18 January 2002

Sudden change may reveal a lack of cobalt

HOUSING lambs and feeding on concentrates could trigger signs of previously undetected cobalt deficiency.

That is the view of Neil Sargison, published in Vet Record. "A sudden change in diet, such as when hill lambs are housed for fattening, sometimes results in animals displaying neurological signs such as head pressing. The underlying cause of this can be cobalt deficiency."

A sudden rise in diet carbohydrate can overload the liver in cobalt-deficient lambs leading to toxic chemicals entering blood, which damages brain tissue, says Mr Sargison. "Where head pressing, blindness and wandering behaviour are seen in recently housed lambs, investigate the possibility of cobalt deficiency."

But by the time such symptoms appear, it can be too late to treat successfully, he says. So he suggests checking for symptoms of deficiency in the grazing season. "These can include ill thrift, open fleece, pot belly and a watery discharge."

Blood testing can be used to confirm the condition as other diseases can lead to similar symptoms, he adds.

There are several methods of treating cobalt deficiency. "When dosing every four weeks, wormers fortified with cobalt can be used as a short term boost. But cobalt does not mix with ivermectin, so when this wormer is used, cobalt must be given as a separate drench."

Alternative treatments are injecting vitamin B12 monthly, or for animals such as ewe lambs, which will be kept for longer than slaughter lambs, cobalt boluses, he advises. &#42