tremors or seizures<\/a>.<\/p>\nThen remove heavy metal from bodily tissues with a binding or chelating agent<\/strong>:<\/p>\n\n- Calcium EDTA (Calcium disodium versenate, 3M Pharmaceuticals):\u00a0 35-50 mg\/kg every 8-12 hours by intramuscular or subcutaneous route for 5 days (Elliott 2025, Wismer 2016)<\/li>\n
- Dimercaptosuccinic acid (Succimer, Chemet): \u00a025 mg\/kg every 24 hours by mouth for 10 days. In a study evaluating cockatiels (Nymphicus hollandicus<\/em>), both DMSA and Ca EDTA were effective chelating agents in. Because DMSA is administered orally, it may be easier than other chelating agents for bird owners to administer at home. However, the narrow margin of safety of DMSA indicates that this agent should be used with caution (Denver 2000).<\/li>\n
- D-Penicillamine (Cuprimine, Merck): \u00a030 mg\/kg by mouth every 12 hours for 7 days minimum<\/li>\n<\/ul>\n
Chelation therapy may be unnecessary if the lead source is promptly removed. If initiated, renal function should be monitored throughout treatment (Richardson 2006). Lead stored in bone and soft tissues can complicate therapy, causing fluctuating blood lead levels. Redistribution of tissue-stored lead has been observed with both CaEDTA and DMSA.”<\/p>\n
If a source of heavy metal is seen on radiographs, removal of lead<\/strong> from the gastrointestinal tract via endoscopy, surgery, or gastric lavage may also be indicated. Lubricants such as mineral oil or corn oil, cathartics (i.e. magnesium sulfate), or bulk agents such as peanut butter, psyllium or oral cellulose products may also be used to remove heavy metal from the digestive tract.<\/p>\nRemoval of particles with an iron base using a feeding catheter loaded with neodymium-ferro-borium alloy magnets has also been described.<\/p>\n
Prevention of lead toxiciosis<\/h3>\n
Since companion parrots are curious by nature, it can be challenging to prevent chewing and ingestion of undesirable objects. Pet birds should always be supervised during their time outside of the cage, and owners should also remove all known sources of heavy metal or limit exposure to areas with heavy metals (Box 1).<\/p>\n
Control of problem areas for wildlife consists of plowing to lessen the availability of spent shot to birds. The use of non-toxic steel or bismuth shot for waterfowl hunting is also now required in the United States. This switch from lead to non-toxic shot has reduced the number of birds dying from lead poisoning in America. The United States and Canada are also considering a ban on lead fishing sinkers.<\/p>\n
<\/p>\n
Zinc<\/h2>\n
Zinc is a trace metal or mineral essential for health. Zinc is involved in cell replication and in development of cartilage and bone (McDonald 2006). The primary target organs in zinc toxicity are the kidneys and pancreas.<\/p>\n
Sources of zinc<\/h3>\n
Zinc toxicity usually arises from the ingestion of zinc-coated wire or metallic foreign bodies such as pennies minted after 1983. One penny contains approximately 2440 mg of elemental zinc (Richardson 2006).<\/p>\n
\nBox 4. Sources of zinc<\/strong><\/caption>\n\n\n\n\n- Galvanized clips and wires<\/li>\n
- Some powder coated cages<\/li>\n
- Washers, nuts and bolts<\/li>\n<\/ul>\n<\/td>\n
\n\n- Snap fasteners, padlocks, some toy hangers<\/li>\n
- Pennies made in 1983 or later<\/li>\n
- Zinc oxide cream or ointment<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Galvanized wire is another common source of zinc intoxication in parrots, especially cheap, imported wire. Aviary birds are often housed in galvanized steel wire cages. Galvanized coatings can contain up to 99.9% zinc, however galvanized wire can also contain lead (Platt 2006). Galvanized dishes should never be used since zinc can leach into the water.<\/p>\n Powder coating is a protective coating for the cage. While formulas differ by manufacturers, most contain no zinc, however some imported powder-coated cages use zinc to expedite setting of powder coating (Richardson 2006).<\/p>\n Zinc can also leach out of zinc-coated iron shot into the environment. Waterfowl can then ingest vegetation and sediments contaminated by zinc (Platt 2006).<\/p>\n A number of websites report that the adhesive in paper towel and toilet paper rolls contains significant amounts of zinc, however this appears to be more urban legend than fact.<\/p>\n Once, when we had a look at the actual zinc content in the glue in those paper rolls, and then “borrowed” the nutritional requirements for zinc in chickens; presuming that the requirements in a parrot would be similar, we were able to show that if a parrot ate toilet paper exclusively with that zinc containing glue, there would still be a need for zinc supplementation to meet the nutritional requirements for the bird. (Speer 2010, Veterinary Information Network)<\/em><\/p><\/blockquote>\nClinical signs of zinc toxicosis<\/h3>\nAs with lead toxicity, signs of zinc toxicity can be vague and non-specific, but clinical signs are often related to disease of the gastrointestinal tract, pancreas, kidneys and\/or central nervous system. Although this is a bit controversial and reports are anecdotal, zinc toxicity has also been associated with an \u201cextreme\u201d loss of plumage and feather damaging behavior (Box 5).<\/p>\n \n\n\n| Box 5. Clinical signs of zinc toxicity<\/th>\n<\/tr>\n | \n\n\n- Lethargy<\/li>\n
- Crop stasis, regurgitation<\/li>\n
- Green or yellow diarrhea<\/li>\n
- Weight loss<\/li>\n<\/ul>\n<\/td>\n
\n\n- Seizure activity<\/li>\n
- Paresis<\/li>\n
- Polyuria\/polydipsia<\/li>\n
- Feather loss? Feather damaging behavior?<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Diagnosis of zinc toxicosis<\/h3>\nThe minimum database in zinc toxicosis may be relatively unremarkable. Mild to moderate regenerative anemia due to erythrocyte loss has been described with zinc toxicity (Box 6). Since zinc toxicosis typically results from chronic exposure to fine metal powder, a metallic density is rarely observed on survey radiographs.<\/p>\n \n\n\n| Box 6. Diagnostic testing for zinc toxicity<\/th>\n<\/tr>\n | \n| Hematology<\/td>\n | Mild to moderate anemia<\/td>\n<\/tr>\n | \n| Whole blood levels<\/td>\n | Zinc > 2 ppm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n The normal blood zinc ranges are only weakly understood for a variety of species. Additionally, in a trial following induced zinc toxicity in cockatiels, blood zinc levels were extremely inconsistent as a diagnostic predictor (Howard 1992). Part of the confusion stems from the fact that zinc is an essential nutrient. Normal homeostasis regulates zinc levels based on variations in gastrointestinal content, bioavailability and individual nutritional needs. Significant diurnal variations in zinc values have also been documented in 15 adult psittacine birds (Rosenthal 2005).<\/p>\n Nevertheless in the presence of clinical signs, blood zinc levels exceeding 200 \u03bcg\/dl (or 2 ppm) are suggestive of toxicity. Collect heparinized whole blood to measure zinc levels. Take care in how the blood sample is drawn and stored to avoid contamination.<\/p>\n | | |
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