Vitamin B12, also called cobalamin, is a red crystalline powder and is the only vitamin containing metal elements. Vitamin B12 is the only vitamin that needs the help of intestinal secretions to be absorbed. It participates in the production of bone marrow red blood cells, prevents pernicious anemia, and prevents brain nerves from being damaged.

Vitamin B12 is required for the development, myelination, and function of the central nervous system; healthy red blood cell formation; and DNA synthesis. Vitamin B12 functions as a cofactor for two enzymes, methionine synthase and L-methylmalonyl-CoA mutase.
Deficiency of Vitamin B12 will reduce the hatchability of chickens and the reproductive rate of pigs. The clinical symptoms of vitamin B12 deficiency include loss of appetite, growth arrest, simple anemia, and severe neurological symptoms.