Genetic evaluation models for post-weaning weight gain in a multibreed Angus-Nelore population

Prestes, Alan Miranda; Oliveira, Maurício Morgado de; Mello, Fernanda Cristina Breda; Rorato, Paulo Roberto Nogara; Lopes, Jader Silva; Feltes, Giovani Luis; Bravo, André Padilha

doi:10.1590/s1678-3921.pab2019.v54.00694

Cited by 3 publications

(4 citation statements)

References 27 publications

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“…The Spearman's rank-order correlation between the genetics values predicted by the TAM(GHE) and CAM+S(GHE) models, considering all sires in the population, was 0.94. Similar results were reported by PRESTES et al(2019) andOLIVEIRA et al (2010) for post-weaning weight gain in Angus/Nellore populations.…”

Section: Resultssupporting

confidence: 91%

“…When testing crossbred models involving the Angus and Nellore breeds, some studies reported superiority of the model without segregation for post-weaning weight gain (OLIVEIRA et al, 2010;PRESTES et al, 2019). However, BIRCHMEIER et al (2002 evaluated Angus-Hereford and Nellore-Hereford populations and found that 11.4% to 16% of the total additive variance for weight at birth was explained by the variance of segregation in F2; they reported that genetic evaluations using the covariance crossbred theory require the estimate of the variance of segregation.…”

Section: Resultsmentioning

confidence: 99%

“…The lowest rank-order correlations reported (top 20% and 30% sires) can be explained by the lower selection pression on these animals. According to PRESTES et al (2019), the lower the selection intensity, the higher the genetic variability. The genetics values predicted by the TAM(GHE) model were higher than those predicted by the CAM+S(GHE), probably because the TAM(GHE) model does not consider variances of breeds separately, as well as variance of segregation (Figure 2).…”

Section: Resultsmentioning

confidence: 99%

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Genetic evaluation models for resistance to ticks in a crossbred Angus-Nellore population

et al. 2021

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This research identified the animal model that best describes the genetic and residual variations for tick counts in yearlings from a crossbred Angus-Nellore population of 6,951 animals that are progenies of 382 bulls and 6,198 cows. Genetic values were predicted by the Bayesian inference methodology. The models tested were: Traditional Animal, and Crossbred Animal with and without segregation, considering residual homoscedastic and heteroscedastic variances. The criteria of choice were the number of parameters, deviance information, and predictive order, which indicated the best fitfor the Traditional Animal model and Crossbred Animal model (with segregation), both with residual heteroscedastic Gaussian variance. The mean values of fixed genetic effects were positive and similar in the both models, indicating that animals with higher proportion of the Angus breed had greater infestation, and the Nellore breed was an important addition for resistance to ticks. The estimated genetic variation by the heteroscedastic Gaussian Animal model for the Nellore breed was 4.54-fold higher than that estimated for the Angus breed. The estimates of heritability of the different genetic groups ranged from 0.12 to 0.15 and from 0.01 to 0.35, respectively, for the Traditional Animal model and for the heteroscedastic Gaussian crossbred model. The Spearman’s rank-order correlation for the predicted genetic values was 0.94, considering all sires. However, when considering the top 10%, 20%, and 30% sires, differences in ranking were more evident (0.28 to 0.67). The Crossbred Animal model with segregation and heterogeneous residual variances was the most appropriate for genetic evaluation of tick counts on animals from Angus-Nellore crossings.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Genetic evaluation models for resistance to ticks in a crossbred Angus-Nellore population

et al. 2021

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“…Moreover, a meta-analysis showed that direct and maternal breed and heterosis effect estimated using crossbreeding study data can supplement the direct prediction in a multibreed evaluation (Williams et al, 2013). Although the multiple-breed evaluation can be an alternative to evaluate YW, to better understand their genetic architecture in the evaluated composite population, this analysis requires a much larger number of variance components to be estimated and it is computationally more complex, besides presenting multicollinearity problems, and thus may be cumbersome for practical applications (Cardoso and Tempelman, 2004;Bueno et al, 2012;Prestes et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Estimation of genetic parameters for weaning and yearling weights in a composite population used to form the Purunã breed

Otto¹,

Santos²,

Perotto³

et al. 2021

Revista Brasileira De Zootecnia

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We aimed to evaluate the effects of sex and the linear and quadratic components of age of dam at calving, as well as apply a mixed model including maternal effect for the genetic evaluation of weaning (WW) and yearling (YW) weights. The phenotypic database was composed by Charolais, Caracu, Aberdeen Angus, and Canchim purebred and crossbred animals. Single-trait analyses were performed using models that included the maternal effect for WW and YW traits, and a model ignoring this effect on YW (YWNM). The Deviance Information Criterion (DIC), model posterior probabilities (MPP), accuracy of breeding values (ACC), and Spearman's rank correlation were applied to compare the models including and ignoring the maternal effect on YW. Sex and age of dam at calving had significant effects on WW and YW. The direct heritability estimates were 0.21±0.03 and 0.05±0.02, and the maternal heritabilities were 0.11±0.02 and 0.02±0.01 for WW and YW, respectively. The heritabilities estimated for YW may have been influenced by the several genetic groups in the population and by used conventional animal model, which may not have been the better fit model to evaluate YW in this population. The DIC, MPP, and ACC values indicated that YW outperformed the YWNM model, but the rank correlation and percentages of individuals selected in common suggested that the best animals would be selected independently of the model chosen.

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Genetic parameters for mouth size and their influence on growth traits in pasture-raised Nelore cattle

Domínguez-Castaño

Maiorano

Lopes

et al. 2023

Journal of Animal Science

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Evaluating traits that allow breeders to increase production efficiency in beef production systems is important. The mouth size score is a trait easily measured and implemented by breeders. Bite size is related to mouth size in beef cattle and is a determinant of daily feed intake of pasture-raised animals, influencing their growth. The aim of this study was to estimate genetic parameters for mouth size (MS), weaning weight (WW) and postweaning weight gain (PWG) of Nelore cattle and to evaluate the influence of the interaction between MS and WW on PWG. Phenotypic records of 134,282 Nelore animals born between 1995 and 2019 were used. Variance components were estimated using multi-trait animal model with the Bayesian method. The model included the contemporary group as fixed effect, age at measurement of the trait as linear covariate, and direct additive genetic and residual effects as random effects. For WW, random maternal and maternal permanent environmental effects were added to the model. A Bayesian approach was used to analyze the interaction between WW clusters and MS. The heritability estimates were 0.24, 0.15 and 0.23 for MS, WW and PWG, respectively. The genetic correlation between variables studied ranged from 0.24 to 0.46. The results suggest that animals with a larger mouth tend to have greater PWG, demonstrating the positive influence of MS score on the postweaning performance of cattle. The direct heritability estimates confirm the possibility of selecting animals for the traits studied.

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Genetic evaluation models for post-weaning weight gain in a multibreed Angus-Nelore population

Cited by 3 publications

References 27 publications

Genetic evaluation models for resistance to ticks in a crossbred Angus-Nellore population

Genetic evaluation models for resistance to ticks in a crossbred Angus-Nellore population

Estimation of genetic parameters for weaning and yearling weights in a composite population used to form the Purunã breed

Genetic parameters for mouth size and their influence on growth traits in pasture-raised Nelore cattle

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