Genetic relationship between growth and reproductive traits in Nellore cattle

Júnior, Mário Luiz Santana; Eler, Joanir Pereira; Ferraz, José Bento Sterman; Mattos, E. C.

doi:10.1017/s1751731111001856

Cited by 48 publications

(35 citation statements)

References 28 publications

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“…Genetic correlations among the reproductive traits STAY, NC53 and HR were similar and superior compared with those estimated between SC and these traits. Genetic correlation between STAY and SC (0.12 ± 0.058) was similar to that reported by Santana et al (2012), 0.17. These authors suggested that there is no antagonism between SC and STAY; in other words, selection on one trait would produce little or no effect on other.…”

Section: Resultssupporting

confidence: 87%

Genetic relationship among reproductive traits in Nellore cattle

Guarini¹,

Neves²,

Schenkel

et al. 2015

Animal

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In order to achieve improvements in production efficiency in livestock, herds of high sexual precocity and good fertility are needed. These traits increase the availability of animals in herd, either for sale or selection, allowing both greater selective intensity and greater genetic progress. This study aimed at estimating genetic parameters for reproductive traits measured directly in females in order to verify whether they could be used as selection criteria for genetic improvement in Nellore cows, as well as estimating the genetic relationship among these traits and scrotal circumference (SC), the traditional selection criterion for sexual precocity in cattle. In addition to SC, stayability (STAY), number of calvings at 53 months (NC53) and heifers rebreeding (HR) were studied. The (co)variances and genetic parameters were estimated using Bayesian inference. STAY, NC53 and HR were analyzed assuming a threshold model, whereas SC was analyzed with a linear model. Heritability estimated for NC53 was 0.22, and this trait was strongly and positively correlated with STAY, meaning selection for NC53 would improve productive longevity of Nellore cows. Correlations estimated between HR and STAY (≈0.97) and between HR and NC53 (≈0.99) allow an improvement on HR rates if selection was applied to traits related to longevity. Genetic correlations among SC and female reproductive traits were positive but weak, suggesting the need to use reproductive traits directly measured in females in order to obtain greater improvements in sexual precocity and longevity.

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Section: Resultssupporting

confidence: 87%

Genetic relationship among reproductive traits in Nellore cattle

Guarini¹,

Neves²,

Schenkel

et al. 2015

Animal

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“…For SC, mean heritability ranged from 0.15 to 0.23 across the environmental gradient. These estimates are lower than those reported by Vargas et al (1998), Eler et al (2004) and Santana et al (2012b), who found heritabilities ranging from 0.28 to 0.57 for SC of purebred animals. However, similar estimates were obtained by Santana et al (2010) in a study, with part of the present composite cattle raised in the Midwest and Southeast of Brazil.…”

Section: Resultscontrasting

confidence: 74%

Phenotypic plasticity of composite beef cattle performance using reaction norms model with unknown covariate

Júnior

Eler

Cardoso

et al. 2013

Animal

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The objective of the present study was to determine the presence of genotype by environment interaction (G 3 E) and to characterize the phenotypic plasticity of birth weight (BW), weaning weight (WW), postweaning weight gain (PWG) and yearling scrotal circumference (SC) in composite beef cattle using the reaction norms model with unknown covariate. The animals were born between 1995 and 2008 on 33 farms located throughout all Brazilian biomes between latitude 278 and 2318, longitude 2408 and 2638. The contemporary group was chosen as the environmental descriptor, that is, the environmental covariate of the reaction norms. In general, higher estimates of direct heritability were observed in extreme favorable environments. The mean of direct heritability across the environmental gradient ranged from 0.05 to 0.51, 0.09 to 0.43, 0.01 to 0.43 and from 0.12 to 0.26 for BW, WW, PWG and SC, respectively. The variation in direct heritability observed indicates a different response to selection according to the environment in which the animals of the population are evaluated. The correlation between the level and slope of the reaction norm for BW and PWG was high, indicating that animals with higher average breeding values responded better to improvement in environmental conditions, a fact characterizing a scale of G 3 E. Low correlation between the intercept and slope was obtained for WW and SC, implying re-ranking of animals in different environments. Genetic variation exists in the sensitivity of animals to the environment, a fact that permits the selection of more plastic or robust genotypes in the population studied. Thus, the G 3 E is an important factor that should be considered in the genetic evaluation of the present population of composite beef cattle.

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“…For BW, the results obtained for the direct heritability coefficient (h 2 a ) were similar between the four models (Table 5), and similar results were presented by Santana et al (2012) and Regatieri et al (2012). The estimate for h 2 a to PWG, was the same as that reported by Tonussi et al (2015), showing a later response to direct selection.…”

Section: Traitssupporting

confidence: 78%

Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

et al. 2016

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ABSTRACT.We evaluated the impact of cytoplasmic lineage effects (Lc) for growth traits on genetic evaluation, including the genetic covariance between direct and maternal effects (s am ). Pedigree data from 496,190 Nellore animals and observations on birth weight (BW, N = 243,391), weaning weight (WW, N = 431,681), and post-weaning weight gain adjusted to 345 days (PWG, N = 172,131) were analyzed. Four univariate models were used to obtain estimates of (co)variance components using the restricted maximum likelihood method in the BLUPF90 program. Model 1 included Lc and s am . Model 2 included Lc and s am was set to zero. Model 3 did not include Lc. Model 4 did not include Lc and s am was set to zero. These models considered the effects of the Lc as random. Phenotypic variance obtained through cytoplasmic lineage effects was determined for all traits, ranging from 0.07 to 0.15, 0.15 to 0.03, and 0.05 to 0.03% for BW, WW, and PWG, respectively, for models 1 and 2. Correlations between direct and maternal genetic components were positive for WW and negative for BW and PWG. No differences were observed for genetic parameter estimates or animal ranking with the inclusion of s am . For BW, the likelihood ratio suggested that model 1 best fits the data, while model 4 was the most appropriate for WW and PWG. Thus, these models are recommended for genetic evaluations. Despite the low magnitude of cytoplasmic lineages, this effect could predict breeding value and improve the selection of animals for BW in this Nellore population.

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Genetic relationship between growth and reproductive traits in Nellore cattle

Cited by 48 publications

References 28 publications

Genetic relationship among reproductive traits in Nellore cattle

Genetic relationship among reproductive traits in Nellore cattle

Phenotypic plasticity of composite beef cattle performance using reaction norms model with unknown covariate

Inclusion of cytoplasmic lineage effect and direct-maternal genetic covariance for genetic evaluation of growth traits in Nellore cattle

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