Copper deficienciesand excessesSUSAN SCHOENIAN AND JEFF SEMLERUNIVERSITY OF MARYLAND EXTENSION
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.
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.
Importance of copper (Cu)Copper is a trace mineral that is a dietary essential.Hemoglobin formationInvolvement in enzyme systemsNerve functionCardiovascular integrityBone structureConnective tissue formationFertility and reproductionImmune functionProtection against superoxide radicalsPigmentation and hair texture
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.
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.
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.
Copper absorption is affected byother 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.
Copper requirements SHEEP GOATSCu requirement Reference Cu requirement Reference5 mg/kg NRC, 1975 8-10 mg/kg 1991, 20001 - 8.6 mg/kg ARC, 1980 10-23 mg/kg 19927-11 mg/kg NRC, 1985 10-23 mg/kg 19974.3 – 28.4 mg/kg 1999 15 mg/kg* lactating goat NRC, 2007Equations which use different absorptioncoefficients of copper and variable levels 20 mg/kg* *Adjustmentsof 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 notwhen diets contain normal Mo (1-2 been established for goats. Cattlemg/kg and S (0.15-0.25 percent). level is 40 mg/kg.
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.
Two forms of copper toxicityACUTE 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.
Two phases of copper toxicityPRE-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
Diagnosis of copper toxicity1. Clinical signs2. Laboratory tests3. Necropsy4. Determine mineral concentrations of the diet and other potential sources of excess copper. Texel sheep are more susceptible to Cu toxicity.
Diagnosis of copper toxicityClinical 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
Diagnosis of copper toxicityNecropsy Images from Colorado State University Icterus (jaundice) “gun, metal, blue” kidneys
Diagnosis of copper toxicityDetermine mineral concentrations in diet1. Copper2. Molybdenum3. Sulfur4. Iron
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.
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.
Copper deficiencyCommon 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
Diagnosis of copper deficiency1. Clinical signs2. Lab tests3. Necropsy4. Determine mineral concentrations of the diet.5. Clinical response to copper supplementation.
Diagnosis of copper deficiencyClinical 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
Treatment of copper deficiency • Injectable copper (can cause tissue damage) • Oral copper (short-acting) • Copper oxide particles • Mineral supplement • Copper-containing fertilizers.
Copper as an anthelmintic1. Copper mineral supplement2. Copper sulfate (Cu2SO4)3. Copper oxide wire particles (COWP).
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.
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!
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.
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.
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.
Raising sheep and goats togetherCopper 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.
Raising sheep and goats togetherCopper 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.