Table 1.

Some experiences about supplementations with Co/vitamin B12 in dairy cattle and their most representative effects. BW: body weight, DM: dry matter and CBL: cyanocobalamin.

Action	Levels	Animals	Effect	References
Current cobalt requirements in ruminants	0.1 to 0.2 mg/kg	Dairy cattle	Non-available	[24]
Vitamin B12 supplementation	0.34 and 0.68 µg/kg BW	Dairy cattle	Non-available	[84]
Cobalt supplementation (Co-glucoheptanate)	2.1 mg/kg (dry period) and 1.1 mg/kg (lactation)	Dairy cattle	Increase milk production, weight loss and BCS; no effect on reproductive rates	[85]
Ration supplemented with Co (Co glucoheptonate)	3.6 ppm (mg/kg)	Dairy cattle	Increase hepatic concentrations of B12	[38]
Supplementation with Co	Increased 0 to 1 ppm (mg/kg)	Multiparous vs. primiparous cows	Increase milk production; no benefit for health of cows; no effect in first lactation	[5]
Ration supplemented with Co (Co-sulphate)	Extra supply Co (0.29-mg vs. 0.17-mg/kg DM)	Lactating dairy cows	No influence on ruminal parameters, nor characteristics of milk produced	[20]
Extra supplementation with cobalt	Oral, 0.13-mg vs. 0.27-mg Co/kg DM	Pregnant dairy cows	Slightly higher serum CBL concentrations	[18]
Supplementation dietary with Co	0.15, 0.89 or 1.71 mg/kg of Co, DM	Cows, antepartum period	Increase ruminal synthesis of vitamin B12 in colostrum and milk; no effect on intake of DM, production milk and milk components; no affect on hepatic or serum Co; increase Co in milk	[74]
Supplementation folic acid + vitamin B12	Injections, weekly	Dairy herds, different production levels	Better energy state: increased BCS and decreased fat and protein in early lactation; joint supplementation increases the effects	[30,42]
Supplementation folic acid + vitamin B12	Intramuscularly, weekly, 3 to 16 wk after calving	Multiparous cows in early lactation	Milk production increased 12%	[59]
Supplementation vitamin B12 (even adequate dietary Co-supply)	Intramuscular, weekly, 10 mg vitamin B12	Primiparous cows	Increases blood hemoglobin, B12 in milk and milk yield; decreases MMA serum	[30]
Supplements folic acid and vitamin B12 (combined)	Orally or parenterally	Multiparous cows, early lactation	increases production milk and milk components by improving the energy metabolism	[11,30,59]
Supplementation folic acid and vitamin B12 (alone or joint)	Intramuscular injections, weekly from 3 weeks	until 9 weeks after parturition	Increase folate and vitamin B12 in milk and liver; DM intake not affected; milk and lactose tended lower	[58]
Slow-release boluses (I, Se and Co)	Application intraruminal	Herd with a marginal iodine status	Milk production significantly higher (224 kg more milk)	[86]