Efeitos Da Inclusão Ou Não Da Covariância Genética Direta-Maternal No Modelo E Dos Valores Reais Das (Co)variâncias Sobre Suas Estimativas Para Peso À Desmama Em Bovinos De Corte

Ferreira, Jorge Luís; Borjas, Arcádio de los Reyes; Carvalheiro, Roberto; Lôbo, Raysildo Barbosa

doi:10.5216/cab.v12i3.5503

Cited by 3 publications

(4 citation statements)

References 14 publications

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“…However, consistent with findings from previous studies, it is possible to confirm that cytoplasmic lineage effects and direct and maternal genetic covariance are not significant for post-weaning traits and should not be included in the genetic evaluation (Guterres et al, 2007;Ferreira et al, 2011). Thus, future studies should focus on the use of the mitochondrial genome, which may contribute to a deeper understanding on the cytoplasmic inheritance of complex traits.…”

Section: Traitssupporting

confidence: 80%

“…The main argument is the difficulty for deriving direct and maternal effects allowing the correct formation of covariance structure (Meyer, 1992), besides the confused interpretation on animal selection caused by the negative genetic correlation between these effects, mainly pre-weaning traits. Estimates of negative correlations between direct and maternal effects have been reported by Eler et al (2000), Cabrera et al (2001), Ferreira et al (2011 for Nellore cattle. However, there is no consensus on the incorporation of direct and maternal genetic covariance in the statistical models for genetic evaluation in Nellore cattle.…”

Section: Introductionmentioning

confidence: 85%

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Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

et al. 2016

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ABSTRACT.We evaluated the impact of cytoplasmic lineage effects (Lc) for growth traits on genetic evaluation, including the genetic covariance between direct and maternal effects (s am ). Pedigree data from 496,190 Nellore animals and observations on birth weight (BW, N = 243,391), weaning weight (WW, N = 431,681), and post-weaning weight gain adjusted to 345 days (PWG, N = 172,131) were analyzed. Four univariate models were used to obtain estimates of (co)variance components using the restricted maximum likelihood method in the BLUPF90 program. Model 1 included Lc and s am . Model 2 included Lc and s am was set to zero. Model 3 did not include Lc. Model 4 did not include Lc and s am was set to zero. These models considered the effects of the Lc as random. Phenotypic variance obtained through cytoplasmic lineage effects was determined for all traits, ranging from 0.07 to 0.15, 0.15 to 0.03, and 0.05 to 0.03% for BW, WW, and PWG, respectively, for models 1 and 2. Correlations between direct and maternal genetic components were positive for WW and negative for BW and PWG. No differences were observed for genetic parameter estimates or animal ranking with the inclusion of s am . For BW, the likelihood ratio suggested that model 1 best fits the data, while model 4 was the most appropriate for WW and PWG. Thus, these models are recommended for genetic evaluations. Despite the low magnitude of cytoplasmic lineages, this effect could predict breeding value and improve the selection of animals for BW in this Nellore population.

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Section: Traitssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 85%

Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

et al. 2016

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“…Antagonism between the effects of an individual's genes for growth and those of its dam for a maternal contribution may also be due to natural selection for an intermediate optimum (Tosh and Kemp, 1994). As reported by Heydarpour et al (2008) and Ferreira et al (2011), the number of offspring per dam may have increased the dependence between maternal parameters, although other factors such as the number of dams with records also interfere with these estimates.…”

Section: Discussionmentioning

confidence: 84%

Research Article Bayesian analyses of genetic parameters for growth traits in Nellore cattle raised on pasture.

Lopes¹,

Ferreira

Lôbo³

et al. 2017

Genet. Mol. Res.

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This study was carried out to investigate (co)variance components and genetic parameters for growth traits in beef cattle using a multi-trait model by Bayesian methods. Genetic and residual (co)variances and parameters were estimated for weights at standard ages of 120 (W120), 210 (W210), 365 (W365), and 450 days (W450), and for pre- and post-weaning daily weight gain (preWWG and postWWG) in Nellore cattle. Data were collected over 16 years (1993-2009), and all animals were raised on pasture in eight farms in the North of Brazil that participate in the National Association of Breeders and Researchers. Analyses were run by the Bayesian approach using Gibbs sampler. Additive direct heritabilities for W120, W210, W365, and W450 and for preWWG and postWWG were 0.28 ± 0.013, 0.32 ± 0.002, 0.31 ± 0.002, 0.50 ± 0.026, 0.61 ± 0.047, and 0.79 ± 0.055, respectively. The estimates of maternal heritability were 0.32 ± 0.012, 0.29 ± 0.004, 0.30 ± 0.005, 0.25 ± 0.015, 0.23 ± 0.017, and 0.22 ± 0.016, respectively, for W120, W210, W365, and W450 and for preWWG and postWWG. The estimates of genetic direct additive correlation among all traits were positive and ranged from 0.25 ± 0.03 (preWWG and postWWG) to 0.99 ± 0.00 (W210 and preWWG). The moderate to high estimates of heritability and genetic correlation for weights and daily weight gains at different ages is suggestive of genetic improvement in these traits by selection at an appropriate age. Maternal genetic effects seemed to be significant across the traits. When the focus is on direct and maternal effects, W210 seems to be a good criterium for the selection of Nellore cattle considering the importance of this breed as a major breed of beef cattle not only in Northern Brazil but all regions covered by tropical pastures. As in this study the genetic correlations among all traits were high, the selection based on weaning weight might be a good choice because at this age there are two important effects (maternal and direct genetic effects). In contrast, W120 should be preferred when the objective is improving the maternal ability of the dams. Furthermore, selection for postWWG can be used if the animals show both heavier weaning weights and high growth rate after weaning because it is possible to shorten the time between weaning and slaughter based on weaning weight, postWWG, and desired weight at the time of slaughter.

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“…Esse antagonismo genético tem sido levado em conta nas avaliações genéticas de muitas raças de bovinos de corte, por causa da recomendação de se considerar valor zero para a correlação genética entre os efeitos direto e maternal. Na realidade, a recomendação se baseia, principalmente, na dificuldade da separação dos diferentes efeitos e suas correlações sobre o desempenho fenotípico, presente em dados de campo (FERREIRA et al, 2011).…”

Section: Resultsunclassified

Efeitos Genéticos E Ambientais Sobre as Características Produtivas Em Rebanho Nelore Criado Na Região Norte Do Estado Do Tocantins

Nepomuceno¹,

Andrade²,

Lopes³

et al. 2012

Rev. Acad. Ciênc. Anim.

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Objetivou-se estudar a influência de efeitos genéticos e ambientais sobre as características de peso aos 205dias (P205), peso aos 365 dias (P365) e peso aos 550 dias (P550), em rebanho da raça Nelore criado em Araguaína (TO). As médias obtidas para P205, P365 e P550 encontram-se dentro dos limites estabelecidos em outras regiões do Brasil. As fontes de variações apresentaram efeito significativo (p < 0,05) sobre os pesos estudados. Os efeitos de sexo, ano, idade da vaca e mês de nascimento são importantes fatores não genéticos que influenciam os pesos pré-desmama e pós-desmama de bovinos da raça Nelore. As estimativas dos coeficientes de herdabilidades foram de média a alta magnitude, resultando em boa variabilidade genética dentro do rebanho, bem como a possibilidade de seleção para tais características.

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Efeitos Da Inclusão Ou Não Da Covariância Genética Direta-Maternal No Modelo E Dos Valores Reais Das (Co)variâncias Sobre Suas Estimativas Para Peso À Desmama Em Bovinos De Corte

Cited by 3 publications

References 14 publications

Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

Research Article Bayesian analyses of genetic parameters for growth traits in Nellore cattle raised on pasture.

Efeitos Genéticos E Ambientais Sobre as Características Produtivas Em Rebanho Nelore Criado Na Região Norte Do Estado Do Tocantins

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