Herdabilidade e correlações quanto a peso, perímetro escrotal e escores visuais à desmama, em bovinos Canchim
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Data
2010-06-01
Autores
Barichello, Fabiana [UNESP]
Alencar, Maurício Mello de
Torres Júnior, Roberto Augusto de Almeida
Silva, Luiz Otávio Campos da
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Editor
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Resumo
O objetivo deste trabalho foi estabelecer o modelo mais adequado para avaliação genética de bovinos Canchim e estimar os parâmetros genéticos de características produtivas à desmama. Foram utilizados dados de: 12.103 animais, quanto ao peso (PD); 5.278, quanto ao perímetro escrotal (PE); 8.343, quanto ao escore visual da conformação frigorífica (CF); 9.111, quanto ao escore de umbigo (UM); e 7.986, quanto ao escore de pelame (PEL). Os modelos estatísticos incluíram os efeitos fixos e os efeitos aleatórios genéticos aditivos direto, materno e de ambiente permanente materno, em diferentes combinações. As análises foram feitas pelo método da máxima verossimilhança restrita livre de derivadas. O modelo completo foi o mais adequado para PD, PE, CF e UM, enquanto o modelo com uso apenas dos efeitos genéticos aditivos direto e materno foi o mais adequado para PEL. As estimativas de herdabilidade direta foram 0,17, 0,13, 0,20, 0,18, e 0,52 para PD, PE, CF, UM e PEL, respectivamente, o que indica a possibilidade de se obter progresso genético por meio da seleção para essas características, principalmente para PEL. As correlações genéticas aditivas diretas entre as características variaram de -0,16 a 0,61. As correlações entre PD e PE e entre PD e CF indicam que a seleção para PD deve proporcionar ganho genético em PE e CF
The objective of this study was to establish the best-fit model for the genetic evaluation of Canchim cattle and to estimate the genetic parameters for productive characters at weaning. The data used were related to: 12,103 animals, for weight (PD); 5,278, for scrotal circumference (PE), 8,343, for slaughter conformation visual score (CF); 9,111, for sheath and navel scores (UM), and 7,986, for hair coat score (PEL). Statistical models included fixed effects and random additive direct, maternal and maternal permanent environmental effects, in different combinations. The analyses were done by the derivative-free restricted maximum likelihood method. The complete model was the most suited for PD, PE, CF and UM, while the model with only additive direct and additive maternal random effects was the best for PEL. Direct heritability estimates were 0.17, 0.13, 0.20, 0.18, and 0.52 for PD, PE, CF, UM and PEL, respectively, which indicates that it is possible to obtain genetic progress through selection for these traits, mainly for PEL. The additive direct genetic correlations among traits varied from -0.16 to 0.61. The correlations between PD and PE and between PD and CF indicate that selection for PD should result in genetic gain in PE and CF
The objective of this study was to establish the best-fit model for the genetic evaluation of Canchim cattle and to estimate the genetic parameters for productive characters at weaning. The data used were related to: 12,103 animals, for weight (PD); 5,278, for scrotal circumference (PE), 8,343, for slaughter conformation visual score (CF); 9,111, for sheath and navel scores (UM), and 7,986, for hair coat score (PEL). Statistical models included fixed effects and random additive direct, maternal and maternal permanent environmental effects, in different combinations. The analyses were done by the derivative-free restricted maximum likelihood method. The complete model was the most suited for PD, PE, CF and UM, while the model with only additive direct and additive maternal random effects was the best for PEL. Direct heritability estimates were 0.17, 0.13, 0.20, 0.18, and 0.52 for PD, PE, CF, UM and PEL, respectively, which indicates that it is possible to obtain genetic progress through selection for these traits, mainly for PEL. The additive direct genetic correlations among traits varied from -0.16 to 0.61. The correlations between PD and PE and between PD and CF indicate that selection for PD should result in genetic gain in PE and CF
Descrição
Palavras-chave
bovinos de corte, conformação frigorífica, efeito direto, efeito materno, pelame, umbigo, beef cattle, slaughter conformation, direct effect, maternal effect, hair coat, sheath, navel
Como citar
Pesquisa Agropecuária Brasileira. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Informação TecnológicaPesquisa Agropecuária Brasileira, v. 45, n. 6, p. 563-570, 2010.