Parâmetros genéticos de longevidade e produtividade de fêmeas da raça Nelore

Bertazzo, Rodrigo Possa; Freitas, Rilke Tadeu Fonseca de; Gonçalves, Tarcisio de Moraes; Pereira, Idalmo Garcia; Eler, Joanir Pereira; Ferraz, José Bento Sterman; Oliveira, A.; Andrade, Ivo Francisco de

doi:10.1590/s1516-35982004000500003

Cited by 37 publications

(32 citation statements)

References 13 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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“…The maternal heritability estimate for weaning weight was similar to that described in the literature, i.e., 0.10 to 0.17 (Mercadante et al, 2000;Bertazzo et al, 2004;Boligon et al, 2008a). The maternal ability is shown in the pre-natal stage because of placental differences until the post-natal stage due to care and milk production levels.…”

Section: Resultssupporting

confidence: 78%

Study of relations among age at first calving, average weight gains and weights from weaning to maturity in Nellore cattle

Boligon

Albuquerque²,

Mercadante

et al. 2010

R. Bras. Zootec.

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-Data from 23,120 Nellore animals were used to estimate genetic parameters for age at first calving, average gains from weaning to yearling and from yearling to after yearling, weaning weight, yearling weight, after yearling weight and weight at 2 and 5 years of age. Animal models were fitted by Restricted Maximum likelihood Method. Estimate heritability for age at first calving, weaning to yearling weight gain, yearling to after yearling weight gain, weight at weaning, yearling weight, after yearling weight and weight from 2 to 5 years of age were 0.17 ± 0.01; 0.23 ± 0.03; 0.25 ± 0.03; 0.28 ± 0.02; 0.26 ± 0.03; 0.30 ± 0.03; 0.32 ± 0.02 and 0.36 ± 0.04, respectively. The genetic correlation estimates between age at first calving and weight traits ranged from -0.26 to -0.14. The genetic correlation estimates between age at first calving and average gains were also negative, but higher (-0.29 and -0.32). In general, these results indicate that selection for average gains will promote changes in age at first calving and female mature weight. Improvement in reproductive performance could be obtained with the inclusion of the age at first calving in the selection index.Key Words: beef cattle, genetic parameters, heritability, productive and reproductive traits Estudo das relações entre a idade ao primeiro parto, ganhos em peso e pesos da desmama à maturidade em bovinos da raça Nelore RESUMO -Dados de 23.120 animais da raça Nelore foram utilizados para estimar herdabilidade e correlações genéticas para a idade ao primeiro parto, o ganho em peso da desmama ao ano e do ano ao sobreano, o peso à desmama, o peso ao ano, o peso ao sobreano e os pesos aos 2 e aos 5 anos de idade. Utilizou-se o método da máxima verossimilhança restrita, em análise multicaracterística. As herdabilidades estimadas para idade ao primeiro parto, ganho da desmama ao ano, ganho do ano ao sobreano, peso à desmama, peso ao ano, peso ao sobreano e peso aos 2 aos 5 anos foram de 0,17 ± 0,01; 0,23 ± 0,03; 0,25 ± 0,03; 0,28 ± 0,02; 0,26 ± 0,03; 0,30 ± 0,03; 0,32 ± 0,02 e 0,36 ± 0,04, respectivamente. Correlações genéticas baixas e negativas foram estimadas entre a idade ao primeiro parto e os pesos medidos em diferentes idades, que variaram de -0,26 a -0,14. As correlações genéticas estimadas entre a idade ao primeiro parto e os ganhos de peso também foram negativas, porém levemente superiores (-0,29 e -0,32). Os resultados indicam que a seleção para maior ganho de peso pode reduzir a idade ao primeiro parto e aumentar o peso adulto de fêmeas da raça Nelore. Mudança genética mais rápida para diminuição da idade ao primeiro parto das fêmeas pode ser obtida com a inclusão dessa característica nos índices de seleção.Palavras-chave: bovinos de corte, características produtivas e reprodutivas, herdabilidade, parâmetros genéticos Revista Brasileira de Zootecnia

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“…As herdabilidades maternas apresentaram baixas magnitudes e foram semelhantes às descritas por Mercadante et al (2000); Cabrera et al (2001) e Bertazzo et al (2004). Por outro lado, utilizando modelos de regressão aleatória, Albuquerque & Meyer (2001), Dias et al (2006) e Nobre et al (2003) estimaram maiores herdabilidades maternas para pesos do nascimento ao sobreano.…”

Section: Resultsunclassified

Estimação de funções de covariância para características de crescimento da raça Tabapuã utilizando modelos de regressão aleatória

et al. 2010

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RESUMO -Foram utilizados 35.732 registros de peso do nascimento aos 660 dias de idade de 8.458 animais da raça Tabapuã para estimar funções de covariância utilizando modelos de regressão aleatória sobre polinômios de Legendre. Os modelos incluíram: como aleatórios, os efeitos genético aditivo direto, materno, de ambiente permanente de animal e materno; como fixos, os efeitos de grupo de contemporâneo; como covariáveis, a idade do animal à pesagem e a idade da vaca ao parto (linear e quadrática); e sobre a idade à pesagem, polinômio ortogonal de Legendre (regressão cúbica) foi considerado para modelar a curva média da população. O resíduo foi modelado considerando sete classes de variância e os modelos foram comparados pelos critérios de informação Bayesiano de Schwarz e Akaike. O melhor modelo apresentou ordens 4, 3, 6, 3 para os efeitos genético aditivo direto e materno, de ambiente permanente de animal e materno, respectivamente. As estimativas de covariância e herdabilidades, obtidas utilizando modelo bicaracter, e de regressão Estimation of covariance functions for growth traits in Tabapuã cattle using random regression modelsABSTRACT -In order to estimate covariance functions by using random regression models on Legendre polynomials, 35,732 weight records from birth to 660 days of age of 8,458 animals of Tabapuã cattle were used. The models included: as random effects, direct additive genetic effect, maternal effect, and animal and maternal permanent environmental effets; contemporary groups were included as fixed effects; and as covariables, animal age at weighing and age of dam at calving (linear and quadratic effects) and on age at weighing,, the orthogonal Legendre polynomial (cubic regression) was considered to model the mean curve of the population. Residuals effects were modeled considering seven classes of variance. The models were compared by Akaike criterion and Bayesian information criterion. The best model showed orders 4, 3, 6, and 3 for maternal and direct additive genetic effect, and maternal and animal permanent enviroment, respectively. Estimates of (co)variance and heritability obtained with the bi-trait and random regression models were similar. The heritability estimates for direct additive genetic effect obtained by the random regression models increased from birth (0.15) to 660 days of age (0.45). The greatest estimates of maternal heritability were obtained for weights measured right after birth. In general, the genetic correlation estimates were moderate to high, and they decreased as the distance between weights increased. Selection for higher weights at any age will promote weight gain from birth to 660 days of age.

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Parâmetros genéticos de longevidade e produtividade de fêmeas da raça Nelore

Cited by 37 publications

References 13 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

Study of relations among age at first calving, average weight gains and weights from weaning to maturity in Nellore cattle

Estimação de funções de covariância para características de crescimento da raça Tabapuã utilizando modelos de regressão aleatória

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