Relationship between Vitamin B12 and Cobalt Metabolism in Domestic Ruminant: An Update

SIMPLE SUMMARY: We review the role of cobalt and vitamin B12 in animals, especially in ruminants. Vitamin B12 is an essential part of the enzyme systems involved in multiple metabolic reactions and mainly in the formation of energy from ruminal fermentation. Signs of deficiency, as well as cobalt toxicity, in animals are described. The level of cobalt in ruminants can be assessed by measuring the blood or tissue concentrations of cobalt or vitamin B12, as well as the level of some metabolites such as malonate, homocysteine or transobolamine in blood or methylmalonic acid in urine. The requirement for cobalt (Co) is around 0.11 ppm (mg/kg) dry matter (DM) in the diet, although current recommendations advise supplementing the diet up to 0.20 mg Co/kg DM, which seems to increase animal production, especially in dairy cattle. ABSTRACT: Cobalt, as a trace element, is essential for rumen microorganisms for the formation of vitamin B12. In the metabolism of mammals, vitamin B12 is an essential part of two enzymatic systems involved in multiple metabolic reactions, such as in the metabolism of carbohydrates, lipids, some amino acids and DNA. Adenosylcobalamin and methylcobalamin are coenzymes of methylmalonyl coenzyme A (CoA) mutase and methionine synthetase and are essential for obtaining energy through ruminal metabolism. Signs of cobalt deficiency range from hyporexia, reduced growth and weight loss to liver steatosis, anemia, impaired immune function, impaired reproductive function and even death. Cobalt status in ruminant animals can be assessed by direct measurement of blood or tissue concentrations of cobalt or vitamin B12, as well as the level of methylmalonic acid, homocysteine or transcobalamin in blood; methylmalonic acid in urine; some variables hematological; food consumption or growth of animals. In general, it is assumed that the requirement for cobalt (Co) is expressed around 0.11 ppm (mg/kg) in the dry matter (DM) diet; current recommendations seem to advise increasing Co supplementation and placing it around 0.20 mg Co/kg DM. Although there is no unanimous criterion about milk production, fattening or reproductive rates in response to increased supplementation with Co, in some investigations, when the total Co of the diet was approximately 1 to 1.3 ppm (mg/kg), maximum responses were observed in the milk production.