Reviewed April 07
Trace element deficiencies in sheep and
By Tony Higgs, Senior Veterinary Officer, Albany
The trace elements of concern to livestock producers in
Poor paddock drainage will increase cobalt and selenium
Western Australia are cobalt, selenium and, to a lesser
uptake by pasture but reduce copper availability.
extent, copper. Trace element deficiencies are seen
mainly in the higher rainfall areas of the south-west,
particularly along the coast.
The trace mineral concentration in plants is reduced by
the dilution effect of rapid growth during spring. Higher
Pasture growth and persistence requires adequate
levels of sulphur in green feed may reduce the availability
copper in the soil. Pasture copper levels that are
of copper and selenium.
adequate for plant growth will also be high enough for
livestock. However, excessive iron, molybdenum and
sulphur levels will reduce the amount of copper that is
Stress will increase the effect of a deficiency and, in the
available to ruminants.
case of selenium deficiency, may trigger clinical disease.
Cobalt is required in minute amounts by bacteria that fix
An animal’s trace element needs increase during
nitrogen in legumes, but livestock requirements for cobalt
pregnancy, lactation and growth.
are higher. Cobalt is essential for the production of
vitamin B by rumen microbes. Selenium is not an
essential nutrient for plants, but it is needed to maintain
Rotational grazing will increase an animal’s chance of
animal health and production.
correcting a trace element deficiency. Subtle differences
Obvious clinical disease from trace element deficiencies
between paddocks may mean that trace elements are
is less frequent now than in the past. The cause and
more available in some than others.
distribution of these deficiencies have been extensively
studied, practical solutions have been developed and the
Deficient areas in Western Australia
information is widely available. There are many options
available to farmers to prevent deficiencies.
Copper is recommended for all new land in the south-
The more recent interest in trace elements has been to
west of the state but recommendations on repeat
find out whether supplementation will improve production
applications have changed steadily since the 1940s.
as well as prevent disease.
Current research suggests that there is no decline in the
residual effectiveness of copper fertiliser up to 25 years
Factors affecting the trace mineral
after application. This period is likely to be extended after
nutrition of livestock
Excessive soil levels of molybdenum will induce a
Although the soil level of each trace element is important,
secondary copper deficiency by combining with copper
there are several complex interactions that can affect the
and sulphur in the rumen to form the insoluble product
availability of an element to pasture plants. Generally,
copper thiomolybdate. Also, some molybdenum is
liming (increasing pH) decreases plant uptake of cobalt
absorbed by the animal and then directly affects the
but increases selenium and molybdenum uptake.
function of copper. Excessive use of molybdenum
fertilisers should be avoided. One application of 75 g/ha
Pasture composition also influences trace element
of molybdenum will be adequate for 10 to 15 years on
availability. Clover plants are less efficient at taking up
slightly acidic soils (pH 6.0 to 6.9). More frequent
selenium than grasses but more efficient at taking up
applications (within three years) may be required on acid
cobalt and copper.
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by reason of negligence or otherwise arising from the use or release of this information or any part of it.
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soils (pH 4.0 to 5.0). Often the best way to correct a
Clinical signs in cattle
molybdenum deficiency in the pasture is to lime. If
molybdenum is applied to the pasture do not allow cattle
to graze until after heavy rain.
Cattle lose coat colour and the coat becomes rough. This
can occur in the absence of any production losses. The
classical spectacled appearance may occur, where the
Cobalt deficiency is seen in areas receiving more than
hair around the eyes loses its pigmentation.
450 mm of rainfall. Soil types derived from acid igneous
Ill-thrift, decreased milk production, infertility and
rocks such as granite (karri loams) and those subject to
anaemia can occur in adults, and calves have poor
leaching (banksia and tuart sands of the west coast) are
growth rates. Scouring is often associated with copper
frequently associated with deficiency, as is intensively
deficiency caused by high levels of dietary molybdenum
cropped land. Cobalt deficiency can be seen in
but not when a deficiency is due mainly to low dietary
association with heavy liming of pasture.
copper. Sudden death (falling disease) may occur in
Selenium deficiency is seen in areas receiving more than
410 mm of rainfall, particularly on lighter soil types. The
A wasting syndrome develops similar to that seen in
higher the rainfall the worse the deficiency, because of
sheep. There is a greater susceptibility to other diseases
leaching and the degree of spring flush. Low vitamin E
such as mucosal disease, ostertagiasis and mange.
levels may be associated with a selenium deficiency
when pastures are dry.
Clinical signs in sheep
Suckling calves may develop nutritional myopathy, which
usually affects heart muscle and consequently causes
sudden death. Ill-thrift may occur in young cattle. Limited
Abnormalities of the wool (loss of crimp, steeliness and
evidence suggests that a marginal deficiency reduces
depigmentation) are seen in the early stages of copper
milk volume, fat yield and conception rates, and
deficiency. Anaemia, scouring, ill-thrift and infertility may
increases the occurrence of retained foetal membranes
occur in extreme cases. Bone fragility in lambs can occur
in spring. Affected animals develop fractures of the ribs
Differences between sheep and cattle in
and limbs. Unweaned lambs may develop a condition
susceptibility to a deficiency
known as enzootic ataxia in which lambs up to four
months old progressively lose coordination in their hind
The copper requirement for cattle is slightly higher than
for sheep. Falling disease has been seen in cattle when
there were no signs in sheep.
Cattle are less at risk from cobalt and selenium
Sheep suffering from cobalt deficiency gradually lose
deficiencies than sheep.
their appetite and fail to thrive. Continued deficiency
leads to signs of prolonged malnutrition due to the effect
of anorexia and impaired nitrogen metabolism. The
disease is most common in spring and early summer.
Growth, lactation and wool production are severely
To assess the likelihood of deficiencies, results of soil
retarded and wool may be tender or broken. Anaemia
tests for trace minerals must be adjusted for soil type, the
may occur late in the disease. White liver disease has
presence of competing minerals, the plant species
occurred in Western Australia. Weeping eyes, leading to
growing in the area and seasonal conditions.
matting of the wool on the face, is a classic symptom of
Consequently, soil testing is an indirect measure of the
trace mineral status of grazing livestock and is of limited
Deficiencies of selenium and/or vitamin E cause
nutritional myopathy in lambs (in autumn and winter) and
Plant testing may be useful in the diagnosis of copper
weaners (in summer and autumn). The disease affects
deficiency, particularly to determine the likely role of
heart and skeletal muscle and is often associated with
molybdenum and sulphur. However, take great care
some other stress such as shearing, salty water
when interpreting pasture levels of cobalt and selenium,
supplies, lupinosis or heavy worm burdens. Affected
especially when results are at marginal levels.
stock may have a stiff gait, or be unable to walk. Some
may go down when driven and die soon afterwards.
Heart damage can cause sudden deaths.
comes from a study where sheep were monitored on one
severely cobalt deficient property over 14 consecutive
Animal tissue levels are a better guide than results from
years. The sheep showed a response to cobalt
soil and plant tests but animal tissue results must be
supplementation in nine of those years.
considered together with the case history and the clinical
signs. Part of the history will include the time of year
when the suspected deficiency started and the prevailing
seasonal conditions. Animal tests may be useful for
detecting an emerging trace element problem.
Three trials in the Albany region and one at Newdegate
Response to treatment remains the most effective test
showed no production response but clinical copper
for trace mineral deficiencies. It is also the most effective
deficiency continues to be diagnosed as a cause of
method for determining the presence of a marginal
production loss. In the past two years cases have been
diagnosed in association with ill-thrift in near coastal
areas from Geraldton to Mt Barker.
Responses to supplementation — trial
Responses to trace mineral supplementation in deficient
Four of 34 trials conducted from Dongara to Esperance
areas are unlikely to occur in successive years and local
showed a response to cobalt supplementation. These
information suggests that responses are likely once in
responses occurred on grass dominant pastures in
every three years. An example of between year variation
spring after above average winter rainfall.
Table 1. Cost of different methods of trace element supplementation, based on average retail prices
(excluding GST) at Albany in February 2004.
(every 10 y)
Injection - cattle
1 mL (calves)
$0.25 (2 doses)
2 mL (adults)
$0.50 (2 doses)
Cobalt sulphate with
Cobalt sulphate sprayed
1 for life (5 y)
Vitamin B12 injection without
1 mL/3 months (lambs)
$0.16 (2 doses)
1 mL/y (adult sheep)
$0.08 (1 dose)
2 mL/2 months (cattle)
$0.47 (3 doses)
Vitamin B12 injection
1 mL/3 months (lambs)
$0.20 (2 doses)
1 mL/y (adult sheep)
$0.10 (1 dose)
2 mL/2 months (cattle)
$0.60 (3 doses)
(applied with fertiliser)
1 for life (5 y)
5 mL (lambs)
$0.14 (5 doses)
20 mL (ewes)
Selenium with vaccine#
2 mL (lambs)
$0.04 (2 doses)
2 mL (sheep)
$0.02 (booster dose)
5 in 1 (cattle)
2 mL (calves)
$0.10 (2 doses)
2 mL (cattle)
$0.05 (booster dose)
* Assuming a stocking rate of 10 DSE/ha
# Selenium supplementation by this treatment method is effective for approximately 8–12 weeks
There are several methods for supplementing with trace
elements. A guide to the cost of different methods is
Responses in liveweight and wool growth have been
given in Table 1. One way to reduce costs is to include
seen in zones with annual rainfall above 410 mm. Trials
an assessment of the risk for each season. For example,
from 1960 to 1982 conducted in the Albany region, with
in a season with a good break, heavy winter rains and a
rainfall over 500 mm, showed significant production
good spring flush, there is a greater probability that
responses at nine of 27 sites. Only one significant
cobalt will be deficient. In this situation, cobalt sulphate
increase (10 per cent) in lambing percentage was
could be sprayed onto pastures being grazed by young
recorded from 26 other trials.
The cause of a copper deficiency should be determined.
In 25 trials on farms with suspected copper deficiency,
Check the pasture levels of copper and molybdenum
only one produced a growth response after copper
and correct them as necessary. Animal treatment may
supplementation. Studies conducted elsewhere suggest
be required in the short term, before pasture copper and
that responses to supplementation are more likely when
molybdenum levels can be corrected. In the case of
the copper deficiency is due to excessive dietary
excessive pasture molybdenum, animal treatment may
be required over several seasons. In the latter situation,
slow release copper supplements given orally may be
more effective than injectable copper formulations.
One small response to cobalt supplementation was seen
in cattle liveweights in one of four years (1973–1976) at
Pasture treatment by foliar spray is the cheapest method
of supplementation. Reduce costs further by treating the
In a subsequent trial in 1977, growth rates were greater
parts of paddocks that will carry young stock at a
in supplemented cattle. Trials on 13 other properties from
proportionately higher concentration.
Bunbury to Esperance showed no response.
Pellets are a cheap method for sheep but the life of the
Four trials were conducted in the Albany region in 1976
pellet may be only one to two years, which may be
and 1977 in calves less than six months old. Liveweight
inadequate for lambs suckling mature ewes.
changes were not significant.
Pasture treatment may be a better option. Areas that
Four trials on 11 farms in the Bunbury region did not
carry young sheep or cattle may be targeted for
produce significant liveweight changes. A more recent
treatment, or part of the farm could be treated and stock
study in dairy cattle indicated that selenium
rotated through the treated areas. Recent studies
supplementation reduced the incidence of new udder
indicate that slow release selenium fertiliser may provide
infections. Nutritional myopathy has been recorded in
adequate selenium for grazing stock for three years.
cattle, mostly suckled calves, from Moora to Esperance.
Care should be taken to avoid over supplementing with
selenium. The use of selenium pellets and treatment of
the pasture at the same time can lead to excessive tissue
The decision to implement a trace element
levels in sheep.
supplementation program is relatively simple for
properties that have a known history of clinical disease.
If a deficiency is identified, then it is likely to occur again
in future years unless preventive measures are taken.
Farmnote No. 25/88 “Copper, zinc and molybdenum
fertilisers for new land”
On properties that have no record of clinical disease but
which are in areas that are known to be deficient, the
Farmnote No. 80/89 “Avoiding cobalt deficiency in
decision whether to use trace elements is more difficult.
The best approach is to conduct a production response
Farmnote No. 7/92 “Mineral requirements of the lactating
trial. Regrettably, it is the nature of trace element
deficiencies that a response may only be seen once
every few years, so trials must be run over several years.
Farmnote No. 15/94 “Copper deficiency in sheep and
If a response is found, the selection of a supplementation
option should be based on economics.
© State of Western Australia, 2004.