SAFE is lifting the lid on one of the dirtiest secrets of the dairy industry… foetal calf blooding. Largely unfamiliar to the public, and done behind closed slaughterhouse doors, serum is produced from the blood of unborn calves. During foetal calf blooding, a pregnant cow is slaughtered, her calf removed, and the blood of her unborn calf is then drained with a needle inserted into the heart without pain relief.