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

GH gene is one of the important genes that affect the productive and physiological traits in livestock. This study aimed to use a meta-analysis to determine the association of the GH gene with growth traits in cattle. Four different genetic models were used: dominant LL + LV versus VV, recessive LL versus LV + VV, complete 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 an effect of GH genotypes on the birth weight (BW) under the recessive (p<0.05) and complete over dominant (p<0.01) models. However, no association (p>0.05) was found under the dominant model. In terms of co-dominant model, the GH polymorphism showed a significant association with BW (SMD = 0.359, 95% CI = 0.119 to 0.599, p = 0.003) under LL vs. LV genotype combination patterns. No association was found between GH polymorphism and BW under LL vs. VV genotype combination. The results showed that the LL genotype had a significant effect on BW traits from LV and VV genotypes when comparing the models. The results showed an effect of the GH on ADG under four genetic models (p<0.05).