Herdabilidades e correlações genéticas de características de machos e fêmeas, em um rebanho bovino da raça Canchim
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Data
2003-12-01
Autores
Gianlorenço, Viviane Karina
Alencar, Maurício Mello de
Toral, Fábio Luiz Buranelo [UNESP]
Mello, Silvio de Paula
Freitas, Alfredo Ribeiro de
Barbosa, Pedro Franklin
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
O objetivo deste trabalho foi estimar as herdabilidades e as correlações genéticas do peso (P12) e do perímetro escrotal (PE12) de machos aos 12 meses de idade, da idade de descarte (TPR, tempo de permanência no rebanho) de fêmeas e do número (ND10) e de quilogramas (QD10) de bezerros desmamados pelas fêmeas em até dez anos de idade, em um rebanho da raça Canchim. Foram utilizadas 1.370, 826, 826, 2.726 e 1.051 observações de TPR, ND10, QD10, P12 e PE12, respectivamente. As estimativas dos componentes de (co)variância foram obtidas pelo método bayesiano, para todas as características em questão, P12, PE12, TPR, ND10 e QD10. O modelo estatístico incluiu, além dos efeitos aleatórios genético aditivo direto e residual, os efeitos fixos de ano de nascimento do animal para todas as características, de mês de nascimento para P12 e PE12 e da covariável idade do animal para PE12. As estimativas de herdabilidade, obtidas pelas análises unicaráter foram iguais a 0,38; 0,52; 0,24; 0,33 e 0,34 para P12, PE12, TPR, ND10 e QD10, respectivamente, indicando que as características possuem variação genética aditiva suficiente para apresentar boa resposta à seleção. As correlações genéticas de TPR (0,33 e 0,33, respectivamente), ND10 (0,38 e 0,30, respectivamente) e QD10 (0,61 e 0,41, respectivamente) com P12 e PE12, obtidas pelas análises bicaráter, sugerem que a seleção com base no peso e no perímetro escrotal dos machos não deve resultar em decréscimo no tempo de permanência das fêmeas no rebanho e no número e quilogramas de bezerros produzidos pelas fêmeas em até dez anos de idade.
The objective of this study was to estimate the heritabilities and the genetic correlations of body weight (BW12) and scrotal circumference (SC12) of males at twelve months of age and culling age (DH, days in herd) of females, and number (NW10) and kilograms (KW10) of weaned calves produced by females up to ten years of age, in a Canchim (5/8 Charolais + 3/8 Zebu) beef cattle herd. Data were composed of 1370, 826, 826, 2726 and 1051 observations of DH, NW10, KW10, BW12 and SC12, respectively. The variance and covariance components were obtained by the bayesian method, with a statistical model that included, besides the additive direct and residual random effects, the fixed effects of year of birth for all traits, month of birth for BW12 and SC12, and the covariate age for SC12. The heritability estimates, obtained by the one-trait analyses, were equal to 0.38, 0.52, 0.24, 0.33 and 0.34 for BW12, SC12, DH, NW10 and KW10, respectively, indicating that all traits have enough genetic variability to show response to selection. The genetic correlations of DH (0.33 and 0.33, respectively), NW10 (0.38 and 0.30, respectively) and KW10 (0.61 and 0.41, respectively) with BW12 and SC12, obtained by the two-trait analyses, suggest that selection for increased body weight and scrotal circumference of the males at twelve months of age will not result in decreased days in herd for the females, and decreased number and kilograms of weaned calves produced by the females up to ten years of age.
The objective of this study was to estimate the heritabilities and the genetic correlations of body weight (BW12) and scrotal circumference (SC12) of males at twelve months of age and culling age (DH, days in herd) of females, and number (NW10) and kilograms (KW10) of weaned calves produced by females up to ten years of age, in a Canchim (5/8 Charolais + 3/8 Zebu) beef cattle herd. Data were composed of 1370, 826, 826, 2726 and 1051 observations of DH, NW10, KW10, BW12 and SC12, respectively. The variance and covariance components were obtained by the bayesian method, with a statistical model that included, besides the additive direct and residual random effects, the fixed effects of year of birth for all traits, month of birth for BW12 and SC12, and the covariate age for SC12. The heritability estimates, obtained by the one-trait analyses, were equal to 0.38, 0.52, 0.24, 0.33 and 0.34 for BW12, SC12, DH, NW10 and KW10, respectively, indicating that all traits have enough genetic variability to show response to selection. The genetic correlations of DH (0.33 and 0.33, respectively), NW10 (0.38 and 0.30, respectively) and KW10 (0.61 and 0.41, respectively) with BW12 and SC12, obtained by the two-trait analyses, suggest that selection for increased body weight and scrotal circumference of the males at twelve months of age will not result in decreased days in herd for the females, and decreased number and kilograms of weaned calves produced by the females up to ten years of age.
Descrição
Palavras-chave
bovinos de corte, longevidade de fêmeas, perímetro escrotal, peso, produtividade de fêmeas, beef cattle, Canchim, days in herd, female productivity, scrotal circumference, weight
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 32, n. 6, p. 1587-1593, 2003.