Análise genético-quantitativa de pesos aos 8, 12, 18 e 24 meses de idade em um rebanho da raça Guzerá

Mucari, Talita Buttarello; Oliveira, João Ademir de

doi:10.1590/s1516-35982003000700009

Cited by 17 publications

(13 citation statements)

References 4 publications

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“…The variation in heritabilities obtained in this study are consistent since they are within the range reported in the literature for Nellore cattle, ranging from 0.01 to 0.37 for AFC (Gressler et al, 2000;Bertazzo et al, 2004), from 0.36 to 0.71 for SC (Garnero et al, 2001;Dias et al, 2003;Yokoo et al, 2007), and from 0.08 to 0.76 for YW (Ribeiro et al, 2001;Mucari and Oliveira, 2003). Estimates of heritability (h2) for age at first calving (AFC), scrotal circumference (SC), and yearling weight (YW) along the environmental gradient.…”

Section: Resultssupporting

confidence: 91%

Reaction norms for the study of genotype-environment interaction for growth and indicator traits of sexual precocity in Nellore cattle

Lemos¹,

Chiaia²,

Berton³

et al. 2015

Genet. Mol. Res.

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ABSTRACT. The objective of this study was to quantify the magnitude of genotype-environment interaction (GxE) effects on age at first calving (AFC), scrotal circumference (SC), and yearling weight (YW) in Nellore cattle using reaction norms. For the study, 89,152 weight records of female and male Nellore animals obtained at yearling age were used. Genetic parameters were estimated with a single-trait randomregression model using Legendre polynomials as base functions. The heritability estimates were of low to medium magnitude for AFC (0.05 to 0.47) and of medium to high magnitude for SC (0.32 to 0.51) and YW (0.13 to 0.72), and increased as the environmental gradient became more favorable. The genetic correlation estimates ranged from 0.25 to 1.0 for AFC, from 0.71 to 1.0 for SC, and from 0.42 to 1.0 for YW. High Spearman correlation coefficients were obtained for the three traits, ranging from 0.97 to 0.99. The reaction norms along the environmental gradient of 10 sires each with the highest or lowest breeding value for YW predicted by single-trait analysis demonstrated more plastic phenotypes for YW and more robust phenotypes for SC. The effect of GxE was most important for YW and AFC with respect to SC. When animals are selected for higher SC or YW or lower AFC, considering or not the GxE effect, it is expected that the same animals will be selected. The reaction norms obtained based on sire breeding values along the environmental gradient showed that animals with extreme breeding values respond differently as environmental conditions improve.

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Section: Resultssupporting

confidence: 91%

Reaction norms for the study of genotype-environment interaction for growth and indicator traits of sexual precocity in Nellore cattle

Lemos¹,

Chiaia²,

Berton³

et al. 2015

Genet. Mol. Res.

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“…However, the correlation obtained for BW12 and BW18 (0.30 6 0.11) was lower than that found by Santos et al (2005) for the Nellore breed (0.97) and by Malhado et al (2002) and Mucari and Oliveira (2003) for the Guzerá breed (0.65 and 0.62, respectively). Nonetheless, the high environmental correlation (0.80 6 0.02) indicated that not only were these traits influenced by additive action of the same genes but also there was a non-additive and/or environmental genetic association.…”

Section: Discussioncontrasting

confidence: 54%

“…Body weight (BW) measured at different ages is often used with the aim of identifying the most productive animals. BW measurements present heritability of medium to high magnitude and are highly correlated with each other, thus indicating that BW data obtained at young ages can be used as selection criteria for Zebu breeds (Garnero et al, 2001;Mucari and Oliveira, 2003). These authors used weights at different ages that were adjusted by means of linear interpolation and, in this way, they corrected for weight measurements made at different ages.…”

Section: Introductionmentioning

confidence: 99%

Heritability estimates and genetic correlations for body weight and scrotal circumference adjusted to 12 and 18 months of age for male Nellore cattle

Frizzas

Grossi

Buzanskas

et al. 2009

Animal

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Heritability estimates and genetic correlations were obtained for body weight and scrotal circumference, adjusted, respectively, to 12 (BW12 and SC12) and 18 (BW18 and SC18) months of age, for 10 742 male Nellore cattle. The adjustments to SC12 and SC18 were made using a nonlinear logistic function, while BW12 and BW18 were obtained by linear adjustment. The contemporary groups (CGs) were defined from animals born on the same farm, in the same year and birth season. The mean heritability estimates obtained using the restricted maximum likelihood method in bi-trait analysis were 0.25, 0.25, 0.29 and 0.42 for BW12, BW18, SC12 and SC18, respectively. The genetic correlations were 0.30 6 0.11, 0.21 6 0.13, 0.21 6 0.11, 20.08 6 0.15, 0.16 6 0.12 and 0.89 6 0.04 between the traits BW12 and BW18; BW12 and SC12; BW12 and SC18; BW18 and SC12; BW18 and SC18; and SC12 and SC18. The heritability for SC18 was considerably greater than for SC12, suggesting that this should be included as a selection criterion. The genetic correlation between BW18 and SC12 was close to zero, indicating that these traits did not influence each other. The contrary occurred between SC12 and SC18, indicating that selection using one of these could alter the other. Because of the mean magnitudes of heritabilities in the various measurements of weight and scrotal perimeter, it is suggested that the practice of individual selection for these traits is possible.

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“…Ferraz Filho et al (2002) relataram ganhos inferiores, de 0,08% de aumento, na média fenotípica do peso aos 205 dias de animais Tabapuã. Mucari & Oliveira (2003) também relataram pequenos ganhos genéticos anuais em características de crescimento de um rebanho Guzerá: 0,10% de aumento da média fenotípica no peso aos oito meses de idade; 0,02% no peso aos 12 meses de idade; 0,06% no peso aos 18 meses de idade; e 0,14% no peso aos 24 meses de idade.…”

Section: Resultsunclassified

Tendências genéticas para escores visuais de conformação, precocidade e musculatura à desmama de bovinos Nelore

Forni

Federici²,

Albuquerque

2007

R. Bras. Zootec.

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RESUMO -Os objetivos neste estudo foram estimar os coeficientes de herdabilidade e a mudança genética nos escores visuais de conformação (C), precocidade (P) e musculatura (M) à desmama de bovinos Nelore e avaliar as mudanças promovidas pelo programa de seleção ao qual os animais foram submetidos. Foram utilizados dados de 56.076 animais nascidos entre 1990 e 2002. Os componentes de variância foram estimados por máxima verossimilhança restrita e os valores genéticos foram preditos pelo método dos modelos mistos aplicando-se um modelo animal. As tendências genéticas foram estimadas pela regressão dos valores genéticos sobre o ano de nascimento dos animais. Os coeficientes de herdabilidade do efeito direto estimados foram de 0,122±0,012; 0,153±0,012; e 0,124±0,012 e, para o efeito materno, de 0,043±0,010; 0,038±0,009; e 0,056±0,010 para C, P e M, respectivamente. As tendências genéticas diretas estimadas foram de 0,013; 0,022 e 0,018 pontos de escore ao ano para C, P e M, respectivamente, o que representa incremento anual de 0,42; 0,67 e 0,60% ao ano em relação à média fenotípica. As tendências genéticas do efeito materno foram de -0,0020; -0,0010; e -0,0009 pontos de escore ao ano para C, P e M, respectivamente, o que representa uma mudança anual de -0,07; -0,03; e -0,03% na média fenotípica da população. Palavras-chave: crescimento, gado de corte, herdabilidadeGenetic trends in Nelore cattle selected for visual scores of conformation, precocity and musculature at weaning ABSTRACT -The aims of this study were to estimate heritability coefficients and genetic trends for visual scores of conformation (C), finishing precocity (P) and musculature (M) in Nelore beef cattle. Variance components and heritability coefficients were estimated by restrict maximum likelihood and breeding values were predicted by an animal mixed model using data from 56,076 animals born between 1990 and 2002. Genetic trends for each trait were estimated by the regression of breeding values on animal birth year. Heritability estimates for direct effect of C, P and M were respectively 0.122±0.012, 0.153±0.012 and 0.124±0.012. In the same order of traits, maternal effect heritability estimates were respectively 0.043±0.010, 0.038±0.009 and 0.056±0.010. Direct genetic trend estimates were respectively 0.013, 0.022 and 0.018 score units per year for C, P and M, which represent 0.42, 0.67, and 0.60% of the phenotypic average. Maternal effect genetic trends were respectively -0.0020, -0.0010 and -0.0009 for C, P and M, which represent -0.07, -0.03, and -0.03% of the phenotypic average of the population.

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Análise genético-quantitativa de pesos aos 8, 12, 18 e 24 meses de idade em um rebanho da raça Guzerá

Cited by 17 publications

References 4 publications

Reaction norms for the study of genotype-environment interaction for growth and indicator traits of sexual precocity in Nellore cattle

Reaction norms for the study of genotype-environment interaction for growth and indicator traits of sexual precocity in Nellore cattle

Heritability estimates and genetic correlations for body weight and scrotal circumference adjusted to 12 and 18 months of age for male Nellore cattle

Tendências genéticas para escores visuais de conformação, precocidade e musculatura à desmama de bovinos Nelore

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