Copper Deficiency in Pygmy Goats
Reviewed by Dr. William Holleman
An article on Copper Toxicity appeared in the December 1994 issue of The Pygmy Goat WORLD. Copper deficiency lies at the other end of the spectrum. Some of the medical terminology and reasoning is similar in both extremems, but the symptoms and treatment vary greatly.
Many factors contribute to both copper toxicity and deficiency. Management, breed, age, size, concurrent disease problems, environment (e.g. weather, stress), mineral components in nutrition (e.g. molybdenum, sulfur, selenium, and iron), individual metabolism, vaccinations, and general health may all play a role in copper imbalances. Most important is the intake of copper and molybdenum, another mineral metal which binds copper. Copper and molybdenum affect the absorption and excretion of each other. Dr. Patricia Talcott, a Veterinary Toxicologist with the University of Idaho, states that the normal ratio in the total diet of copper to molydbenum is 4:1 to 6:1. If more than 3 ppm of molybdenum is present in the diet, copper deficiency may be a very real threat. Excessive calcium, sulfur and iron may also interfere with copper absorption.
Copper deficiency can be referred to as neonatal ataxia, enzootic ataxia, swayback or spectacle disease. These names refer to symptoms that are common in copper deficiency. The symptoms are directly related to the essential role that copper plays in a number of metabolic and developmental functions. Specifically, copper is involved in myelination (protective covering for nerves), osteogenesis (bone production), hematopoiesis (production of red blood cells), hair pigmentation (copper-containing enzyme is necessary for melanin 'dark pigment' production) and normal growth. It stands to reason that without a sufficient amount of copper, these normal functions are hampered. Resulting symptoms include: ataxia (swaying, staggering) weakness, loss of pigmentation and decoloration of the hair, anemia, ill thrift, abortion, decreased milk production, diarrhea, infertility, paralysis with extension of the hind limbs, muscle wasting, spasticity of hind limbs, bone fractures, poor growth and muscle weakness. Copper deficiency can also cause stillborn kids, kids that are weak or birth, kids that die after birth due to starvation (failure to nurse) or die after weaning. Coccidiosis and round worm infections seem to predispose goats to copper deficiency, and pneumonia may become a secondary problem.
Initial diagnosis can be made based on symptoms but should be confirmed with diagnostic testing. Low blood (serum) copper levels are not useful in diagnosis. Concentration of copper in the liver is the best indicator of copper status, and biopsy of the the liver is the gold standard test. Lesions may be found postmortem in the brain and spinal cord. Although definitive copper requirements have not been established for goats, we can extrapolate from other species. Dr. Patricia Talcott says that a good rule of thumb is that copper/molybdenum levels should be no higher than 6:1. At higher than 10:1, the animal is very susciptible to copper toxicity. If the ratio is less than 2:1, the animal is predisposed to copper deficiency. Ratios are only important in the total diet, not in tissue samples.
In one recent case, a pygmy goat herd in Western Washington was copper deficient. The first sign was weight loss in one doe who soon began to sway and became recumbent. The owners took her to their veterinarian where she died. Test results showed no mineral toxicity but the doe had coccidiosis, which seems to go hand-in-hand with copper deficiency. The family was told to treat the herd with CoRid®, but a short time later they began experiencing severe losses. Their goats became weak and swayedon their back feet to the point where they couldn't stand. They were being fed alfalfa, bluegrass hay and a corn/oat/barley mix, and they had access to a salt lick and sheep minerals. The goats were eating but still losing weight even with deworming and coccidia treatment. Other symptoms that the family noticed were a sweet sick smell before the animals died, crying due to pain and later, after the correct diagnosis, they clearly noticed white-colored rings around the eye (pigment loss). [Editorial note: hair discoloration around the eyes was different than the normal frosted markings found in Pygmy goats.] Diarrhea was also a factor with the constant wobbling. After many autopsies and talking with specialists, the goats were diagnosed with copper deficiency and treated accordingly. The cause of the copper deficiency in this case was an abundance of lime in the bluegrass hay and excess sulfur in the water that depleted the animals' copper. Now, when the family sees a goat with white rings around the eyes (copper deficiency can be called spectacle disease due to this hallmark symptom), they know to treat that animal with copper supplements. The white circles, however, usually do not appear until the animal has been deficient for some time. This herd has had no deaths since the diagnosis and treatment for copper deficiency.
As mentioned in the Copper Toxicity article, copper requirements vary with breed and environment and depend on dietary molybdenum levels. Recommendations for specific levels of dietary copper require consideration of environmental factors such as soil molybdenum concentrations, pasture plant species being grazed, and fertilization practices. Molybdenum and sulfur reduce available copper. Calcium, cadmium, iron, and zinc inhibit absorption of copper. Lime, used as fertilizer, also reduces copper and increases molybdenum uptake by pasture plants. This was part of the problem in Western Washington. Liming has also caused copper deficiency in dairy cows on New Zealand pastures. If copper deficiency is suspected, you may want to get mineral tests on your feed, water and other supplements.
Treatment for copper deficiency depends on the cause. Testing feeds, water and soils may be necessary to discover if the problem is primary or secondary. Primary copper deficiency is caused by low copper levels in soil and forages grown on the soil. Secondary is when normal amounts of copper are present in soils and feeds but uptake and absorption are impeded by the presence of copper antagonists such as molybdenum, iron, manganese, cadmium, lead and sulfates. Treatment is determined by the cause. For example, if copper deficiency is caused by an abundance of molydbeum, treatment may include supplementation of copper in the diet. If the goat has been diagnosed with copper deficiency, supplementing orally may not save its life. Just as with selenium, in order to raise the level, injections are necessary. Pregnant does can be given copper glycinate subcutaneously at a does of 150 mg at mid-gestation to prevent subsequent copper deficiency in kids. Kids can be given 60 mg of copper glycinate subcutaneously at birth if pregnant does were not treated. Oral copper sulfate in the drinking water has also been used at a dose of around 1.5 g per head, per week. The point is to supplement with appropriate amounts of copper. This always seems a bit scary since copper toxicity is also a problem but as stated earlier, the symptoms for copper toxicity are totally different than deficiency. Be aware of these symptoms and look at each goat every day. Noticing any pigment changes, weight loss, or weakness just may save your herd.
Goats usually get sufficient copper from their daily diet. The problem arises when something takes place to upset this balance, i.e., high levels of sulfur or molybdenum in water or feed. It's a good idea to check with the person you purchase your feed from to check their fertilizing and growing practices. Do they lime the soil or use any topical soil treatment that could harmful to your animals?
Deficiency and toxicity are both deadly copper problems that bring with them the need to know the make-up of your goats' diet. Toxicology and mineral tests are available through many independent laboratories. A very well-known and helpful authority in the field is:
Dr. Patricia Talcott, Veterinary Toxicologist
Analytical Sciences Laboratory
The Holm Research Center
University of Idaho
Moscow, ID 83844-2203
Phone: (208) 885-6109
Dr. Talcott works closely with the people at Washington State University.
Watch for symptoms in your herd. Copper deficiency is a slowly progressing, chronic problem. By the time you notice symptoms, the animal has been deficient for some time. Don't become frustrated with treatment. One shot will not cure the problem. Just as it took a while for the deficiency to develop, it will take time to cure it. Being alert for the symptoms could save time and lives.
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Dairy Goats - Best info, many links
Importance of Copper for Fertility and Health, by Jackie Nix
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Copyright February 1995