Levels of insulin-like growth factor-1 (IGF-1) are substantially elevated and more bioactive in the milk of cows hyperstimulated with the biosynthetic bovine growth hormones rBGH, and are further increased by pasteurization.
1. Epstein SS. Unlabeled Milk from Cows Treated with Biosynthetic Growth Hormones: A Case of Regulatory Abdication. International Journal of Health Services. 1996;26(1):173-185. doi:10.2190/EDK8-T5RC-LUMR-B2H7
Recombinantly derived bovine growth hormone increases insulin-like growth factor I secretion into milk, leading to a 6-fold increase in milk yield and a 6-fold increase in IGF-I secretion in one udder half.
Prosser, C., Fleet, I., & Corps, A. (1989). Increased secretion of insulin-like growth factor I into milk of cows treated with recombinantly derived bovine growth hormone. Journal of Dairy Research, 56, 17 - 26. https://doi.org/10.1017/S0022029900026170.
Conclusions: Current-use antibiotics and pesticides were undetectable in organic but prevalent in conventionally produced milk samples, with multiple samples exceeding federal limits. Higher bGH and IGF-1 levels in conventional milk suggest the presence of synthetic growth hormone. Further research is needed to understand the impact of these differences, if any, on consumers.
Welsh, J., Braun, H., Brown, N., Um, C., Ehret, K., Figueroa, J., & Barr, D. (2019). Production-related contaminants (pesticides, antibiotics and hormones) in organic and conventionally produced milk samples sold in the USA. Public Health Nutrition, 22, 2972 - 2980. https://doi.org/10.1017/S136898001900106X.
