When dealing with herd health and imbalances in mineral nutrition, the answers are generally not black and white. One such instance is copper deficiency.
Copper deficiency in cattle can result in a wide range of problems -- from poor hair coat to reduced weight gains and impaired immune systems.
One of the most visible signs of copper deficiency is change in hair color. Black animals develop a reddish or gray tint to the hair (grayness is noted especially around the eyes), and red animals become more bleached. The coat becomes dull instead of shiny.
Copper deficiency generally has the most detrimental effect on young, growing animals, and can result in unthriftiness and lower weight gains, diarrhea, poor response to vaccinations, lameness, brittle bones, etc.
Sometimes it's hard to tell (without tests) the difference between signs of copper deficiency and parasitism (worms), since both produce general signs of diarrhea, anemia and emaciation. While a positive response to adding copper to the ration can be an adequate field test, fecal examination for worm eggs should also be done.
One of the first signs of copper deficiency in some calves may be stiffness in gait. The ends of the cannon bones become enlarged and painful (sore fetlock joints). Pasterns may be upright and the calf may seem to have contracted flexor tendons, walking on its toes. Some calves become severely lame.
Bruce Anderson, DVM., Ph.D., and professor at University of Idaho's Caine Veterinary Teaching Center, says a number of factors can come together to produce a variety of problems. Copper deficiency can be primary (when intake of copper is inadequate) or secondary (when dietary intake is sufficient but other factors prevent utilization of copper in the body).
Primary deficiency occurs when feed is grown on copper deficient soils. Secondary deficiency often occurs when dietary excess of other elements (molybdenum, iron, zinc, lead or calcium carbonate) tie up copper so it can't be utilized.
Clive C. Gay, D.V.M., and director of the field disease investigation unit at Washington State University, says many regions have a copper deficiency. "In the West we have problems due to the presence of molybdenum. This is most common with alkaline soils, since molybdenum uptake by plants is influenced by pH of the soil. In the East, soils are more acid and producers run into more problems with primary copper deficiency. Other soils that present a risk are peat, organic soils, or soils with high water tables, depending on the pH of the soil."
"Sulfur tends to combine with molybdenum to cause problems, but can be a problem in itself, especially in acid soils, or in conjunction with lime fertilizer. Molybdenum is often a problem in valley bottoms or swales; there is more molybdenum in these soils than on the uplands. It is also taken up in higher concentrations in legumes than in grass," says Gay.
In the South and Southeast, many soils (especially in Florida) are low in copper, he says. The problem is often accentuated by use of fast growing species of grasses that don't have time to pick up as much copper from the soil as slower growing grasses. Tropical grasses might grow 8 to 10 feet, while a western bunchgrass might grow 10 to 12 inches during the growing season.
Anderson referenced the Cow Calf Health and Productivity Audit of 1996 which focused on forage analysis from 18 states and 352 samples. About two thirds of 30 native grass samples were marginal to deficient in copper.
"Add that to the fact these grasses tended to be high in iron, and you get the kind of interference that gives you a serious copper deficiency in the animal. Among the 109 grass hay samples, copper was marginal or deficient in a number of samples. About 14 percent of samples were copper deficient and 50 percent were marginal."
"Another factor that can push a marginal copper supply into the deficient category is interference by iron and/or molybdenum. About 10 percent of the samples had enough molybdenum to do that," he says.
Gay said producers should look at the copper to molybdenum ratio. When forage samples contain less than 8 10 parts per million of copper, they are borderline deficient. The problem is compounded when molybdenum levels are in excess of 1 3 parts per million, or when the copper to molybdenum ratio falls below 3:1 or 4:1, he explained.
Molybdenum induced copper deficiency can create weak and brittle bones in calves, says Anderson. "We've seen that happen here in Idaho. High molybdenum hay gave us a copper deficiency that resulted in calves with broken legs. Bones become weak and brittle in a fast growing copper deficient calf. In one instance a rancher was jumping calves out of a truck and several snapped their legs. Their liver tests for copper showed almost none," he says.
"We also get a lot of wrecks in weaned calves in the fall, and when I've check them, we find them rock bottom for copper, and often low in selenium as well. A lot of calves that come off ranges in the Northwest are short on copper. Some of them get by, but others are practically void of copper. Pneumonia problems can be due to copper deficiency and an unhealthy immune system," says Anderson.
"Feedlot pneumonia outbreaks are legendary, but more avoidable today than in the past. Calves come in off the range in the fall, get weaned and trucked, and vaccinated as they enter the feedlot, and the trouble begins. The copper deficient calves have a crippled immune system and may not respond well to the vaccines we hit them with right off the truck; they also are unable to resist diseases."
"Copper deficiency can also hurt a cow herd, causing reduced reproductive efficiency," he says.
Heifers may be later reaching puberty and cows may be slower to cycle after calving. Fertility in heifers can be impaired, especially when copper is tied up by molybdenum.
A 1987 study showed that the increased levels of molybdenum in diet delayed puberty in yearling beef heifers by 8 12 weeks, and greatly reduced conception rate in cows. There can be reduction in first service conception rates, lower embryonic survival (this was evident in situations where producers were using embryo transfer) and reduction in overall pregnancy rates.
In situations where cows develop severe copper deficiency due to interference by excesses of other trace elements such as molybdenum or sulfur, they may show normal estrus behavior (but ovulation does not occur) and then cease cycling. Semen quality in bulls can also be affected.
Dr. Patricia Talcott, a professor at Idaho State University in Moscow and Washington State University in Pullman, works in the diagnostic laboratory and sees a lot of copper deficiency in cattle from the Pacific Northwest.
"One of the biggest tips to producers trying to identify a copper problem is recognizing whether this has ever been a problem in their area. If it has, and if you raise cattle long enough, eventually you will experience the problem. Many people feel that if they have good management strategies, they will be immune to the problem. But this may not be true every year, since copper levels in soil and forages will vary from year to year, depending upon environmental factors, weather conditions, soil factors, fertilization, etc.," she says.
"Another thing that makes it difficult to figure out a copper problem is that often you just see the subclinical problems," she says.
You don't have obvious things like discoloration of the hair coat. The cattle may just have lowered immunity (more incidence of disease).
"You may have an increased number of animals succumbing to respiratory diseases, or an increased number dying from diarrhea or intestinal problems, or calves not putting on as much weight as you would expect. You might not even think of copper deficiency. The latter is not the only problem, but might be a risk factor for creating other problems," says Talcott.
"Molybdenum in plants (picked up from the soil) will tie up copper in a complex in the gastrointestinal tract, and this does not allow the copper to be absorbed by the body. The cattle might be getting a lot of copper in their diet, but they can't utilize it, since it is bound to molybdenum," she says.
"If you suspect a copper deficiency, run some tests. You can collect forage samples, and submit them to a laboratory," Talcott says.
Tests can determine the copper content and molybdenum content of feeds. Blood tests or liver tests can determine the copper status of an individual animal.
Blood tests work well (and are less invasive than liver biopsies) but you must keep in mind that when an animal is under stress (as from disease), the bloodstream pulls trace minerals from the liver. This could give you a false reading for copper. It's best to test calves during the grazing season, rather than when they have just been weaned and stressed.
Another way to monitor the copper levels in your herd is to take a liver sample whenever an animal dies, or from an aborted third trimester fetus. The liver can be put in the freezer until you can send it in for testing. Keep in mind, if the animal died from severe infection, the liver may show low copper levels even if copper levels were normal when the animal was healthy. However, in most cases an occasional liver sample from animals that are butchered or die can give you good clues about your herd's copper status.
Talcott says, "Depending on whether you have a primary or secondary copper deficiency and depending upon the management of that particular herd, there are several strategies to enhance copper levels."
These can range from supplementing with mineral blocks, to injections of various copper products, oral drenching or copper boluses that provide delayed release.
There are many ways to supplement. What is used depends on what the producer feels is most cost effective for the situation.
Producers should work with a veterinarian and/or nutritionist to help them figure out the best way to address a problem and to determine the proper dosage or level of supplementation to much copper can be toxic.
"Cattle are not as susceptible to copper poisoning as sheep, but you still want to be careful that you don't overdo it during long term treatment. Copper poisoning generally won't occur quickly, but a long term copper supplementation program with excessive copper intake can lead to a chronic problem with toxicity," says Talcott.
"Poisoning only rarely occurs with an injection; it's more likely to happen with long term over supplementation. If there is too much copper going into the animal (if you over estimated the amount the animals need), and you are not doing repeated blood or liver sampling to assess the treatment, you could potentially get into a problem."
Most people who start a supplementation program keep monitoring the situation; it's wise to work with a nutritionist and/or veterinarian to set up the long term goals of the program.
Gay says the most common way to deal with copper deficiency is to put copper into the salt /mineral mix, but it's not 100 percent effective because cattle have such variable salt intakes; some will consume enough and others won't. And it's hard to get cattle to eat salt when grazing forages are grown on alkaline soils.
"The solution is not always easy. Getting copper into calves on the range by using a mineral supplement, for instance, is nearly impossible," says Anderson. "Some of them eat it, and some don't. It's a hit and miss kind of thing. When you get them in and vaccinate them, their immune systems aren't able to respond well to the vaccinations.
Producers who get calves in and immediately put them on a ration highly supplemented with copper may have better results, but there's a little bit of lag time. If you vaccinate them at the same time, you may have problems anyway," he says.
"Even if calves have adequate levels of selenium and copper, the stresses we often put on them can cause problems. But if they are short of copper and selenium, it can be 'Katie, bar the door!"'
Gay says the best method he's found for accurate supplementing is to use copper oxide boluses. The boluses contain tiny copper oxide needles in a gelatin capsule which is placed into the rumen.
"The gelatin dissolves and the needles are released, lodging in the papillae of the rumen. They sit there a while, then gradually pass into the abomasum, where they dissolve and make the copper available for absorption," says Gay.
"You must have the correct dose, however. These were first put on the market 15 years ago with a dose of four grams, which was far too low. You need 20 to 25 grams. One bolus, given to an animal at the beginning of the grazing season, will prevent copper deficiency for six months. In our experience, this has proven to be 100 percent effective," says Gay.
"Problems tracing back to copper deficiency can be costly and exhausting. In addition, among the calves we don't pull for clinical disease, many don't gain as well as they should; we find out later that they took a production limiting hit from 'silent' pneumonia," Anderson says.
It pays to know the copper status of your cattle. Copper deficiency can be an obvious villain, but more often it can be a sneaky, unseen profit robber.
(Reprinted with permission from the May 2003 Limousin World.)