ASK THE VET (Zinc Toxicity)

In my last column, I wrote about lead poisoning. In this column I would like to talk about a second type of heavy metal toxicity -- zinc. Birds can be exposed to zinc if they are housed in flights or cages made of galvanized wire, since zinc, and sometimes lead, is often a component of this wire and the clips used to construct these flights. Zinc is also a component of galvanized food dishes, certain game pieces, and pennies minted after 1982. In addition, the white rust that can form over zinc is also toxic to birds.

The signs of zinc toxicity may be variable. Birds exposed to a large amount of zinc may display ataxia (loss of balance), green diarrhea, and may die suddenly. Chronic exposure may be expressed as depression, intermittent lethargy, neurologic signs such as seizures and ataxia, and increased thirst and urination. Death may occur as a result of anemia and damage to internal organs.

Just like the diagnosis of lead toxicity, diagnosis of zinc toxicity can be very difficult. Radiographs may demonstrate metallic densities in the gastrointestinal tract. Blood levels for zinc may be run in a laboratory.

Radiographic and clinical signs are the same for zinc and lead toxicities; thus one can't be differentiated from the other. Fortunately, treatment is the same for both.

1. Cathartics may aid in the passage of small particles.
2. A magnetized instrument may be employed to remove galvanized wire pieces from the digestive tract.
3. Chelating agents may also be used, either given orally or by injection.
4. Surgery or endoscopic removal may be necessary to remove zinc particles that are visible radiographically.

As with lead, the best way to avoid zinc toxicity is by preventing your bird's exposure to it.