The objective of this study was to estimate the genetic and phenotypic correlation between age at first calving and early growth traits for Holstein Frisian x Ethiopian Boran crossbred cattle in central highland of Ethiopia. The data used for this study was sourced from records of Holetta Agricultural Research Center (HARC) dairy cattle herds’ farm collected from 2000 to 2019. The genetic and phenotypic correlation values for age at first calving (AFC) and early growth traits were estimated using WOMBAT software through multivariate analysis of animal model. The estimated direct genetic correlation between age at first calving and early growth traits ranging from weak positive (0.11±0.33) for yearling weight (YW) to strong positive of 0.77±0.36 for weaning weight (WW). The phenotypic correlation ranged from moderate negative of -0.44±0.03 for AFC and YW to weak positive correlation of 0.12±0.04 for AFC and YW. Both environmental and genetic effects could influence phenotypic correlations of the age at first calving and early growth traits. The results of genetic correlation between early growth traits and AFC indicate that early growth traits should be given some consideration in selection criteria of heifers. Due to the genetic antagonism between those traits, a cow with high growth performance has poor reproductive performance. Selection could be done with caution.
Keywords: Age at first calving, crossbred, correlation, Ethiopia, genetics, growth