Sheep have a love/hate relationship with copper. It is a much needed element to help insure health, but too little causes defects, and too much can cause death. Some flock owners might be aware that there is a potential problem with copper intake, but might not be totally informed of what is involved. Therefore, some breeders are almost fanatic about the copper issue without realizing that trying to totally avoid feeds with copper can cause just as severe a problem as feeding too much.
Hair sheep seem to take a back seat in a lot of sheep studies, so the exact data concerning hair sheep and their tolerance/intolerance to copper is not really known at this time. Some of the breeds (mostly European) that are prone to copper toxicity are Suffolks, Oxfords, Shropshires, and Texels. Merino sheep are lesser prone, and even more so with Finnsheep. Mature ewes of the down or medium wool breeds are more susceptible.
Copper is needed for the production of melanin, iron metabolism, elastin and collagen synthesis, as well as the health of the nervous system and immune system. Ewes that are deficient in copper give birth to lambs that have partial paralysis of the limbs, and may be sway-back and unable to stand and nurse. Adult sheep may have poor, brittle wool as well as fertility and lactation problems due to copper deficiency.
Copper is found in grains, plants, hay (coastal, alfalfa, etc), mineral blocks, vitamins, feed-through wormers, and soil. A lot of people tend to concentrate only on grains and mineral blocks but overlook the fact that sheep get copper from other sources as well. Most sheep can easily tolerate 8-10 parts per million of copper. Please make note of this though: Most feed manufacturers do not include copper on the ingredient tag if it is a “trace” mineral - that is, “traces” of copper found normally in an ingredient. They usually only include the amount of ADDED copper. You can look at an ingredient tag and tell if the manufacturer is aware of the copper problem in sheep, because not only will they list the ppm of copper, but also the ppm of molybdenum, zinc, sulfur, all of which bond with copper and form insoluble complexes, limiting copper absorption. The molybdenum and zinc are especially important as copper antagonists. A sheep should not have a diet (everything it consumes) of more than 15-20 ppm of copper unless they are also getting molybdenum, but again, it depends on the breeds of sheep as mentioned above. Most sheep feeds have 25-35 ppm of copper but also add molybdenum. The ratio of copper to molybdenum should be 10:1. High rates of molybdenum binds up too much copper and then you are dealing with a copper deficiency. Molybdenum should be shown on the tag at a rate of 3 ppm.
Copper deficient soils produce poor crops. In some areas, copper is routinely applied to soil where alfalfa is grown.
Some of the higher protein horse feeds have too much copper for sheep - 35 ppm. A lower protein horse feed may have the desired amount - 8-10 ppm. Poultry, cattle, and especially swine feeds have copper levels too high to feed to sheep. Some swine feeds have 300 ppm of copper, or better. An entire flock of sheep was lost due to chronic copper poisoning (CCP). When the flock owner fertilized his sheep fields with a pig manure slurry, he didn’t realize that the manure had copper at dangerously high levels, and when the soil and forage were tested where the manure had been added, it had copper levels at 85 ppm!!
Copper toxicity has two forms: acute and chronic. The acute form takes place after a sheep ingests an extremely high amount of copper at one time. The chronic form (CCP) results after a steady ingestion of a marginally high level of copper after several weeks or months. Even a level of 25-28 ppm of copper (found in feeds for sheep) after a length of time with no copper antagonists may cause CCF.
Copper is stored in the liver and is released through the kidneys at a slower rate than it is stored. A sheep’s liver will not store only the needed amounts, but ALL the copper it ingests, so herein lies the problem. Copper in the liver builds up over a long period of time, and then when the animal is stressed due to handling, lambing, weather changes, illness, hauling, etc., the liver cells rupture, releasing the copper into the bloodstream. Copper stores in the liver may be 1000-3000 ppm before reaching a threshold and is released. This results in a hemolytic state that is massive. Hemolysis is a normal function where old red blood cells deteriorate but are replaced by healthy red blood cells. In the hemolysis that takes place after the rapid release of copper in the bloodstream, the red blood cells breakdown at such a rate that up to 60% of the red blood cells circulating in the bloodstream may be damaged and cannot be replaced quickly enough. This is how sheep are lost to copper toxicosis.
Most often, the first sign of a problem with copper toxicity is finding a dead sheep. There are many other things that can cause a sudden death with no symptoms, such as enterotoxemia (pulpy kidney). If you are lucky, you might detect some early warning symptoms. The sheep may look anemic with pale membranes and be very depressed. The membranes then turn yellow as jaundice takes effect. Seventy-five percent of sheep with CCF will die. If CCF is suspected, a long term treatment of daily ammonium molybdate and sodium sulfate drenches is required. Sometimes a solution can be prepared to spray on the feed for sheep that are still eating. Remember though that sheep with a severe reaction may die before showing any symptoms.
Beware of feeds claiming to be for goats and sheep. Read the label and look for copper content. Goats can tolerate higher levels of copper, and it is surprising how many of the sheep and goat feeds are detrimental to your sheep due to high amounts of copper. Do not feed calf creep feeds or milk replacers that are offered for multiple species. The copper content will be too high. Only feed lamb milk replacer. Those manufacturers include copper because it is an essential mineral, but they also include copper antagonists, usually molybdenum.
Question your feed dealer as well as the manufacturer. Bringing awareness to this issue is badly needed. I personally questioned one manufacturer several times before they finally added the amounts of copper to their tags, and it was a minimum of 22 ppm and a maximum of 38 ppm !! When your dealer takes the hint that you are a concerned owner, then they are more conscientious about the products they offer.
I cannot stress enough the importance of having a necropsy performed on your animals. Many diseases share symptoms. For instance, an unthrifty, weak lamb that appears to have deformities could be copper deficient, or have White Muscle Disease (a result of a deficiency in selenium). Unthrifty, anemic-looking sheep could have enterotoxemia, CCF, liver flukes, or any number of ailments. Upon necropsy, a sheep with CCF is obvious. The membranes are yellowish, the kidneys are extremely dark, and the urine is bloody. Also take into consideration how you manage your flock and the copper level of everything ingested. If you are unsure, you can have your grains and hays tested for the amount of copper they contain.
As an interesting side note, there are many breeds of dogs that are prone to copper toxicosis. Bedlington terriers have the worst problem with it, but Dobermans are prone to it as well. As a breeder of Dobermans, this is of great concern to me. Testing has proved that copper toxicosis in dogs is due to a malfunctioning gene that impairs the biliary excretion of copper. The gene has been located in the Bedlington terrier, and now DNA testing of potential breeding stock will show whether a dog is affected, clear or carrier. Breeding only clear x clear or clear x carrier will avoid producing affected dogs (ie, avoid breeding carrier x carrier or affected x carrier or affected x affected). Hopefully, genetic markers will be found in the future for other dog breeds with this problem. It is equally surprising to see some of the copper contents on various dog foods - some are 75 ppm or higher.
Unfortunately, searching for a genetic marker or undergoing related testing to look for a remedy, and then expecting flock owners to test each sheep, would be cost prohibitive. The best we can do as flock managers is to take into consideration all sources of copper, and manage accordingly.
Anita Garza, Founder/Registrar
