Genetic evaluation reveals high heritability for growth and low heritability for reproduction in Nelore cattle, suggesting environmental management must accompany genetic selection.
Key Points
To estimate genetic parameters and evaluate genetic and phenotypic trends for growth and reproductive traits in Nelore cattle raised under humid tropical conditions.
Analyzed records collected between 2016 and 2022 for growth traits (weaning weight n=1266, yearling weight n=832, post-yearling weight n=733) and reproductive traits (age at first calving n=639, calving interval n=1772, stayability n=1122).
Estimated variance components using Bayesian inference and evaluated phenotypic and genetic temporal trends using linear regression on birth year.
Growth traits exhibited moderate to high heritability (0.43 to 0.58), whereas reproductive traits showed low heritability (0.04 to 0.13).
Favorable phenotypic trends occurred across all traits, including weaning weight (+3.09 kg/year), yearling weight (+2.72 kg/year), post-yearling weight (+3.91 kg/year), age at first calving (−0.68 months/year), and calving interval (−11.90 days/year).
Significant genetic progress was limited to age at first calving (−0.03 months/year) and calving interval (−3.35 days/year), while remaining traits showed no significant genetic changes.