The effect of polymorphism in gene of insulin-like growth factor-I on the serum periparturient concentration in Holstein dairy cows.

Abstract: Objective: To investigate the relationship between polymorphism within the 5′-untranslated region (5′-UTR) of IGF-I gene and its periparturient concentration in Iranian Holstein dairy cows. Methods: Blood samples (5 mL, n = 37) were collected by caudal venipuncture from each animal into sample tubes containing the EDTA and DNA was extracted from blood. In order to measure IGF-I concentration the collection of blood samples (n = 111) was also done at 14 d before calving (prepartum), 25 and 45 d postpartum. Results: We found evidence for a significant effect of C to T mutation in position 512 of IGF-I gene on its serum concentration in dairy cows in Iran. Cows with CC genotype had significantly higher concentration (Mean±SD) of IGF-I at 14 d prepartum (91.8±18.1) μg/L compared to those with TT genotype (73.3±14.4) μg/L (P=0.04). A significant trend (quadratic) was found for IGF-I concentration, as higher in CC cows compared to ones with TT genotype, during the 14 d before calving to 45 d postpartum (P=0.01). Conclusion: We concluded that C/T transition in the promoter region of IGF-I gene can influence the serum concentration of IGF-I in periparturient dairy cows. [Copyright &y& Elsevier]