rBGH and rBST
Recombinant Bovine Growth Hormone and Recombinant Bovine Somatotropin are synthetic hormones given to cows in order to increase milk production. Farmers often inject their animals with these two genetically engineered hormones for profit.
So what happens when we drink the milk from injected cows? Studies suggest that rBGH and rBST could increase the risk of developing certain types of cancers, including prostate, breast, and colon cancer. As a result, Canada, most European countries, and others have banned these synthetic hormones because they considered them dangerous to both humans and animals.
Unlike these countries, the US currently allows farmers to inject cows with these genetically engineered hormones.