Maternal phenotypic records shape the genetic parameter estimates in Nelore beef cattle

The number of dams with their own phenotypic records is crucial for estimating the genetic correlation between direct and maternal effects in beef cattle. In this study, using multi-trait analyzes, we assessed the impact of varying the percentage of dams with own records (0, 20, 35, 50, and 70 %) on genetic parameter estimates in Nelore beef cattle. The analyzes focused on key traits in the selection index: weaning weight (WW), post-weaning weight gain (PWG), scrotal circumference, and muscling score. Direct heritability estimates remained relatively stable across data structures, while maternal heritability and the covariance between direct and maternal effects showed important variations. The genetic correlation between direct and maternal effects of WW linearly shifted from negative in D0 (−0.20) to positive in D70 (0.31), emphasizing the impact of increasing the number of dams with own records. Maternal phenotypic records influenced genetic associations between traits, notably WW and PWG (0.13 in D0 and 0.36 in D70). These findings highlight that changes in data structure can impact the estimation of genetic parameters for multiple traits. The study underscores the importance of robust data structures, maternal phenotypic records (>35 %), and complete pedigree information to obtain reliable estimates of genetic parameters in beef cattle.