Parâmetros genéticos para características de crescimento e reprodutivas em bovinos Nelore no Brasil

Barbosa, Artur Felipe Santos; Carneiro, Paulo L. S.; Rezende, Marcos Paulo Gonçalves de; Ramos, I.O.; Martin-Filho, R.; Malhado, C. H. M.

doi:10.21071/az.v66i255.2523

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…Values of posterior heritability means obtained in this study are consistent with values observed by other authors. Heritability estimates in cattle for weaning weight ranged from 0.11 to 0.25 (Moreira et al, 2015;Santos et al, 2019;Barbosa et al, 2017), from 0.16 to 0.44 for the yearling weight (Moreira et al, 2015;Souza et al 2018;Santos et al, 2019;Barbosa et al, 2017), from 0.17 to 0.44 for post-yearling weight (Moreira et al, 2015;Souza et al, 2018;Santos et al, 2019;Barbosa et al, 2017), and from 0.20 to 0.26 for post-weaning weight gain (Duitama et al, 2015;Santana et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

The impact of heterogeneity of variances on the genetic evaluation of performance traits in Nellore cattle

Menezes¹,

Araújo²,

Novo³

et al. 2022

Revista Brasileira De Zootecnia

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The objective was to evaluate the existence of heterogeneity of variances and its impact on the genetic evaluation of ponderal performance in sires of the Nellore breed. We used records of adjusted body weights at 210 (W210), 365 (W365), and 450 (W450) days of age. Both W365 and W450 were combined by principal component analyses using the first component (PC). Average daily gain (ADG) was obtained by difference between W450 and W210. The classes of standard deviations (SD) for W210, PC, and ADG were obtained by the standardization of means of herd-year means subclasses, with positive values composing the high SD and values equal and less than zero composing the SD. The model included the fixed effects of contemporary group and age at calving as a covariate, random genetic additive, and maternal genetic (except for PC) effects, and the permanent maternal environment. Variance components were obtained by Gibbs sampling. Posterior means of heritability in analyses without considering heterogeneity of variances ranged from 0.15±0.01 to 0.31±0.01. Posterior means of genetic correlations between the two classes of SD for W210, PC, and ADG were equal to 0.85±0.04, 0.83±0.03, and 0.71±0.08, respectively. Spearman correlation to breeding values of sires for ADG as the selection intensity increased in them, and the correlations between breeding values in general analyses were more correlated with those predicted in the high DP. Therefore, when there is a higher selection intensity on the sires only for the ADG criterion, there is a significant presence of the heterogeneity of variances and impact on the genetic evaluation of the sires. Thus, for ADG, the predictions of breeding values obtained by the genetic evaluation model in which the heterogeneity of variances are not considered are more weighted by the class of greater heterogeneity.

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Section: Discussionmentioning

confidence: 99%

The impact of heterogeneity of variances on the genetic evaluation of performance traits in Nellore cattle

Menezes¹,

Araújo²,

Novo³

et al. 2022

Revista Brasileira De Zootecnia

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“…Because of this importance, genetic improvement programs related to growth traits in beef cattle have been developed throughout the country (Santana et al, 2017), aiming at increasing productive and reproductive potential. Estimates of genetic parameters for growth traits in beef cattle are indicators of the response to genetic improvement (Barbosa et al, 2017), allowing classification and selection of the best individuals to be parents in the next generations. One aspect to consider in this context is that several authors have reported on the estimates of genetic parameters in populations of Nelore in different regions of Brazil (Passafaro et al, 2016;Barbosa et al, 2017;Souza et al, 2018;Pereira, 2021) and showed the existence of genetic variability, which allows for genetic progress through selection.…”

Section: Introductionmentioning

confidence: 99%

Genetic parameters and trends of growth traits in Nelore cattle raised in the Northern region of Brazil

Rodrigues

Espigolan

Ferraz

et al. 2022

Braz. J. Vet. Res. Anim. Sci.

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The objective of this study was to estimate (co)variances and genetic parameters and to predict genetic trends for weight at 120 (W120), 210 (W210), 365 (W365), and 450 (W450) days of age in Nelore cattle raised in the northern region of Brazil. The database comprised records of 30,387 animals born between 2000 and 2013 in the Brazilian North. Estimates were calculated by the Restricted Maximum Likelihood (REML) method, in single- and multi-trait analyses in an animal model. Heritability as obtained using single- and multi-trait models for W120 (0.22 and 0.31), W210 (0.20 and 0.34), W365 (0.51 and 0.51), and W450 (0.49 and 0.51) indicated moderate to high magnitudes, with the possibility of genetic selection and incorporation into the herd. Genetic correlations between growth traits were favorable, ranging from 0.78 to 0.96. Genetic trends for W120 and W210 varied largely, from -0.31 to 4.68 and -0.53 to 7.62 kg/year, respectively. Smaller fluctuations were observed in genetic trends for W365 and W450, which ranged from -1.08 to 10.90 and -1.29 to 12.51 kg/year, respectively. Selection for W365 and W450 proved to be the criterion of choice for Nelore herds raised in the region; however, it may compromise adult performance because of higher costs and time for production. A thorough analysis of mattings is recommended to allow the selection of earlier-developing animals.

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“…Ademais, outra justificativa para utilização desta característica é especialmente por serem de fácil mensuração (Silva et al 2012) e por apresentar herdabilidades moderadas permitindo possíveis ganhos genéticos ao longo das gerações. As estimativas dos parâmetros genéticos para as características de crescimento em bovinos de corte são indicadoras da resposta ao melhoramento genético a ser alcançado (Barbosa et al 2017), permitindo classificar e selecionar os melhores indivíduos para serem pais nas próximas gerações.…”

Section: Introductionunclassified

Estimação De Parâmetros Genéticos Para Características De Crescimento Em Bovinos Nelore Mocho Da Região Norte Do Brasil

Evangelista¹,

Cavalcante²,

Malhado³

et al. 2021

Zootecnia: Pesquisa E Práticas Contemporâneas - Volume 2

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O objetivo deste trabalho foi estimar os parâmetros genéticos para as características peso ao desmame (P205), ao ano (P365) e sobreano (P550) de bovinos Nelore Mocho, criados na região Norte do Brasil. Foram utilizados 39.737 registros de peso pertencentes a 8.530 animais. Os parâmetros genéticos foram obtidos utilizando-se o método da máxima verossimilhança restrita (REML) sob o modelo animal, usando aplicativo computacional WOMBAT. O modelo empregado incluiu efeitos fixos de grupo de contemporâneos (sexo, fazenda, ano e estação de nascimento do animal) e idade da vaca ao parto como covariáveis (efeito quadrático), além de efeitos aleatórios genético aditivo direto, genético materno e ambiente permanente materno, adotando-se o modelo multicaracteristicas. Os coeficientes de herdabilidade direta estimados para as características estudadas foram de média a alta magnitude, variando de 0,32 (P550) a 0,50(P205), mostrando alta variabilidade genética e potencial de ganhos considerável utilizando essas características para a seleção. A herdabilidade materna foi de baixa magnitude, variando de 0,07 (P550) a 0,09 (P205) indicando diminuição do efeito materno ao longo do crescimento do animal. As correlações genéticas entre as características foram altas, positivos e superiores a 0,84, evidenciando alta associação entre as características, podendo-se obter ganhos genéticos via resposta correlacionada para P365 e P550 ao selecionar o P205. Entretanto, observam-se indicativas de que as características avaliadas são passíveis de seleção para o melhoramento genético da raça Nelore Mocho criados na região Norte do Brasil.

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Parâmetros genéticos para características de crescimento e reprodutivas em bovinos Nelore no Brasil

Cited by 8 publications

References 10 publications

The impact of heterogeneity of variances on the genetic evaluation of performance traits in Nellore cattle

The impact of heterogeneity of variances on the genetic evaluation of performance traits in Nellore cattle

Genetic parameters and trends of growth traits in Nelore cattle raised in the Northern region of Brazil

Estimação De Parâmetros Genéticos Para Características De Crescimento Em Bovinos Nelore Mocho Da Região Norte Do Brasil

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