Overdose of copper can prove deadly and costly.
Byline: VET'S VIEW IAIN CARRINGTON
COPPER is an essential trace element, but it can be toxic if either a large amount is taken suddenly, or an excess is ingested over a period of time.
Acute copper poisoning is relatively uncommon, but has been noted in sheep after over-dosage with injectable copper preparations, often leading to death in less than 24 hours. This highlights the need to always read the administration instructions before the use of any drug or vaccine.
Symptoms are non-specific and sudden in onset, including severe gastroenteritis with blue/green diarrhoea, abdominal pain, anorexia and shock; severe disturbances of the blood occur if the animal survives for longer than three days; mortality is high overall.
Chronic copper poisoning is much more common and mostly seen in sheep, but recently has been observed in dairy cattle due to over enthusiastic supplementation in the thought this would improve fertility.
If levels of copper are too high in the diet, it builds up in the liver until there is no more storage capacity, causing a release of copper into the bloodstream; this then displays as an acute event due to the damage caused to the liver and red blood cells, which leads to their disruption affecting the ability to transport oxygen.
Stress can also play a major part in precipitating the condition.
In sheep, breed can also play a role as North Ronaldsay, Texel, Suffolk and a number of short-wool breeds are more susceptible to the effects of copper toxicity.
Symptoms commonly observed are depression, weakness, anorexia, thirst, anaemia and jaundice.
A severe liver damage accounts for the early deaths, later on animals may succumb to kidney failure.
Treatment is problematic and the outlook is often poor with more than 75% of those affected dying.
Even those not showing symptoms are not free from risk, as losses within a group may continue for some time, despite the diet being corrected.
When a diagnosis is made, you should discuss your options with your own veterinary surgeon.
As chronic poisoning generally results from a dietary load and/or efficient absorption of copper, prevention rests on reducing exposure. Elements such as iron, sulphur and molybdenum block the uptake, which can then make diets that have a high copper level much less toxic.
When formulating a diet for livestock, it is important to consider that high copper concentrations can be found in pasture silage and crops grown on ground fertilized with pig or poultry manure, distillery byproducts containing pot ale syrup, palm oil and also molassed sugar beet.
Chelates should be used with care, as they can increase copper availability. Supplementation of copper should only occur when there is proven deficiency or reduced availability in the diet giving evidence of a shortage.
Short-wool breeds, such as Texel, <Bare more susceptible to the effects of copper toxicity
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|Publication:||The Journal (Newcastle, England)|
|Date:||Nov 3, 2014|
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