P-64: The Relationship between Polymorphism in Gene of Insulin-Like Growth Factor-I and The Serum Periparturient Concentration in Holstein Dairy Cows

Background: One of the most important metabolic factors affecting the reproductive activity is insulin-like growth factor-I (IGFI) concentration changes after calving. Recently, Maj et al. (2008) discovered a significant association between the IGF-I genotypes based on the 5'-untranslatedregion (5'-UTR) of IGF-I gene and the IGF-I blood level. The objective of this study is to investigate the relationship between polymorphism within the 5'-UTR of IGF-I gene and its periparturient concentration in Iranian Holstein dairy cows. Materials and Methods: In this study, 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 days before calving (prepartum), days 25 and 45 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 CC genotype had significantly higher concentration (Mean ± SD) of IGF-I at 14 dayprepartum (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 that 14 days before calving to day 45 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.