A meta-analysis of the association between Growth Hormone (GH) gene polymorphism (AluI) and growth traits in cattle breeds

The growth hormone (GH) is an important gene that affects the productive and physiological traits in livestock. This study aimed to use a meta-analysis to determine the association of the GH-AluI gene polymorphism with growth traits in cattle. Four different genetic models were used: dominant LL + LV versus VV, recessive LL versus LV + VV, over dominant LL+VV vs. LV and co-dominant LL vs. LV, LL vs. VV and LV vs. VV. The random-effect model was used in data analysis based on I2. Meta-analysis showed a significant effect of GH-AluI genotypes on the BW (p<0.05; p<0.01) under the recessive and over dominant models. However, no significant associations were found with the dominant model (p>0.05). In terms of the co-dominant model, the GH polymorphism showed a significant association with birth weight (BW) (SMD = 0.359, 95% CI = 0.119 to 0.599, p = 0.003) with the LL vs. LV genotype combination patterns. There was no association between the GH polymorphism and BW under the LL vs. VV genotype combination. When comparing the models, the results showed that the LL genotype significantly affected BW traits. Moreover, the findings showed the effect of the GH on average daily gain (ADG) under the four genetic models (p<0.05). The current study confirmed the association between the GH gene and growth traits in cattle