It's the clear yellowish fluid that remains from whole blood after clotting - fibrinogen turned into fibrin, enhancing the release of a cocktail of valuable cell growth stimulating components - centrifugation and separation from the blood cloth.
Bovine serum comes from blood taken from domestic cattle.
While the procedure of making serum may seem to be straightforward, the processing of serum takes place under very tightly controlled conditions.
Bovine serum is a by-product of the meat industry.
Bovine blood may be taken at the time of slaughter, from adult cattle, calves, very young calves or from bovine fetuses (when cows that are slaughtered are found to be pregnant). It is also obtained from "donor" animals which give blood regularly.
Blood is available from bovine fetuses only because a proportion of female animals that are slaughtered for meat for human consumption, are found unexpectedly to be pregnant.
Bovine serum is categorized according to the age of the animal from which the blood was collected as follows:
- "Fetal bovine serum" comes from fetuses
- "Newborn calf serum" comes from calves less than three weeks old
- "Calf serum" comes from calves aged between three weeks and 12 months
"Adult bovine serum" comes from cattle older than 12 months