Copper Deficiency

Pure deficiency is very rare, as a ewe’s requirement is only 1mgCu/kg DM. However, there are several elements that can antagonise copper and these change the picture significantly.  Iron and sulphur will bind with copper in the rumen, this copper can’t be absorbed and passes out in dung, it is rare to get clinical signs of copper deficiency due to high iron levels but it can worsen the effect of molybdenum.

Molybdenum Toxicity

Molybdenum combines with sulphur to form thiomolybdate, this will bind copper present in the rumen. The complexed thiomolydate and copper is then passed out in the dung.  Any left over thiomolybdate is absorbed into the body where it binds the copper dependent enzymes, preventing them from working.  Although, this produces the signs commonly associated with copper deficiency (poor growth, diarrhoea, steely wool, poor fertility, swayback) it is caused by the high levels of molybdenum and is therefore better described as molybdenum toxicity.  Supplementing copper to prevent this only works if the copper is available in the rumen, to bind molybdenum, before it enters the body, this is the case for Cosecure boluses but not for many others.

If you are concerned for your flock, please call and speak to one of our vets.  In the meantime, take a look at our next news piece on Copper Toxicity.