scholarly journals PSXVII-5 Genomic evaluation of genotype by prenatal nutritional environment interaction for growth traits in beef cattle.

2018 ◽  
Vol 96 (suppl_3) ◽  
pp. 147-147
Author(s):  
E Hay ◽  
A Roberts
Keyword(s):  
Beef Cattle ◽  
Growth Traits ◽  
Environment Interaction ◽  
Genomic Evaluation ◽  
Nutritional Environment

Genetic correlation between growth and reproductive performance of beef females depends on environment

2018 ◽  
Vol 58 (7) ◽  
pp. 1201 ◽  
Author(s):  
Mário L. Santana Jr ◽  
Joanir P. Eler ◽  
Annaiza B. Bignardi ◽  
Arione A. Boligon ◽  
José B. S. Ferraz
Keyword(s):  
Beef Cattle ◽  
Genetic Correlation ◽  
Reproductive Performance ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Random Regression ◽  
Tropical Region ◽  
Correlated Response ◽  
Heterogeneous Environments ◽  
Environment Interaction

In tropical production systems, beef cattle are raised in highly heterogeneous environments. Heterogeneity is, therefore, expected to exist in the (co)variance components for traits of economic interest in different production environments. The main objective of the present study was to estimate genetic correlations between growth traits and reproductive performance of beef females, depending on the environment. The present study was conducted in the tropical region of Brazil, applying a multiple-trait random regression animal model to field records of heifer pregnancy (HP), hip height, bodyweight at ~18 months of age (BW18) and postweaning weight gain (PWG) from 20 893 Nelore females. As evidence of genotype by environment interaction (G × E), heterogeneity of genetic variance across environments was observed mainly for HP, PWG and BW18. Moreover, the estimates of genetic correlation within these traits reached values lower than unity on the environmental gradient. The genetic correlation among growth traits tended to be stronger in favourable environments, a fact that should favour correlated responses under these conditions. In contrast, the genetic correlations between growth traits and HP tended to become weaker and even exhibited little evidence of antagonism in more favourable environments. On the basis of these findings, selection for higher growth in extreme favourable environments should result in little or no damage to HP as a correlated response. All these results lead us to believe that the G × E is an important factor to be considered in genetic evaluations of beef cattle raised in tropical environments.

scholarly journals Estimating dominance genetic variances for growth traits in American Angus males using genomic models

2019 ◽  
Vol 98 (1) ◽  
Author(s):  
Carolina A Garcia-Baccino ◽  
Daniela A L Lourenco ◽  
Stephen Miller ◽  
Rodolfo J C Cantet ◽  
Zulma G Vitezica
Keyword(s):  
Genetic Variation ◽  
Beef Cattle ◽  
Variance Components ◽  
Growth Traits ◽  
Ratio Test ◽  
Genomic Evaluation ◽  
Male Population ◽  
Genomic Relationships ◽  
Nonadditive Effects ◽  
Genomic Model

Abstract Estimates of dominance variance for growth traits in beef cattle based on pedigree data vary considerably across studies, and the proportion of genetic variance explained by dominance deviations remains largely unknown. The potential benefits of including nonadditive genetic effects in the genomic model combined with the increasing availability of large genomic data sets have recently renewed the interest in including nonadditive genetic effects in genomic evaluation models. The availability of genomic information enables the computation of covariance matrices of dominant genomic relationships among animals, similar to matrices of additive genomic relationships, and in a more straightforward manner than the pedigree-based dominance relationship matrix. Data from 19,357 genotyped American Angus males were used to estimate additive and dominant variance components for 3 growth traits: birth weight, weaning weight, and postweaning gain, and to evaluate the benefit of including dominance effects in beef cattle genomic evaluations. Variance components were estimated using 2 models: the first one included only additive effects (MG) and the second one included both additive and dominance effects (MGD). The dominance deviation variance ranged from 3% to 8% of the additive variance for all 3 traits. Gibbs sampling and REML estimates showed good concordance. Goodness of fit of the models was assessed by a likelihood ratio test. For all traits, MG fitted the data as well as MGD as assessed either by the likelihood ratio test or by the Akaike information criterion. Predictive ability of both models was assessed by cross-validation and did not improve when including dominance effects in the model. There was little evidence of nonadditive genetic variation for growth traits in the American Angus male population as only a small proportion of genetic variation was explained by nonadditive effects. A genomic model including the dominance effect did not improve the model fit. Consequently, including nonadditive effects in the genomic evaluation model is not beneficial for growth traits in the American Angus male population.

scholarly journals Trends in genetic diversity and the effect of inbreeding in American Angus cattle under genomic selection

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Emmanuel A. Lozada-Soto ◽  
Christian Maltecca ◽  
Duc Lu ◽  
Stephen Miller ◽  
John B. Cole ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Beef Cattle ◽  
Genomic Selection ◽  
Inbreeding Depression ◽  
Growth Traits ◽  
Effective Population ◽  
Angus Cattle ◽  
Genomic Inbreeding ◽  
Chromosome Segments ◽  
The Impact

Abstract Background While the adoption of genomic evaluations in livestock has increased genetic gain rates, its effects on genetic diversity and accumulation of inbreeding have raised concerns in cattle populations. Increased inbreeding may affect fitness and decrease the mean performance for economically important traits, such as fertility and growth in beef cattle, with the age of inbreeding having a possible effect on the magnitude of inbreeding depression. The purpose of this study was to determine changes in genetic diversity as a result of the implementation of genomic selection in Angus cattle and quantify potential inbreeding depression effects of total pedigree and genomic inbreeding, and also to investigate the impact of recent and ancient inbreeding. Results We found that the yearly rate of inbreeding accumulation remained similar in sires and decreased significantly in dams since the implementation of genomic selection. Other measures such as effective population size and the effective number of chromosome segments show little evidence of a detrimental effect of using genomic selection strategies on the genetic diversity of beef cattle. We also quantified pedigree and genomic inbreeding depression for fertility and growth. While inbreeding did not affect fertility, an increase in pedigree or genomic inbreeding was associated with decreased birth weight, weaning weight, and post-weaning gain in both sexes. We also measured the impact of the age of inbreeding and found that recent inbreeding had a larger depressive effect on growth than ancient inbreeding. Conclusions In this study, we sought to quantify and understand the possible consequences of genomic selection on the genetic diversity of American Angus cattle. In both sires and dams, we found that, generally, genomic selection resulted in decreased rates of pedigree and genomic inbreeding accumulation and increased or sustained effective population sizes and number of independently segregating chromosome segments. We also found significant depressive effects of inbreeding accumulation on economically important growth traits, particularly with genomic and recent inbreeding.

scholarly journals Genotype by environment interaction on growth and carcass traits in beef cattle in the tropics

2010 ◽  
Vol 1 (2) ◽  
pp. 372-373 ◽  
Author(s):  
Fabrizio Assenza ◽  
Alberto Menendez Buxadera ◽  
Jean-Luc Gourdine ◽  
Alain Farant ◽  
Bruno Bocage ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Carcass Traits ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Genotype By Environment ◽  
The Tropics
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