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Definition: cobalt from Collins English Dictionary

n

1 a brittle hard silvery-white element that is a ferromagnetic metal: occurs principally in cobaltite and smaltite and is widely used in alloys. The radioisotope cobalt-60, with a half-life of 5.3 years, is used in radiotherapy and as a tracer. Symbol: Co; atomic no: 27; atomic wt: 58.93320; valency: 2 or 3; relative density: 8.9; melting pt: 1495°C; boiling pt: 2928°C

[C17: German Kobalt, from Middle High German kobolt goblin; from the miners' belief that malicious goblins placed it in the silver ore]


Summary Article: Cobalt from Black's Veterinary Dictionary

Cobalt is one of the mineral elements known to be essential for health, but only required in minute amounts — a trace element. Its function is to act as a catalyst in the assimilation of iron into haemoglobin in the red blood corpuscles. Cobalt is essential to the synthesis of cyanocobalamin (vitamin B12) and a lack of it leads to a deficiency of this vitamin. (See BUSH SICKNESS; ‘PINING’; ANAEMIA; TRACE ELEMENTS; MOLYBDENUM.)

Cobalt deficiency

occurs most frequently in parts of Scotland, Northumbria, Devon, and North Wales. Affected sheep may show signs such as progressive debility, anaemia, emaciation, stunted growth, a lustreless fleece, and sunken eyes from which there is often a discharge, with a mortality of up to 20 per cent.

However, signs are seldom as definite and clear-cut as the above description might suggest, and in many flocks a ‘failure to thrive’ is all that is observed or suspected. Sometimes poor performance comes to be accepted as normal, and yet could be remedied by preventive measures after soil analyses had indicated a cobalt deficiency.

Nowadays, 0.25 parts per million of cobalt in the soil is regarded as an acceptable level; and 0.17 ppm as constituting a deficiency.

In a comparison of two methods of treatment — the administration of a single cobalt ‘bullet’, and two doses of cobalt chloride — both appeared to have been equally effective in alleviating the deficiency as judged from the liveweight response of the lambs. Treatment by cobalt bullet was, however, more effective in increasing and, more importantly, in maintaining serum vitamin B12 (closely related to cobalt) than was the cobalt-dosing regime.

Poisoning

Overdosage must be avoided. Twelve beef stores on cobalt-deficient land died when they were not only offered a cobalt supplement in boxes, but drenched as well with cobalt sulphate ‘measured’ by the handful. (See also under TRACE ELEMENTS.)

© Edward Boden and Anthon Andrews, 2015

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