Efeitos ambientais e genéticos sobre escores visuais e ganho de peso à desmama de animais formadores da raça Brangus
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Data
2009-02-01
Autores
Queiroz, Sandra Aidar de [UNESP]
Costa, Gabriela Zoccolaro
Oliveira, João Ademir de [UNESP]
Fries, Luiz Alberto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
Estudaram-se os efeitos da idade da vaca ao parto e da idade do animal à desmama, bem como os efeitos genéticos aditivo direto e materno e da heterozigose individual, sobre os escores visuais de conformação, precocidade e musculatura e ganho de peso do nascimento à desmama, de animais formadores da raça Brangus. Foram analisados 53.683, 45.136, 52.937 e 56.471 dados de conformação, precocidade e musculatura à desmama e ganho de peso do nascimento à desmama, respectivamente, de animais nascidos entre 1986 e 2002, provenientes do arquivo zootécnico da empresa Gensys Consultores Associados S/C Ltda. Os efeitos de ambiente e genéticos sobre as características em estudo foram analisados pelo método de quadrados mínimos usando modelos matemáticos que incluíram grupo de contemporâneos como variável classificatória e a idade da vaca ao parto, a idade do animal à desmama e os efeitos aditivo direto e materno e da heterozigose individual como co-variáveis. Todos os efeitos incluídos nos modelos afetaram significativamente as características avaliadas, com exceção do efeito da idade da vaca ao parto sobre o ganho de peso do nascimento à desmama e do efeito aditivo materno sobre todas as características estudadas. Os efeitos ambientais e genéticos revelaram-se importantes fontes de variação para as características estudadas e devem, pois, ser considerados na distinção e comparação dos animais para seleção.
The objective of this work was to study the effects of age of cow at calving (IPV) and age of calf at weaning (IDD) as well as the direct additive genetic effects (AD) and maternal (AM), and the individual heterozygosity (HI) on visual scores of conformation (CD), precocity (PD) and musculature (MD) and average daily weight gain from birth to weaning (GND), for animals used to form the Brangus breed. The study analyzed 53,683, 45,136, 52,937 and 56,471 records on CD, PD, MD and GND, respectively for animals born from 1986 to 2002. The data were provided by Gensys Consultores Associados S/C Ltda. The environmental and genetics effects on these traits were analyzed using the least square method applying mathematical models that included fixed effects of contemporary group (GC) and IPV, IDD, AD, AM and HI as covariates. All environmental effects included in the model showed significant influence on the evaluated traits at weaning, except for IDD on GND and AM on all traits. All traits were significantly influenced by AD and HI. These results indicated that environmental and genetic effects were important sources of variation for these traits and, consequently, they should be considered in genetic evaluations.
The objective of this work was to study the effects of age of cow at calving (IPV) and age of calf at weaning (IDD) as well as the direct additive genetic effects (AD) and maternal (AM), and the individual heterozygosity (HI) on visual scores of conformation (CD), precocity (PD) and musculature (MD) and average daily weight gain from birth to weaning (GND), for animals used to form the Brangus breed. The study analyzed 53,683, 45,136, 52,937 and 56,471 records on CD, PD, MD and GND, respectively for animals born from 1986 to 2002. The data were provided by Gensys Consultores Associados S/C Ltda. The environmental and genetics effects on these traits were analyzed using the least square method applying mathematical models that included fixed effects of contemporary group (GC) and IPV, IDD, AD, AM and HI as covariates. All environmental effects included in the model showed significant influence on the evaluated traits at weaning, except for IDD on GND and AM on all traits. All traits were significantly influenced by AD and HI. These results indicated that environmental and genetic effects were important sources of variation for these traits and, consequently, they should be considered in genetic evaluations.
Descrição
Palavras-chave
conformation, environmental effects, growth traits, individual heterozygosity, musculature, precocity, Características de crescimento, conformação, efeitos de ambiente, heterozigose individual, musculatura, precocidade
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 38, n. 2, p. 277-283, 2009.