Use of weaning management group as a random effect for a more robust estimation of genetic parameters for post-weaning traits in Nellore cattle

V.B. Pedrosa, J.P. Eler, J.B.S. Ferraz, E. Groeneveld
2014 Genetics and Molecular Research  
Data from 69,525 animals were used to compare two types of analyses, one of them having the weaning management group (WEMANG) included as an effect in the contemporary group (F_ WEMANG) and the other considering the weaning management group as a random effect, not related to the mathematical model (R_WEMANG) for post-weaning traits. The components of (co)variance were estimated for pre-weaning traits (birth weight and weaning weight) and for postweaning traits [scrotal circumference (SC),
more » ... gain from weaning to 18 months of age (WG) and muscle score (MUSC)] in Nellore cattle, based on a complete animal model. Heritability of SC, WG and MUSC for the F_WEMANG model was equal to 0.46 ± 0.02, 0.38 ± 0.03 and 7014 V.B. Pedrosa et al. ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (3): 7013-7021 (2014) 0.26 ± 0.01, and for the R_WEMANG model it was 0.45 ± 0.02, 0.31 ± 0.03 and 0.25 ± 0.01, respectively. Genetic correlations between all the studied traits varied between 0.07 ± 0.01 and 0.77 ± 0.03 in F_WEMANG and between 0.02 ± 0.01 and 0.76 ± 0.04 in R_WEMANG. The R_ WEMANG model allowed a decrease in the number of contemporary groups as well as an increase in the number of observations per group without significant alterations in heritability coefficients, for the postweaning traits. Consequently, the analysis became more robust and avoided having contemporary groups with low variability.
doi:10.4238/2014.february.21.7 pmid:24634293 fatcat:v6mcpan6lrfrnb6tci5zwqgq7e