Animals most affected
ingestion of fodder contaminated with
copper sulphate when it has been used as a fungicide in large quantities (Bordeaux
mixture comprises 1-3% copper sulphate), or of hay contaminated by industrial
pollution (farmland cultivated close to mines, smelting works or foundries);
ingestion of feeds supplemented with
copper (e.g. salt licks,
dietary mineral additives) given to sheep in regions with a marked copper deficiency
in the soil.
In some countries (Australia, New Zealand) there are particular plants (e.g. Heliotropum
europaeum) which contain very specific alkaloids which, when ingested, are capable
of altering the metabolism of the animal's liver cells, increasing their uptake of
copper from the diet.
The compound is hepatotoxic. Toxic doses
consist of repeated or prolonged ingestion of fodder containing 15-20 ppm copper,
expressed as dry weight of the feedstuff.
Important note: in the
body there is an antagonistic relationship between molybdenum and copper. A lack
of molybdenum in the diet (levels at less than 1-2 ppm/dry weight) can cause copper
poisoning despite normal copper levels in the diet (8-12 ppm/ dry weight).
Presentation of fulminating, severe jaundice
bright yellow mucous membranes, yellow-coloured
haematuria, bloody nasal discharge;
oedema of the head and neck (presenting
several hours before the onset of jaundice).
In general, death occurs within a few
hours of presentation of these symptoms.
Note: the development of the above syndrome in a herd of animals follows
a characteristic pattern. As individual sensitivity to copper varies between
animals, jaundice develops in some of the animals - at varying intervals and
over a relatively long period of time (several weeks).
yellow carcase with muscles dark brown
oedema and haemorrhages of the gastric
acute degeneration of the liver and kidneys;
petechiae in the subepicardium, haemopericardium;
occasional serohaemorrhagic effusions
(in the thorax, mediastinum, pencardium, abdominal wall).
Once jaundice is evident, treatment is unlikely
to be effective. Before jaundice presents (or where there have already been several
cases of jaundice in a herd), the following regimens may be instituted.
Antidotes: chelation therapy
dimercaprol (BAL), 24 mg/kg, im, twice
in the first 24 hours, then two to four times in the next 48 hours;
EDTA (sodium calcium edetate 25% w/ v),
4050 mg/kg, iv, one to two doses to be given daily for 2-3 days;
ammonium molybdenate (50500 mg/ day per
animal) and sodium thiosulphate (0.3-1 g/day per animal) administered orally
in the diet for 10 to 15 days.
sample of feedstuff, hay.
Note: whether the level of copper is normal or abnormal, measure the levels of
molybdenum to check if there is a deficiency of this element.