Copper Oxide
This is probably the most economically important of the ruminant trace deficiencies, particularly in cattle.
Effects
Effects of deficiency can be subclinical, possibly confined to depression of growth, immune response and phagocytic activity. The most specific clinical effect is white muscle disease - sudden and severe myonecrosis, usually bilaterally symmetrical, affecting the muscles of the limbs, diaphragm and often the heart, causing sudden death. These effects, which are direct effects of oxidative tissue damage, can be precipitated by exercise.
Selenium deficiency is also associated with a wide range of conditions where the biochemical mechanisms are not understood. These are abortion, weak or stillborn calves, retained placenta and infertility. In sheep, early embryonic death and resorption is a common feature.
Occurrence
As well as having serious effects, selenium inadequacy is widespread in the US. Low pasture levels are found at about the same order of frequency as for copper.
There are also known areas where selenium toxicity can occur, usually where there is a basin or other geological feature causing a local concentration of leached salts. These areas are generally circumscribed and well recognised.
As for copper, selenium intake in grazing animals varies with pasture composition, species dominance, stage and rate of growth. Young, rapidly growing pasture is most often associated with problems. This makes it hard to predict selenium intake on a geological basis, since pasture factors, including soil ingestion (a source of selenium) are often more important, and vary within the same property and from month to month. Knowledge of the history of a particular property is valuable, but problems can be precipitated by for example land improvement, with fertiliser application and re-seeding.
Maternal transfer
There is good placental transfer, and the cow will deplete her own liver copper reserves while foetal levels increase. The ability of milk-fed calves to absorb copper is much greater than in ruminating calves.
Functions
There are several enzyme roles for example
- Cytochrome oxidase: energy utilisation
- Superoxide dismutase: protecting against oxidative tissue damage by dismutation of superoxides,
- Lysyl oxidase: collagen and elastin metabolism affects connective tissue and bone
- Tyrosinase: melanin synthesis
- Dopamine hydroxylase: cardiac and central nervous function
Effects of Deficiency
- Growth depression
- Feed/gain increased
- Delayed conception
- Reduced fertility
- Depressed immune response (phagocytic and immune globulin)
- Spontaneous fractures
- Altered coat colour
- Anaemia (microcytic, hypochromic)
- Diarrhoea
- Death
The principle economic effects of copper deficiency are on growth, fertility and resistance to disease.
Growth
The focus on growth is, of course, in the feedlot. However, effects of copper deficiency on growth of calves and growing cattle can be substantial. Dr. Clive Gay of Washington State University has shown benefits of up to 32% in weight gain of growing cattle, through use of copper oxide needles, in low copper/high molybdenum situations.
Cattle in feedlots normally have full levels of all the micronutrients included in their rations. However, cattle entering the feedlot with low copper status are known to be particularly slow to pick up. In fact, one feedlot consultant. Dr. Dave Bechtol, has named low copper status as the most important single cause of poor initial growth in cattle entering feed yards.
Fertility
Delayed first oestrus, delayed conception and poor fertility have been associated with copper deficiency for many years. However, there is now evidence that at least some of this problem may be a direct effect of molybdenosis. Work in Scotland by Phillippo and others (1) showed effects of molybdenum in delaying puberty, reducing ovulation, suppressed oestrus and reducing conception. The prime effect appears to be reduced output of leutenising hormone. Because of the strong interaction between molybdenum and copper, this specific molybdenum effect is something which has so far been investigated in cattle on experimental rations and with small numbers. However, the evidence is quite strong.
In practice this would point against using copper injections to control a copper/molybdenum infertility problem, since Cu-Mo binding is primarily a gut phenomenon and injections will not reduce molybdenum absorption. Similarly, copper chelates are claimed to escape molybdenum tie-up in the gut. If so, this would reduce or eliminate their effectiveness in controlling molybdenum-related infertility.
Immunity
Copper deficiency is known to reduce the immune response, with increased susceptibility to bacterial infections. There is also evidence that phagocytic killing is reduced and antibody-antigen inter-reactions impaired.
Occurrence of Copper Deficiency
Opinions differ on the value of considering the geological background to trace element deficiencies, including copper. Whilst the copper content of soil is certainly related to the parent rock, the picture is confused by:
- Pasture species composition
- Trace element uptake by the plant, reduced by heavy liming.
- Rate and stage of pasture growth. Rapidly growing pastures are the most problematic.
- Soil ingestion during grazing causing increased iron intake.
In 1966, Corah and Dargatz (2) gave results of a survey of a number of elements in herbage throughout the US. This showed only 35% of pasture samples to have adequate copper. In addition, they found excessive molybdenum in 57.8% of samples, and excessive iron in 28.7%, without taking account of iron from ingested soil. Sulfur was not included in this survey.
A Canadian survey (3) of slaughtered cattle found only 36% to have adequate liver copper levels. Whilst a similar abattoir survey has not been done in the US, available data indicate that low animal levels can be found in most states, including Montana.
Diagnosis
The available tools are
- a) Clinical examination
- b) Pasture analysis
- c) Blood analysis
- d) Liver analysis
Copper deficiency should be considered when any of the signs listed earlier are encountered. None are specifically diagnostic, and there is enough genetic variation in coat colour to cloud even that simple issue. However, it can serve as a useful starting point. There is nothing strictly quantifiable about rough-coated gingery Herefords, or Angus with a grey halo. However, it can give a quite characteristic picture, which includes a lot of individual variation within a group. You may even see the classic "spectacles" of hair loss round the eyes.
2. Pasture analysis
Veterinarians sometimes neglect this aspect but it is easy, relatively cheap and should tell you if the status of the animals is on the way up or down, and should point to the underlying cause of the problem. Molybdenum, iron and sulfur should be included and it is best that the samples should not be washed, so that ingested soil is included in the analysis.
Pasture analysis would, of course, fail to reveal a problem of, say, high sulfur in the drinking water. Given a known copper problem, it would be reasonable to check the water if the pasture is not at fault.
Critical pasture values are as follows:
| Copper/Molybdenumn: | Minimum 4-10 ppm copper (NRC) although 10 ppm copper, with a Cu/Mo ratio Molybdenum of at least 5, is desirable. At levels of copper above 10 ppm, the critical Cu/Mo ratio reduces to 2. |
| Iron: | As little as 250 ppm will deplete copper reserves. 350 ppm and over presents a problem, and this amount can be obtained from ingested soil alone. |
3. Blood and liver analyses
Both are useful, and both give an index of the animal's current status, without revealing whether the status is improving or declining. Plasma and serum values are very similar. Plasma and liver values have been correlated by Claypool and others (4) in Orgeon. They considered 540 pairs of samples.
This revealed, firstly, a high variation of individual values. It was also evident that mean plasma values remained relatively constant over a very wide range of liver values, between 40 and 500 ppm of liver DM. Below liver values of 40 ppm, plasma levels dropped sharply. Claypool concluded that plasma levels of 0.6?g/ml or below indicated deficiency. However, higher levels did not prove sufficiency. Liver storage of copper results in high values, up to about 400 ppm (dry weight) but seldom higher in cattle.
Published critical copper values (5) for wet liver samples are
- Normal: 30-120 ppm (approx 100 - 400 dry)
- Marginal: 10-30 ppm
- Deficient: below 10 ppm (approx 35 ppm dry)
Liver biopsies are clearly very useful in determining current herd status, provided sufficient samples (say 10) are taken. In New Zealand, where trace element control is almost a religion, some farmers like to regularly (eg annually) have their herd's copper status monitored by biopsies or abattoir samples.
Short of biopsies, bloods will reveal a serious problem, and pasture results can be very useful in identifying the underlying nutritional problem.
Control
- In feed - where animals are fed, copper can be included in the feed. NRC recommendation is 4 - 10 ppm. Copper sulphate works and is cost effective compared to chelates, even allowing for any differences in availability.
- Free access supplements - in grazing/foraging animals, free access supplementation of important nutrients is unreliable. Variation in intake is huge, and for some individuals will be zero.
- Injections - Duration of effect is up to about 6 weeks, and injection site abscesses are always a problem.
- Copper oxide needles - Copasure and Copinox, manufactured by Animax. Unlike copper oxide powder, which passes swiftly through the gut with very little absorption, copper oxide rods lodge for several months in the rumen, reticulum and omasum. Gradually carried to the abomasum and exposed to HCl, partial solution and absorption takes place over a period of about 3 months. This raises liver levels to somewhere approaching the maximum, and trials show levels remaining above controls for 8 to 12 months. One annual dose is generally sufficient.
Dosage recommendations are:-
- Young cattle, 100 - 300 kg bodyweight: 1 x Copasure/Copinox 24g/27g capsules
- Adult cattle, over 300 kg bodyweight: 1 or 2 x Copasure/Copinox/Coprac SC 24g/27G capsules depending on the severity of deficiency.
- Ruminating calves, 75 to 100 kg: 2 x Copasure / Copinox 4g Ewe/Calf capsules
- Ewes: 1 x Copasure / Copinox Ewe/Calf 4g capsule (or 2 x Copasure / Copinox Lamb 2g capsules) for the prevention of congenital swayback the dose should be given at tupping or during the first half of pregnancy. It may be advisable to administer the dose during the second or third month of pregnancy rather than at tupping on farms where copper deficiency is particularly severe.
- Lambs: Over 5 weeks of age, 1 x Copasure / Copinox Lamb 2g capsule
Products
The following products feature this element:
