Tendência genética para características relacionadas à velocidade de crescimento em bovinos Nelore da região norte do Brasil

Lopes, Fernando Brito; Santos, Geneíldes Cristina de Jesus; Marques, Ednira Gleida; Silva, Marcelo Corrêa da; Ferreira, Jorge Luís

doi:10.1590/s1806-66902012000200020

Cited by 8 publications

(7 citation statements)

References 16 publications

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“…The greatest weight gain interval is between calving and weaning [9], [30] and a clear decrease in growing rates occurs after one year of age, when the fattening and carcass finishing stages are more significant [8], [31], [32]. Following this profile, all breeding programs in Brazil are designed to consider only adjusted weights and specific standard ages.…”

Section: Discussionmentioning

confidence: 99%

Genetic Analysis of Growth Traits in Polled Nellore Cattle Raised on Pasture in Tropical Region Using Bayesian Approaches

et al. 2013

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Components of (co)variance and genetic parameters were estimated for adjusted weights at ages 120 (W120), 240 (W240), 365 (W365) and 450 (W450) days of Polled Nellore cattle raised on pasture and born between 1987 and 2010. Analyses were performed using an animal model, considering fixed effects: herd-year-season of birth and calf sex as contemporary groups and the age of cow as a covariate. Gibbs Samplers were used to estimate (co)variance components, genetic parameters and additive genetic effects, which accounted for great proportion of total variation in these traits. High direct heritability estimates for the growth traits were revealed and presented mean 0.43, 0.61, 0.72 and 0.67 for W120, W240, W365 and W450, respectively. Maternal heritabilities were 0.07 and 0.08 for W120 and W240, respectively. Direct additive genetic correlations between the weight at 120, 240, 365 and 450 days old were strong and positive. These estimates ranged from 0.68 to 0.98. Direct-maternal genetic correlations were negative for W120 and W240. The estimates ranged from −0.31 to −0.54. Estimates of maternal heritability ranged from 0.056 to 0.092 for W120 and from 0.064 to 0.096 for W240. This study showed that genetic progress is possible for the growth traits we studied, which is a novel and favorable indicator for an upcoming and promising Polled Zebu breed in Tropical regions. Maternal effects influenced the performance of weight at 120 and 240 days old. These effects should be taken into account in genetic analyses of growth traits by fitting them as a genetic or a permanent environmental effect, or even both. In general, due to a medium-high estimate of environmental (co)variance components, management and feeding conditions for Polled Nellore raised at pasture in tropical regions of Brazil needs improvement and growth performance can be enhanced.

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Section: Discussionmentioning

confidence: 99%

Genetic Analysis of Growth Traits in Polled Nellore Cattle Raised on Pasture in Tropical Region Using Bayesian Approaches

et al. 2013

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“…Among the many available algorithms of this device, the PX-AI algorithm was chosen, because, it combines the PX (parameter expanded) method, which is a variation of the EM (expectation maximization) algorithm, with the AI (average information) algorithm (Meyer, 1997). Eighteen models with Legendre orthogonal polynomials of first to sixth order were used to describe the effects of direct additive genetic and animal permanent environment of the animal.…”

Section: Methodsmentioning

confidence: 99%

Analysis of longitudinal data of Nellore cattle from performance test at pasture using random regression model

et al. 2012

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This study was carried out to estimate (co)variance components and genetic parameters for live weight of Nellore cattle from Performance Test of Young Bulls using random regression models. Data of weights and ages of 925 weaned males was used. The animal model included the fixed effect of contemporary group, age of the animal at weighing as a covariate and as random effects it was considered the effect of additive genetic and permanent environment of the animal. The residue was modeled considering four classes of variances. The models were compared based on the Bayesian information criteria of Akaike and Schwartz. The model polynomial of fourth and sixth order for the direct additive genetic effects and permanent environment of the animal, respectively was the most appropriate to describe the changes in the variances of the weights during the period in which the animals participating in the performance test young bulls. Heritability estimates showed moderate magnitudes and indicated that direct selection will promote improvement of selection criteria adopted. Furthermore, due to high positive correlation between the estimated weights, it was suggested selecting the best animals before at 365 days of age, because it is the period in which the animals have a higher growth rate and thus you can select animals heavier and less delayed.

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“…Several researchers have studied carcass, food intake and growth traits, such as weight at different ages, growth curves and features related to growth rate of Nellore cattle (BOUQUET et al, 2010;HERD;ARCHER;ARTHUR, 2004;HOQUE et al, 2009;LANCASTER et al, 2009;LOPES et al, 2011;LOPES et al, 2012;ROBINSON;ODDY, 2004;SOUZA et al, 2008;SANTOS et al, 2012). However, research to evaluate meat quality, especially tenderness and its relationships with growth and carcass quality traits of Zebu cattle in Brazil, are incipient.…”

Section: Introductionmentioning

confidence: 99%

Quantitative genetic analysis for meat tenderness trait in Polled Nellore cattle

Castro¹,

Magnabosco²,

Sainz³

et al. 2014

Rev. Ciênc. Agron.

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-The aim of the present study was to analyze the interrelationships among the variables and also estimate the genetic correlations between tenderness (WBSF), growth (ILW, FLW and ADG) and carcass (BF, RF and LMA) features. Other purpose was to identify individuals who were more likely to be carriers of favorable genes for tenderness. Growth, carcass and tenderness data from 415 Polled Nellore animals was analyzed. Factor analysis and canonical correlations were used to analyze the phenotypic relationships. The covariance components and genetic parameters were estimated using Gibbs Sampling method. Lack of phenotypical correlations between the WBSF and the other traits were observed. The genetic correlations between WBSF and the other evaluated traits were of a low magnitude, with values of -0.15; -0.18; -0.13; 0.10; -0.12 and 0.18, between WBSF and ILW, FLW, ADG, BF, RF and LMA, respectively. The results support the conclusion that tenderness selection will not affect the selection of other economic traits and vice-versa, but for a better knowledge of the genetic relationships between meat tenderness and other traits for Polled Nellore more studies are required. The heritability estimated for WBSF was of a low magnitude (0.11 ± 0.022). Based on the principle of probability of identical genes by ancestry individuals who were more likely to be carriers of favorable genes for tenderness were identified. Further work will include creation of a segregating population that will serve as experimental material for future gene prospecting and identification research.Key works: Carcass. Shear force. Pedigree.RESUMO -Objetivou-se analisar os inter-relacionamentos entre as variáveis, além de estimar as correlações genéticas entre os grupos de características de maciez (FC), crescimento (PI, PF e GPD) e carcaça (EG, P8 e AOL). Foi proposto também, identificar indivíduos que apresentem alta probabilidade de serem portadores de genes favoráveis à maciez. Analisouse dados de 415 animais Nelore Mocho, filhos de touros representativos das principais linhagens Nelore, avaliados para características de crescimento, carcaça e maciez. Para análises de relacionamentos fenotípicos foram utilizadas análises de fatores e correlações canônicas. Os componentes de variância necessários à obtenção dos parâmetros genéticos foram estimados pelo método da Amostragem de Gibbs. Observou-se ausência de correlações fenotípicas entre FC e as outras características produtivas. As correlações genéticas entre FC e PI, PF, GPD, EG, P8 e AOL foram de baixa magnitude (-0,15; -0,18; -0,13; 0,10; -0,12 e 0,18). A seleção para a maciez não influenciará na seleção de outras características de interesse econômico e vice-versa, porém serão necessários mais estudos para melhor conhecimento sobre as relações genéticas da maciez e outras características produtivas em bovinos Nelore Mocho. A estimativa de herdabilidade para a característica FC foi de baixa magnitude (0,11 ± 0,022). Baseando-se no princípio da probabilidade de genes idênticos por descendê...

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Tendência genética para características relacionadas à velocidade de crescimento em bovinos Nelore da região norte do Brasil

Cited by 8 publications

References 16 publications

Genetic Analysis of Growth Traits in Polled Nellore Cattle Raised on Pasture in Tropical Region Using Bayesian Approaches

Genetic Analysis of Growth Traits in Polled Nellore Cattle Raised on Pasture in Tropical Region Using Bayesian Approaches

Analysis of longitudinal data of Nellore cattle from performance test at pasture using random regression model

Quantitative genetic analysis for meat tenderness trait in Polled Nellore cattle

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