Watch out for copper poisoning in cattle

FifthMainly sheep, and some breeds of sheep in particular, are susceptible to copper poisoning. However, we do occasionally see the problem of copper toxicity appear in cattle, with the Belgian Blue and White breed being the most sensitive to this in Belgium.

Use on the body

Copper is important to the good health of many animal species. Primarily, copper is a cofactor for the absorption of iron from the intestine. In addition, this mineral also has an important effect on the production of blood cells, the nervous system, hair growth, and the growth and maintenance of bones. To maintain all these processes, a minimum amount of copper in the ration is required and both deficiency and excess have negative consequences for the animal.

acute or chronic

Poisoning can be acute or chronic. In acute cases, which rarely occur, a large amount of copper is suddenly absorbed, rapidly producing clinical symptoms. In chronic poisonings, copper absorption is relatively milder, but over a longer period of time. This excess copper is stored in the liver in the case of chronic intoxication, during which time few or no clinical symptoms are observed.

When a toxic amount is present, liver cells are damaged, releasing large amounts of copper into the bloodstream. The damaged liver cells then cause clinical symptoms.

Causes of copper toxicity

There are many reasons why a cow might be poisoned with copper. First of all, copper supplements can go wrong. Adding very large amounts due to a miscalculation can quickly lead to serious consequences.

Another possibility is that there is a very high concentration in the grass feed due to fertilization with, for example, pig manure. Pig food, for example, often contains a lot of copper, as these animals are very tolerant to it. As a result, a lot is also excreted in the manure, which can be absorbed by the plant when fertilizing the fields.

Milk powders and concentrates can also contain high concentrations of copper. A maximum concentration of 40 mg copper/kg is set in European legislation for milk powder, but production errors or highly concentrated milk can cause this limit to be exceeded.

In addition, not only feed, but also water can be the cause of poisoning. Because old copper pipes or kettles have copper in them, drinking water can be contaminated and contain very high concentrations of copper. The last possibility is the low molybdenum content of the serving. Molybdenum is actually a chelate of copper that binds to the metal and prevents its absorption by the animal. When molybdenum concentrations are low, for example in alfalfa, more copper can be absorbed, leading to toxicity.

symptoms

Copper will cause the breakdown of red blood cells in both acute and chronic poisoning. Massive hemolysis causes what is called a hemolytic crisis. Clinical signs that the farmer may notice are drowsiness, weakness with frequent lying down, decreased appetite, dark colored urine, and jaundice. Jaundice, also called jaundice, causes the mucous membranes of the eyes, mouth, vulva, and udder to appear …

On further examination by a veterinarian, liver values ​​will be elevated in most cases and there is frequent formation of methemoglobin in the blood. Methemoglobin arises from deformed hemoglobin in red blood cells. So it is no longer able to transport oxygen throughout the body. This will give the blood a very dark appearance with a brownish serum and the animals will often show pumping breathing. If methemoglobin predominates in the blood, the mucous membrane may also appear light brown.

Diagnosis and differential diagnosis

Based on clinical signs and elevated liver values ​​(AST and GGT), a suspected diagnosis of copper toxicity can be made. For a definitive diagnosis of chronic sepsis, only a liver biopsy can provide a reliable answer as to whether copper is the basis for this specific condition. The determination is not in the blood and can give a normal result, while the animal is still suffering from intoxication. A copper content of more than 150 mg/kg of hydrated matter in the liver is considered toxic and can be used for diagnosis.

In severe poisonings, there is no accumulation of copper in the liver, and thus liver biopsy is not recommended. Normally, it will already be evident in the anamnesis with clinical signs that the animal has had the opportunity to absorb a particular source of copper to a great extent, for example in mineral mixtures, resulting in the onset of acute intoxication. Sometimes clinical signs are noted, such as colic, drowsiness with decreased appetite, yellow-colored mucous membranes or dark-colored urine. However, in severe poisoning, these animals often die suddenly without any clinical signs being observed.

However, some other poisonings can cause similar symptoms. Certain poisonous plants, such as colza, rapeseed, onion and ragwort, as well as various heavy metals are differential diagnoses. With regard to infectious causes, babesiosis, anaplasmosis, leptospirosis, clostridia and bacillus hemoglobinuria should be considered, as they can all also cause hemolysis.

Psychiatric treatment

The first and most sensible step in treatment is immediate reduction of copper uptake and removal of the source, if known. Water and food should be examined to determine the cause of poisoning. In this way, future cases are essentially prevented, but for an animal already affected, this would have little or no benefit. When clinical symptoms are already observed, continuous infusion therapy is strongly recommended to remove existing copper as much as possible. Copper also leads to the formation of methemoglobin. The animal becomes starved of oxygen, so oxygen therapy can be helpful in these cases.

Too high copper concentration in grass feed can also lead to copper toxicity. Photo: LBL

There are copper capture products that bind to the accumulated copper and eliminate it. Ammonium molybdate with sodium sulfate can be used for this purpose. However, these products are prohibited in food-producing animals. Because infected animals are often weakened and the immune system is under stress, secondary infections often occur during treatment, such as pneumonia or inflammation of the vein (vein) in which the catheter is located. Appropriate antibiotic treatment is recommended for these infections. Finally, antioxidants (such as vitamin C) can also be given to limit damage to red blood cells by the oxidizing power of copper. The prognosis is poor in both cattle and other animal species. Treatment is often unsuccessful, especially in advanced or very severe cases.

protection

Excessive intake of copper supplements is the leading cause of toxicity in animals. These are often cases where the farmer did not know he was feeding very high concentrations, because supplementation is done via different methods: via dietary doses, minerals, rations… ideally assessed by liver sampling. Liver concentrations should also be monitored routinely during supplementation. Supplementation can also be prevented by just one route, so that one can keep an eye on the pulse with one finger at all times.

Laurens Chantillon, Ghent University

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