Resumen
- The objectives of this research were to estimate genomic-polygenic and polygenic parameters and to evaluate prediction trends as Brahman fraction increased from 0% to 100% in a subtropical multibreed Angus-Brahman (MAB) population for four growth and reproduction traits using single-step genomic-polygenic (GPM) and polygenic models (PM). Traits were 365-d yearling weight (YW), yearling reproductive tract score (RTS), age at first calving (AFC), and first calving interval (FCI). Numbers of phenotypic records were 1758 for YW, 381 for RTS, 1385 for AFC, and 985 for FCI. The pedigree file had 6869 calves, sires, and dams, and genotype file contained 115,711 actual and imputed GGPHD150k SNP markers from 1547 animals. The 4-trait GPM and PM included contemporary group, age of dam (YW only), sex of calf (YW only), direct heterosis, maternal heterosis (YW only) as fixed effects, and animal and residual as random effects. Genetic parameters were estimated using REML procedures and computed using AIREMLF90. Heritabilities were slightly higher for GPM than PM (0.47 vs. 0.45 for YW, 0.31 vs. 0.30 for RTS, 0.14 vs. 0.12 for AFC, and 0.31 vs. 0.29 for FCI).