Genome Wide Association Study Reveals New Chromosome Regions Affecting Age at First Calving in Nellore Cattle

: In the genomic-wide selection (GWS) era, the identification and use of molecular markers such as SNP allows the prediction and accuracy gain of genomic estimated breeding values (GEBV) for economically important traits. The objectives of this study were to estimate genetic parameters for age at first calving (AFC), to perform genome-enabled predictions in Nellore and well as to identify QTLs associated to the most relevant SNPs. acquired on 529 of these animals (24,572 SNPs). A multi-trait model was fitted under a MCMC Bayesian approach using a single step BLUP methodology. We identified 0.05% of the most relevant SNP for AFC as well as reported QTLs related with AFC. Heritability estimates were 0.18 and 0.41 for AFC and WW, respectively. The genetic correlation between AFC and WW was 0.06. The top 0.05% most relevant SNPs were detected on chromosomes 7, 9 14, 16, 18, 21, 24, 26 and 29. The most relevant SNP marker was detected on BTA14, when we so observed a peak which could reveal the importance of this chromosome for AFC. Moreover, we identified new regions that might be related with AFC.