini
Resumo
Adjusted weights at 120 (P120) and 240 (P240) days
of age from 8,084 Nellore calves of both sexes were used to
obtain estimate of (co)variance components and predictions
of breeding values. Calves were born between 1987 and
1997 and raised on pasture in 31 herds. The complete mixed
model for each trait included the fixed effects of
contemporary group (herd-year-season-sex-management
group) and six cow age at calving classes (2, 3, 4, 5, 6 to 9,
and 10 years and older cows), and random additive genetic
effects of animal (direct and maternal), maternal permanent
environmental, sire x maternal grandsire interaction (PAM)
and residual. Inclusion of PAM interaction explained
between 2.8 and 3.1 % of the phenotypic variance, and
caused a reduction in direct and maternal variances and an increase in direct-maternal covariances. Direct heritabilities
diminished from 0.24 to 0.20 (P120), and from 0.24 to 0.19
(P240). Corresponding maternal heritabilities decreased from
0.17 to 0.13 and from 0.20 to 0.16. Direct-maternal genetic
correlations increased from 0.05 to 0.29 (P120), and from -
0.12 to 0.01 (P240), indicating no antagonism. Figures of
annual breeding value means showed scarce or any progress
during the analyzed period, particularly on maternal ability.
Intensive use of few sires could be a major factor
contributing to these results. The PAM interaction effect
and the genetic trend must be investigated further on a
database including recent information.
Descrição
Palavras-chave
(Co)variâncias maternais, Interação pai–avô-materno, Tendência genética, (Co)variances, Genetic trend, Sire–maternal grandisre interaction
Citação
REYES, Arcadio de Los; ELZO, Mauricio Aguirre; SANCHES, Ana Christina; LÔBO, Raysildo Barbosa; BEZERRA, Luiz Antonio Framartino. Interação pai–avô-materno na estimativa de (co) variâncias, e tendência genética do crescimento pré-desmama em gado nelore. Ciência Animal Brasileira, Goiânia, v. 7, n. 4, p. 365-371,out./dez. 2006. Disponível em: <https://www.revistas.ufg.br/vet/article/view/857/1179>.