Copper is an essential trace mineral for livestock but can also cause toxicity issues in sheep. Sheep are highly susceptible to copper toxicity due to their lower copper tolerance compared to goats. Raising sheep and goats together requires special consideration of copper nutrition to avoid deficiencies in goats or toxicity in sheep. Copper toxicity may occur from excessive intake in feed, water, or mineral supplements and is diagnosed through clinical signs, laboratory tests, and determining copper levels in the diet. Treatment focuses on reducing copper intake and providing antagonists like molybdenum and sulfur. Copper deficiency can also occur from primary dietary deficiencies or interactions with other minerals and is treated with copper injections or oral supplements. Copper sulfate and copper oxide

1. Copper deficiencies
and excesses
SUSAN SCHOENIAN AND JEFF SEMLER
UNIVERSITY OF MARYLAND EXTENSION

2. Copper (Cu)
Why we think it’s an important topic.
• Sheep are very susceptible
to copper toxicity.
• Sheep and goats differ
significantly in their copper
requirements and
tolerance for excess
copper in their diet.
• Raising sheep and goats
together presents some
challenges from the
standpoint of copper
nutrition.

3. Copper (Cu)
Why we think it’s an important topic.
• “Copper” is being
recommended (again)
as an anthelmintic.
• Some books and
people are
recommending that
copper be added to
sheep diets.
• Copper nutrition is
complex because of
its interaction with
other minerals.

4. Importance of copper (Cu)
Copper is a trace mineral that is a dietary essential.
Hemoglobin formation
Involvement in enzyme systems
Nerve function
Cardiovascular integrity
Bone structure
Connective tissue formation
Fertility and reproduction
Immune function
Protection against superoxide radicals
Pigmentation and hair texture

5. Copper basics: plants
• Fresh grasses are poor sources
of copper.
• Acidic soils increase Cu and
lower Mo in forages.
• Mo is higher in alkaline or high
organic matter soils.
• Copper absorption in plants is
limited by alkaline pH or higher
organic matter.
• Liming can increase Mo in
forage and disturb the Cu:Mo
ratio (Cu:Mo ratios of at least
are considered safe and will
avoid copper deficiency).
• Copper-containing fertilizer can
increase copper levels in plants
(e.g. poultry/pig manure).
Soil ingestion can increase intake of copper.

6. Copper status of forages

7. Copper basics: animal
• Copper is absorbed from the
small intestines.
• Absorbed copper in excess of
requirements in stored in the liver
(a small amount is removed by
the kidneys).
• When net copper absorption is
insufficient to meet metabolic
requirements, liver stores are
mobilized.
• If the concentration of copper in
the liver exceeds a certain critical
value, there may be a sudden
release of massive amounts of
copper into the bloodstream, with
potentially deadly consequences.

8. Copper absorption
• More important than its
concentration in feed.
• Affected by species,
breed, genetics, and age.
• Young ruminants absorb
Cu more efficiently.
• 70-75% (up to 90%) absorption
in young ruminant vs. > 10% in
mature ruminants.
• Copper crosses placenta, but
only a small amount is
secreted in the milk.
• Ionophores increase efficiency
of copper absorption.

9. Copper absorption is affected by
other minerals in the diet
• Molybdenum (Mo) and
sulfur (S) form insoluble
complexes with Cu and
prevent its absorption.
• Cu absorption is
decreased when there is
excess zinc (Zn) and iron
(Fe) in the diet.
• Cu absorption can also
be affected by cadmium
and vitamin C.

10. Copper requirements
SHEEP GOATS
Cu requirement Reference Cu requirement Reference
5 mg/kg NRC, 1975 8-10 mg/kg 1991, 2000
1 - 8.6 mg/kg ARC, 1980 10-23 mg/kg 1992
7-11 mg/kg NRC, 1985 10-23 mg/kg 1997
4.3 – 28.4 mg/kg 1999
15 mg/kg*
lactating goat NRC, 2007
Equations which use different absorption
coefficients of copper and variable levels 20 mg/kg* *Adjustments
of absorption antagonists and metabolic mature goats and bucks should be made
interactions are used to calculate the for the level of Mo
25 mg/kg* and S in the diet.
copper requirements for different classes
growing goats
of sheep (NRC, 2007).
Maximum tolerable level: 15 mg/kg A maximum tolerable level has not
when diets contain normal Mo (1-2 been established for goats. Cattle
mg/kg and S (0.15-0.25 percent). level is 40 mg/kg.

11. Copper excesses and deficiencies
+
GOATS
• More likely to experience
SHEEP copper deficiency.
• More likely to experience • Goats have a higher
copper toxicity. requirement and
• Sheep are the species tolerance for excess
most susceptible to copper as compared to
copper toxicity. sheep.
(-)
• There is a narrow
margin between
requirements and
toxic levels.

12. Two forms of copper toxicity
ACUTE CHRONIC
• Caused by ingestion of • High levels of copper are
high copper feeds, salts, ingested over time, but
pesticides, poultry litter, at levels below the
or other high copper acutely toxic level.
substances. • Usually occurs when
• Can occur at intakes of there is a high
20-100 mg/kg (or ppm). Cu:Mo ratio.
• Stress is usually
the trigger.

13. Two phases of copper toxicity
PRE-HAEMOLYTIC HAEMOLYTIC
• When copper • When copper is
accumulates in liver released from the
to exceed 1000 mg liver and blood
Cu/kg DM copper values rise.
• Lasts from weeks to • Lasts from hours
more than a year. to days.
STRESS

14. Diagnosis of copper toxicity
1. Clinical signs
2. Laboratory tests
3. Necropsy
4. Determine
mineral
concentrations of
the diet and
other potential
sources of
excess copper.
Texel sheep are more susceptible to Cu toxicity.

15. Diagnosis of copper toxicity
Clinical signs
• Weakness
• Panting
• Dullness
• Pale mucous
membranes
• Yellow discoloration
(jaundice) of mucous Images from Colorado State University
membranes
• Dark brown or red-
colored urine
• Abortion
• Death

16. Diagnosis of copper toxicity
Laboratory tests
• Liver copper
• Kidney copper
• Blood level
• Serum
• Plasma
• Liver enzymes

17. Diagnosis of copper toxicity
Necropsy
Images from Colorado State University
Icterus (jaundice) “gun, metal, blue” kidneys

18. Diagnosis of copper toxicity
Determine mineral concentrations in diet
1. Copper
2. Molybdenum
3. Sulfur
4. Iron

19. Common sources of excess copper
• Errors in feed formulation
and mixing
• Consumption of feedstuffs
formulated for other animals.
• Consumption of non-traditional
feedstuffs that are high in
copper.
• Grazing on pastures fertilized
with pig or poultry manure.
• Grazing forages deficient in
molybdenum.
• Use of copper-containing
anthelmintics.
• Use of copper-containing
footbaths.
• Copper supplements.

20. Treatment of Cu toxicity
• Usually unrewarding
for severely-affected
animals.
• Administer both
molybdenum and
sulfate as a drench or
add to feed.
• Ammonium molybdate
• Sodium sulfate
• Reduce or eliminate
extraneous sources of
copper.

21. Copper deficiency
Common causes
1. Primary
• Low intake of copper
• Fresh forages have less
Cu than cured hays.
• Grasses has less Cu
than legumes
• Liming reduces Cu
uptake by plants.
2. Secondary
• High concentrations of
Mo, S, Fe, Cn, Se, and
ascorbic acid (vitamin C).
• Alkaline soils

22. Diagnosis of copper deficiency
1. Clinical signs
2. Lab tests
3. Necropsy
4. Determine mineral
concentrations of
the diet.
5. Clinical response
to copper
supplementation.

23. Diagnosis of copper deficiency
Clinical signs
• Anemia
• Reduced growth rate
• Connective tissue
disorders
• Generalized osteoporosis
• Increased susceptibility
to all diseases.
• Neonatal or congenital
ataxia (swayback)
• De-pigmentation of skin,
hair, or wool.
• Loss of crimp, steely or
stringy wool

24. Treatment of copper deficiency
• Injectable copper
(can cause tissue damage)
• Oral copper
(short-acting)
• Copper oxide
particles
• Mineral supplement
• Copper-containing
fertilizers.

25. Copper as an anthelmintic
1. Copper mineral
supplement
2. Copper sulfate
(Cu2SO4)
3. Copper oxide wire
particles (COWP).

26. Copper sulfate (Cu2SO4)
• Historical dewormer used
in the early 1900’s before
synthetic dewormers
became available.
• Was often combined with
lead arsenic or nicotine
sulfate to broaden its
efficacy.
• Due to the widespread
development of drug-
resistant worms, copper
sulfate is being re-
evaluated as a dewormer.

27. Copper sulfate (Cu2SO4)
• Usually administered as a 1-1.5
percent solution in water.
• How copper sulfate compares to
a synthetic dewormer depends
upon the degree of resistance to
the synthetic dewormer.
• Recent research has shown that
copper sulfate can be effective
at reducing fecal egg counts
without causing copper toxicity.
• When/if used, copper sulfate
should only be administered to
clinically-parasitized animals.
• Copper toxicity is always risk if
copper sulfate is not administered
properly, especially to sheep!

28. Copper oxide
• Slow dissolving form of
copper.
• Not absorbed as well as
copper sulfate.
• Sold as a supplement to
treat or prevent copper
deficiency in cattle.
• Cattle doses need to be
re-sized for sheep and
goats.

29. Copper oxide wire particles
• Recent research has
shown COWPs to be as
effective as most
anthelmintics in reducing
fecal egg counts.
• However, COWPs are
only effective against the
barber pole worm.
• COWPs seem to be more
effective on young stock.
• Their exact mode of
action is not known.

30. Copper oxide wire particles
• Experts disagree as
to whether to
recommend COWPs
as an anthelmintic
for sheep.
• Most research has been
done with hair sheep and
goats.
• There hasn’t been any
copper toxicity in research
studies.

31. Copper oxide wire particles (COWPs)
Recommendations
• No problem using COWPs in
goats.
• Do not use in sheep unless
you have total anthelmintic
failure or you are a certified
organic producer.
• Check with inspector to see if
COWPs would be allowed as a
dewormer.
• Only administer COWPs to
clinically-parasitized animals
(FAMACHA© 3-5).
• Since copper accumulates in
the liver over time, limit the
use of COWPs to lambs that
will be going to slaughter.

32. Raising sheep and goats together
Copper presents a dilemma.
• Feeding sheep mineral
(low copper) to sheep
and goats increases
the risk of copper
deficiency in goats.
• Feeding goat mineral
(higher copper) to
sheep and goats
increases the risk of
copper toxicity in
sheep.

33. Raising sheep and goats together
Copper poses a problem.
• Feed them
separately.
• House them
separately at night
• Put mineral feeder
for goats where
sheep can’t get it.
• Give goats copper
supplements, e.g.
boluses.

34. Questions? Thank you for your attention.