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Copper deficiency can
result in a wide range of problems in cattle--everything from poor
hair coat to impaired immune system and reduced weight gains.
Clive C. Gay, DVM, Professor and Director of the Field Disease
Investigation Unit (Department of Veterinary Clinical Sciences) at
Washington State University, says that a survey was done in
Washington state after people recognized that a certain area had a
copper problem. “We found that a large part of the state is at
risk for deficiency; producers may have this deficiency in their
herds and not know it,” he says. One of the problems is that the
signs may not be recognized. EFFECTS OF DEFICIENCY - Coat color
changes are a good indicator, if you see them. Black cattle tend
to turn more brown, or reddish, or even gray, on the face or body.
Red cattle may look bleached. Hair loses its luster and becomes
dull and coarse. But in many cases you won’t find these signs, he
says.
“Probably the most
common indication is a decrease in weaning weights. A rancher may
look at his cattle and is not very happy with the weights, and
looks at his neighbor’s cattle and they are about the same,
because they are on the same soil type.” So the rancher chalks it
up to the grass not being very good that year, or something like
that, unaware of the underlying problem, says Gay.
Another sign of copper
deficiency is a less healthy immune system. “There is more
susceptibility to disease. This may be seen on the farm, but more
commonly is a risk factor for when the calves enter the feedlot.
Another manifestation we’ve seen, though not too commonly, is
where the presenting sign is fractures of major bones. The cattle
have a high fracture rate when being run through chutes and things
like that--procedures where you would not normally expect to see
fractures. The bones are more fragile.” It’s usually the big bones
of the legs, or even the shoulder blade.
“The depressed weaning
weights and the hair color changes, when they are severe, you can
see. But you could have 20 or 30 pounds less than normal on a calf
and not realize it’s a copper problem, and that’s the economic
effect which is important.”
In some areas of the
world, copper deficiency also seems to cause reproductive problems
in cattle, says Gay. “Copper deficiency does vary a lot in its
manifestations from one region to another. It may be associated
with other trace element interactions we are not aware of. In our
experience at WSU we haven’t seen reproductive inefficiency. But
if someone phoned me from another part of the country and said
they were having reproductive problems with copper, I would not
discount it. There is always a chance for this--probably more with
molybdenum copper deficiency rather than with primary copper
deficiency,” he says. “There has been some experimental work
showing that it did impair fertility in heifers when they were
given excess molybdenum.” PRIMARY AND SECONDARY DEFICIENCY -
“There are really two types of copper deficiency. One is a primary
deficiency, where the copper levels in the soil and forages are
low. The second type is where the copper concentrations in the
forages might be normal, but the uptake and utilization of copper
in the animal’s body is interfered with by other substances.
Commonly this occurs with the presence of molybdenum, sulfur, and
iron--depending on where you are in the country,” explains Gay.
“In the West, we tend
to have more problem with copper deficiency associated with
molybdenum. This is most prevalent in alkaline soils; the
molybdenum uptake by plants is very much influenced by the pH of
the soil. We have alkaline soils in the West in general, east of
the Cascade Mountains. But as you move farther east, to the
eastern part of the country, soils are more acid. Producers there
run into more problems with primary copper deficiencies than we do
in the West,” he says.
“The other type of soil
that can be a risk factor is peat, or organic soils, and soils
with high water tables. They have a high risk for primary and
secondary copper deficiency, depending on the pH of the soil,”
explains Gay.
“Sulfur, in general,
tends to combine with molybdenum to be a problem. It’s very rare,
but you can find high sulfur by itself causing copper deficiency.
This may occur a bit more in the East than it does in the West,
since it occurs more in acid soils. Where people use lime in
fertilization, they may also use quite high sulfur concentrations,
sometimes with nitrogen, and that can create problems with primary
copper deficiency,” says Gay.
“Iron-induced copper
deficiency is very common in the West in certain areas, such as
west of the Cascades. It tends to be a regional situation. The
main problem for us in the Northwest is molybdenum,” he says.
Molybdenum is often a problem in valley bottoms, or low areas
where water runs down into them from surrounding higher country;
there tends to be more molybdenum in these soils than in the
uplands.
“Even on summer range
in the mountains, the cattle may tend to graze more in the swales
where there are natural springs and greener grass, and that is
often where the problem is, with higher molybdenum levels. The
valley floors are certainly the most likely areas to have
problems, and often have a high water table, too, and more peat or
organic soils,” he says. That can all add up to not being able to
utilize the copper.
“To determine whether
you have a primary or secondary deficiency, you look at pastures.
There’s no point in looking at soils. We take a composite grass
sample, and a composite legume sample, representative of the soil
type. If there are two or three soil types in a pasture or range,
you take samples from each--a composite grass sample and a
composite legume. The reason we take a composite legume sample is
that molybdenum tends to be taken up in higher concentrations in
the legume than in the grass. We look at the copper to molybdenum
ratio. If it is less than 5, you are at risk. If it is less than
2, you can bet that there is a problem. If the copper is at 5 and
there were no interference, it would probably be adequate. But if
you have a molybdenum of 10, you would have real problems.”
He says copper
deficiency is primarily a problem in grazing animals rather than
those being fed hay, since availability of copper is much greater
from hay and other conserved feeds. “Also, mineral/trace element
programs for cattle during the winter feeding period are usually
superior to those on range. Nevertheless, if you are feeding hay
from soil types mentioned above, it may be well worth your while
to have the cattle tested while on those feeds, or to consult with
your nutritionist to ensure an adequate copper content in the
mineral being fed.” HOW TO DETERMINE WHETHER YOU HAVE A PROBLEM -
“If you think you have a problem with weaning weights, you should
test the cattle at that time, before they are weaned and stressed.
When bringing them in to wean, you can blood test them then. There
is some argument as to whether you should use liver or blood
tests,” says Gay. Some people feel that a liver test is the most
accurate.
“We have used blood
tests and found it quite effective; there is no problem with using
this for diagnosis. What you need to do is test at weaning, or if
possible during the summer grazing period, because that’s when we
tend to see the deficiency. If you put cattle onto a problem
pasture in April or May, they will start to show growth depression
by the end of June or beginning of July. At that time, a
proportion of them will show low copper concentrations in the
blood. Other individuals will have normal amounts; there will be a
lot of variation. But if you get out to the end of August or
beginning of September, they will all be very low, if you have a
copper deficiency in the group,” he says.
“You don’t want to test
the cattle early in the grazing season, because the deficiency may
not show up yet. If you think you’ve got a problem, do it in the
middle of the grazing season. Then you have a chance to repair the
deficiency and avoid the weight losses. But usually what happens
is that people test at the end of the summer, when bringing the
cattle off the pasture.” It’s too late then to correct it for
those calves; by then you are looking at doing something to
prevent a similar problem next year.
“Weaning stress,
especially if calves get sick, can disturb copper values. So it’s
best to test them before actual weaning, before they are stressed.
Those tests will at least give you a suggestion as to whether or
not you have a copper deficiency.”
The only true
diagnosis, however, is a response trial, to supplement the cattle
with copper and see if you get better weight gains, he says.
“There are a number of reasons for doing that. Some people who
have said they thought they had copper deficiency, and tested the
cattle (and the tests show they do), and then use a corrective
measure, don’t get a response. Either they didn’t use enough
copper or didn’t give the cattle enough. This is good reason for
checking them again the following year to see if you have, in
fact, repaired the deficiency,” says Gay. TREATMENT - “The
traditional way to deal with copper deficiency is to put copper in
the salt/mineral mix. The problem with that is that you have
variable salt intake through the grazing period. This varies also
from ranch to ranch. So what tends to happen within the herd is
that you have some animals that consume a fair amount of salt and
some who won’t. So you have some that are copper normal, and some
that are still deficient.”
“That is the cheapest
way to go, but isn’t 100 percent effective. The best way we’ve
found is to use copper oxide needles, which to my knowledge are
still available on the market. These are very tiny needles inside
a gelatin capsule. You bolus them down into the rumen. When the
capsule gets down in the rumen the gelatin dissolves and the
needles are released; they lodge in the papillae of the rumen and
sit there for awhile, and gradually pass into the abomasum, where
they dissolve.” The copper thus is released and is made available
for absorption by the body.
“You need to use the
correct dose, however. They were first put on the market 15 years
ago with a dose of 4 grams, which was far too low. You need to use
20 to 25 grams. One bolus, given to an animal at the beginning of
the grazing season, will prevent copper deficiency for 6 months.
In our experience, this has proved to be 100 percent effective,
unless your bolus technique is not good, and the animal spits out
the bolus,” he says.
“The other way to treat
copper deficiency is with chelated minerals, if you want to go
that route. If you think you have a problem, you should obviously
be talking with your veterinarian and nutritionist, for advice in
correction. If you make a corrective measure, it is good to test
the cattle afterward--definitely by weaning time, but preferably
in the August/September period. This is difficult if cattle are on
the range, but you should test them at some time to make sure that
the copper level that you have added is sufficient to correct the
deficiency. There can be great differences in situations. If you
have high molydenum concentrations you are going to need
substantially more copper supplementation than if you have a
simple copper deficiency. The latter is more easily corrected.”
By checking your copper
content in forages (and the ratio of copper to other things that
can interfere with its utilization, like molybdenum), you can
determine how much copper needs to be added into either your
salt/mineral mix or your copper oxide needles given by bolus. You
want to add the right amount in a mineral mix, because if you add
too much it can be toxic, he says.
“Cattle are relatively
resistant to copper poisoning, but sheep are very susceptible. So
if you run sheep, you don’t want to expose them to the copper
supplement given to cattle,” says Gay. Whenever you decide to use
a supplement, it is always wise to consult with a veterinarian and
a nutritionist, to make sure you are on the right track, and to
see which type of supplementation might work best in your own
situation.
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