Fatores ambientais e genéticos que influenciam o desenvolvimento ponderal até o desmame de animais Nelore criados no Nordeste do Brasil

Biffani, Stefano; Filho, Raimundo Martins; Martini, Andrea; Bozzi, Rıccardo; Lima, Francisco de Assis Melo

doi:10.1590/s1516-35981999000400006

Cited by 6 publications

(2 citation statements)

References 11 publications

(9 reference statements)

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“…As herdabilidades para P365 e P550 foram de alta magnitude, com valores iguais a 0,51 e 0,41, respectivamente (Tabela 2). Estas estimativas assemelham-se aos valores médios encontrados na literatura, corroborando resultados obtidos por Biffani et al (1999) no Nordeste do Brasil (0,56 e 0,64); e são superiores ao reportado por Frizzas et al (2009), os quais estimaram herdabilidades de 0,25 tanto para P365 quanto para P550.…”

Section: Resultsunclassified

Tendência genética para pesos padronizados aos 205, 365 e 550 dias de idade de bovinos Nelore da região norte do Brasil

Santos

Lopes

Marques³

et al. 2012

Acta Sci. Anim. Sci.

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Pesquisas efetivas que avaliam a eficiência dos rebanhos bovinos na região Norte do Brasil são insipientes. Por isso, objetivou-se avaliar as mudanças genéticas aditivas diretas e maternais dos pesos padronizados para 205 (P205), 365 (P365) e 550 (P550) dias de idade, de animais da raça Nelore, criados a pasto, nascidos entre 1997 e 2007 na região Norte do Brasil. As estimativas dos componentes de (co)variâncias utilizadas no cálculo dos valores genéticos foram obtidas pelo método de máxima verossimilhança restrita livre de derivadas (REML), usando o aplicativo MTDFREML. As tendências genéticas dos efeitos genéticos direto e maternal foram estimadas pela regressão, ponderada, das médias anuais dos valores genéticos dos animais. As estimativas das herdabilidade para P205, P365 e P550 foram 0,33; 0,51 e 0,41, com ganhos genéticos de 0,494, 1,229 e 1,500 kg ano-1 , respectivamente. Em virtude da variação genética existente, verificou-se que a seleção do rebanho na região Norte do Brasil tem enfatizado principalmente a seleção para peso pós-desmama, ressaltando-se que a seleção para estes pesos pode gerar ao longo dos anos, aumento nos custos de produção, da idade ao abate e acabamento dos animais, havendo assim, necessidade de seleção mais criteriosa para estas características. Palavras-chave: (co)variância, ganho genético, herdabilidade, zebu. Genetic trend for adjusted weight at 205, 365 and 550 days of age of Nellore cattle from Northern Brazil ABSTRACT. Effective researches assessing the efficiency of cattle herds in Northern Brazil are incipient. This study aimed to evaluate the direct additive and maternal genetic trends of weights adjusted to 205 (P205), 365 (P365) and 550 (550) days of age in Nellore animals raised on pasture, born between 1997 and 2007, from Northern Brazil. Estimative of (co)variance components used in the prediction of breeding values were obtained by derivative-free restricted maximum likelihood method (REML) using the MTDFREML program. The genetic trends of direct and maternal genetic effects were obtained by the regression of the annual average of predicted breeding values. The heritability estimates for P205, P365 and P550 were 0.33, 0.51 and 0.41, with genetic gain of 0.494, 1.229 and 1.500 kg year-1 , respectively. The genetic variance evidenced that the selection of cattle herds from Northern Brazil has mainly emphasized the selection for post-weaning. Along years, this selection for these weights can generate increase in production costs, of age at slaughter, and dressing of these animals. Therefore, there are need more judicious selection for these characteristics.

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Section: Resultsunclassified

Tendência genética para pesos padronizados aos 205, 365 e 550 dias de idade de bovinos Nelore da região norte do Brasil

Santos

Lopes

Marques³

et al. 2012

Acta Sci. Anim. Sci.

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“…Particularly for the WW trait, some studies in which models considering factors common to those of this work were evaluated, found R 2 values of 46% (Biffani, Martins, Martini, Bozzi, & Lima, 1999), 64% (Silveira et al, 2004), and 42% (Ossa et al, 2004). In the current work, for the WW characteristic with the inclusion in the CG model, it had an R 2 of 59%, which implies a 21% increase in the R 2 concerning model 12, highlighting the effect of the inclusion of the CG as a source of important variation in the model.…”

Section: Resultsmentioning

confidence: 76%

Best linear model to explain variability in the growth in Blanco Orejinegro cattle and effect of the serological status for bovine viral diarrhea and bovine leukosis

Saldarriaga-Saldarriaga

Herrera

Londoño-Gil

et al. 2020

SCA

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The cattle breed Blanco Orejinegro (BON) is an important animal genetic resource in Colombia that needs to be studied to identify its productive benefits for Colombian livestock. The aim of this work was to establish the best linear model that explains the variability for birth weight, weaning weight and yearling weight, and estimate the effect of the serological status for Bovine Viral Diarrhea (BVD) and Bovine Leukosis (BL) in BON cattle in Colombia. The information on animal weighings belonging to 14 BON cattle herds, was collected and cleansed. Using the least squares method, 12 linear models were evaluated including as fixed effects, factors such as herd, sex, weighing month, birth order, season (rainy or dry), birth year, and contemporary group (formed by the concatenation of the factors herd, sex, and birth year). The weighing age was included as a covariate for weaning and yearling weights. For the selection of a model that best describes each parameter, the criteria for choosing models, such as Akaike information criterion (AIC), Bayesian Information criterion (BIC), coefficient of determination (R2), and the sum of squares of the error (SSE), were considered. The model that included the contemporary group showed the best fit, being also the best to describe the three parameters evaluated, since, of the four criteria considered for its evaluation, AIC and SSE showed the lowest values and the highest R2. With this model, weight predictions with higher precision were able to be performed. Employing indirect ELISA screening tests of blood plasma, the serological status of each animal was estimated for BVD and BL viral infections. The serological status of these two viral infections was included in the best-fit model. There was no significant effect of the serological status on the parameters evaluated, so there are indications that animals that came in contact with the virus were not affected during growth.

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Meta-análise de parâmetros genéticos de características de crescimento em bovinos de corte sob enfoques clássico e Bayesiano.

Giannotti¹

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Fatores ambientais e genéticos que influenciam o desenvolvimento ponderal até o desmame de animais Nelore criados no Nordeste do Brasil

Cited by 6 publications

References 11 publications

Tendência genética para pesos padronizados aos 205, 365 e 550 dias de idade de bovinos Nelore da região norte do Brasil

Tendência genética para pesos padronizados aos 205, 365 e 550 dias de idade de bovinos Nelore da região norte do Brasil

Best linear model to explain variability in the growth in Blanco Orejinegro cattle and effect of the serological status for bovine viral diarrhea and bovine leukosis

Meta-análise de parâmetros genéticos de características de crescimento em bovinos de corte sob enfoques clássico e Bayesiano.

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