Vitamin B-12 responses to cobalt pellets art beef cows

Objective To assess the effectiveness of cobalt pellets in maintaining adequate Vitamin B-12 in beef cows an pasture of low cobalt content. Design A field experiment in a herd grazing cobalt deficient pasture. Animals Mature Murray Grey cows. Procedure Cows were given a single oral dose of 0, 1, 2 or 4 cobalt pellets (30 g pellets containing 30% by weight cobaltic oxide) with a selenium pellet and a grub screw, Samples of blood, liver, faeces and milk for chemical analyses were collected at intervals over a period of 2 years after treatment. Results A single cobalt pellet raised liver vitamin B-12 con centration of cows above that of untreated cows for at least 28 weeks? and 2 or 4 pellets for 57 weeks. Plasma vitamin B-12 concentration was an unreliable indicator of the effectiveness of cobalt pellet therapy. Milk vitamin B-12 and faecal cobalt concentrations increased in response to cobalt pellet therapy, Conclusion These studies show that one cobalt pellet will prevent vitamin B-12 inadequacy in beef cows far between 28 and 57 weeks; two or four pellets will prevent inadequacy for 57 to 75 weeks. Milk vitamin B-12 concentration may be a useful indicator of the effectiveness of cobalt pellets in increasing the vitamin B-12 supply in lactating cows.