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 or al 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, Sampl es of blood, liver, faeces and milk for chemical analyses were collect ed at intervals over a period of 2 years after treatment. Results A si ngle cobalt pellet raised liver vitamin B-12 con centration of cows ab ove that of untreated cows for at least 28 weeks? and 2 or 4 pellets f or 57 weeks. Plasma vitamin B-12 concentration was an unreliable indic ator of the effectiveness of cobalt pellet therapy. Milk vitamin B-12 and faecal cobalt concentrations increased in response to cobalt pelle t therapy, Conclusion These studies show that one cobalt pellet will p revent vitamin B-12 inadequacy in beef cows far between 28 and 57 week s; two or four pellets will prevent inadequacy for 57 to 75 weeks. Mil k vitamin B-12 concentration may be a useful indicator of the effectiv eness of cobalt pellets in increasing the vitamin B-12 supply in lacta ting cows.