Copper exists in many different forms that may be added to feed: The most common forms are listed below. A summary of relative availability of the different copper sources was published by No Dakota State Univ in 2006. Copper sulfate was assigned 100%, and other sources of copper were compared to it.

Copper lysine is a form of chelated copper. This means that the copper sulfate is bound to an organic compound such as the amino acid lysine as shown above. Other chelating agents are proteins, a group of amino acids, or a complex carbohydrate. Some studies have shown that chelated copper was 30% more available than copper sulfate alone. The reason for feeding or injecting a chelate is because it is believed to be more bioavailable than the mineral alone. Part of the reason for this difference is presence of antagonists (compounds that interfere with the absorption of copper) and the other part is the function of copper measured in that particular study. The term bioavailability is defined as the portion of the mineral eaten that is absorbed from the digestive tract and is available to the animal to perform its function. Trace minerals have many different functions which make availability difficult to measure. Growth and performance of the animal are measures of bioavailability as is presence in enzymes, presence or absence of antagonists, chemical balance in the body, and toxicity. Growing plants are more liable to cause copper problems than hay from that particular meadow or pasture. Too often we tend to overlook mineral problems during the grazing season and concentrate on minerals during the time we are feeding hay and other roughages. If this is done, we may lose performance and fertility that could be achieved if copper had been supplied. Chelated sources of copper are used when a high level of performance is desired or stress is present. I use chelated copper in receiving or weaning rations, embryo transplant projects, and artificial insemination programs. I also use it when a high level of an antagonist is present. Antagonists that are common in the Northwest are high levels of iron (over 500 ppm), high levels of sulfur (found often when feeding corn distillers grain with solubles—above 0.30% sulfur), and when molybdenum is found to be greater than 1.0 ppm. Molydenum may be found in sub-irrigated meadows, swampy areas, and in alfalfa hay from certain areas. When molybdenum is present in high levels we most commonly add enough extra copper to create a ratio of 5 ppm to 10 ppm copper for each 1 part per million molybdenum. The ratio of copper and zinc is also important for optimum performance. A ratio of 3-4 to1 is fine. Uh Oh...time for my feed testing ad. The only way you can know whether your forage has high levels of the antagonists mentioned is to have your feed tested at a lab than runs the trace minerals tests on a regular basis.

Another means of giving copper is by injection. In years past, copper glycinate was on the market. It has been removed from the market, but is available through your veterinarian. He can make up the suspension or have it made by a licensed drug compounding lab. If you choose to use this method of providing copper, be sure to shake the bottle routinely so that the copper and glycinate don’t separate. It is believed that this injection lasts for 6 months. Evidence from Utah indicates that the injectable form was less successful in maintaining blood copper than was the bolus.

Copper it also part of an injectable trace mineral that includes selenium, manganese, and zinc. This product is available through your veterinarian. This injection enters the blood stream very rapidly and also dissipates rapidly. Blood values rise rapidly after the injection, but fall back to pre-treatment levels within 30 to 45 days. The manufacturer does not represent this product as a solution to year round trace mineral nutrition, but rather as a compliment to a sound program. If used, it should be given before an expected stressful event. In my mind there has not been enough research to show that the injection of copper is necessary when cattle are maintained on a supplement with sufficient copper year round.

A copper bolus is also available. It is given to cattle with a balling gun. It lies on the floor of the paunch and slowly releases copper oxide needles. It seems to function best when given twice yearly when copper deficiency is severe.

It’s important to recognize that copper is TOXIC! It is sometimes called bluestone and is added to the water in a stock pond to kill algae. It can also kill good bugs in the paunch, so don’t just give copper in any form without justification. Sheep are especially sensitive to copper toxicity; a mineral that is safe and beneficial to cattle may kill sheep. This doesn’t mean that sheep don’t need copper, they do, but they can’t handle an overage.

As a side note, I work with a client in Missouri. His forage has so much copper, that we actually feed sodium molybdate to overcome copper toxicity. In Canada cattle were grazed on the site of a molybdenum mine. The forage was very high in molybdenum however the cattle showed no signs of copper deficiency. Supplementing with copper got no response.

Several different studies have shown that Simmental and Charolais cattle have a higher requirement for copper than Angus. There doesn’t appear to be any difference between
Angus and Herefords for copper requirements. No data were found for other breeds.

Years ago I attended a symposium on copper. We were fortunate enough to have Dr. Neville Suttle from the University of Edinburgh as our key-note speaker. He has studied copper for his entire professional career. He noted that the animal should be your guide for copper issues no matter what theory was or what forage samples or blood values showed. If the animal responded to copper, then extra copper was needed. If reducing or removing copper from the diet brought a favorable response, that is your answer.