Estimation of variances due to direct and maternal effects for growth traits of Nelore cattle2

Eler, Joanir Pereira; Vleck, L.D. Van; Ferraz, José Bento Sterman; Lôbo, Raysildo Barbosa

doi:10.2527/1995.73113253x

Cited by 113 publications

(112 citation statements)

References 20 publications

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“…The estimates for weaning weight agreed with values reported for Hereford cattle (Meyer, (Eler et al, 1995), Wakwa and Gudali cattle (Tawah et al, 1993), and Mashona cattle (Khombe et al, 1995). For yearling and final weights, the estimates of direct, but not maternal, heritability were consistent with most published estimates.…”

Section: Discussionsupporting

confidence: 80%

“…Maternal effects would be expected to diminish at these ages because the animals no longer depend on their mothers. Relatively high estimates of h 2 were also reported by Eler et al (1995) and Mackinnon et al (1991) at yearling and later ages, respectively. These authors both also suggested that for animals raised on pasture with little or no feed supplement, the length of time between weaning and yearling ages may not be enough to buffer maternal effects present at weaning.…”

Section: Discussionmentioning

confidence: 70%

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Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

1999

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Estimates of genetic parameters for birth (N = 3909), weaning (N = 3425), yearling (N = 2764) and final (N = 2144) weights were obtained from the records of Gobra cattle collected at the Centre de Recherches Zootechniques de Dahra, Senegal. Three animal models were fitted to obtain estimates by REML using an average information (AI) approach. Model 1 considered random direct, maternal genetic and maternal permanent environmental effects. In model 2, a general grandmaternal effect was added to the random effects considered in model 1, and in model 3, the general grandmaternal effect was divided into grandmaternal genetic and grandmaternal permanent environmental effects. All models allowed covariances among genetic effects. The inclusion of grandmaternal effects in models 2 and 3 did not change the estimates of the genetic parameters compared to model 1. Variances attributable to grandmaternal effects became negative and were set close to zero, except for yearling weight for which grandmaternal heritability was 0.03 ± 0.03. The estimates for direct and maternal heritabilities were, respectively, 0.08 ± 0.03 and 0.03 ± 0.02 for birth, 0.20 ± 0.05 and 0.21 ± 0.05 for weaning, 0.26 ± 0.07 and 0.16 ± 0.07 for yearling and 0.14 ± 0.06 and 0.16 ± 0.06 for final weights. The estimates of the genetic correlation between direct and maternal effects for birth, weaning, yearling and final weights were -0.17 ± 0.40, -0.58 ± 0.32, -0.52 ± 0.34 and -0.34 ± 0.37, respectively. For yearling weight with grandmaternal heritability estimated to be only 0.03, model 3 gave estimates of the genetic correlation between direct and grandmaternal effects and between maternal and grandmaternal effects of 0.28 ± 0.48 and -0.33 ± 0.67, respectively. Estimates of direct and maternal heritabilities were unchanged when grandmaternal effects were not included in the model.
Foram obtidas as estimativas dos pesos ao nascimento (N = 3909), ao desmame (N = 3425), com 1 ano de idade (N = 2764) e final (N = 2144) a partir dos registros de gado Gobra coletados no Centro de Pesquisas em Zootecnia de Dahra, Senegal. Três modelos animais foram adaptados para obter estimativas por REML usando uma abordagem de informação média (AI). O modelo 1 considerou os efeitos ambientais aleatórios direto, genético maternal e maternal permanente. No modelo 2, um efeito geral relativo às avós foi adicionado aos efeitos aleatórios considerados no modelo 1, e no modelo 3 o efeito geral relativo às avós foi dividido em efeitos ambientais genético e permanente. Todos os modelos admitiram covariâncias entre os efeitos genéticos. A inclusão dos efeitos relativos às avós nos modelos 2 e 3 não alterou as estimativas dos parâmetros genéticos comparados com o modelo 1. As variâncias atribuíveis aos efeitos relativos às avós tornaram-se negativas e foram posicionadas próximas a zero, exceto para o peso com 1 ano, para o qual a herdabilidade relativa à avo foi 0,03 ± 0,03. As estimativas para as herdabilidades direta e maternal foram, respectivamente, 0,08 ± 0,03 e 0,03 ± 0,02 pa...

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 70%

Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

1999

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“…The correlations between direct and maternal genetic effects for all traits were always low and negative (analyses A, C and E). Similar estimates have been reported by Eler et al (1995 and for WW (−0.13) and for BW and WW (−0.33 to −0.14) of Nelore cattle, respectively, and by De Mattos et al (2000) for WW of Hereford cattle in the United States, Canada and Uruguay (−0.51 to −0.31). According to Maniatis and Pollott (2003), the negative estimates obtained for the correlation between direct and maternal genetic effects in the present study might be because of the small number of dams with weight records (18% and 19% for BW and WW, respectively).…”

Section: Resultssupporting

confidence: 86%

Genotype by production environment interaction for birth and weaning weights in a population of composite beef cattle

Júnior

Eler

Bignardi

et al. 2014

Animal

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The objectives of the present study were: (1) to evaluate the importance of genotype × production environment interaction for the genetic evaluation of birth weight (BW) and weaning weight (WW) in a population of composite beef cattle in Brazil, and (2) to investigate the importance of sire × contemporary group interaction (S × CG) to model G × E and improve the accuracy of prediction in routine genetic evaluations of this population. Analyses were performed with one, two (favorable and unfavorable) or three (favorable, intermediate, unfavorable) different definitions of production environments. Thus, BW and WW records of animals in a favorable environment were assigned to either trait 1, in an intermediate environment to trait 2 or in an unfavorable environment to trait 3. The (co)variance components were estimated using Gibbs sampling in single-, bi-or three-trait animal models according to the definition of number of production environments. In general, the estimates of genetic parameters for BW and WW were similar between environments. The additive genetic correlations between production environments were close to unity for BW; however, when examining the highest posterior density intervals, the correlation between favorable and unfavorable environments reached a value of only 0.70, a fact that may lead to changes in the ranking of sires across environments. The posterior mean genetic correlation between direct effects was 0.63 in favorable and unfavorable environments for WW. When S × CG was included in two-or three-trait analyses, all direct genetic correlations were close to unity, suggesting that there was no evidence of a genotype × production environment interaction. Furthermore, the model including S × CG contributed to prevent overestimation of the accuracy of breeding values of sires, provided a lower error of prediction for both direct and maternal breeding values, lower squared bias, residual variance and deviance information criterion than the model omitting S × CG. Thus, the model that included S × CG can therefore be considered the best model on the basis of these criteria. The genotype × production environment interaction should not be neglected in the genetic evaluation of BW and WW in the present population of beef cattle. The inclusion of S × CG in the model is a feasible and plausible alternative to model the effects of G × E in the genetic evaluations.

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“…A seleção com base na avaliação genética de características de desempenho ponderal foi implantada no Brasil de forma até surpreendente (Lôbo et al, 1994;Eler et al, 1995;Fries, 1999) e para características reprodutivas, no entanto, tem sido mais lenta.…”

Section: Introductionunclassified

Análise genética de algumas características reprodutivas e suas relações com o desempenho ponderal na raça Nelore

Pereira¹,

Eler

Ferraz

2001

Arq. Bras. Med. Vet. Zootec.

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Estimation of variances due to direct and maternal effects for growth traits of Nelore cattle2

Cited by 113 publications

References 20 publications

Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

Genotype by production environment interaction for birth and weaning weights in a population of composite beef cattle

Análise genética de algumas características reprodutivas e suas relações com o desempenho ponderal na raça Nelore

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