Industrial Copper Intoxication of Iranian Fat-Tailed Sheep in Kerman Province, Iran

Copper Poisoning, a Deadly Hazard for Sheep

“…Cu intoxication is a global problem and concerns several sheep-rearing countries, such as Scandinavian countries, Canada, Australia, New Zealand, United Kingdom, USA and South Africa [ 6 , 11 , 31 , 33 ]. In addition, several outbreaks and cases have been described in other countries such as Spain [ 17 ], Brazil [ 15 , 31 , 34 ], Greece [ 35 , 36 ], Iran [ 37 ] and Turkey [ 38 , 39 ]. With respect to the production system, CCP is more frequent in intensive indoor conditions, housed lambs or milk sheep fed with large amounts of concentrates [ 12 , 30 , 35 ], and rarely occurs in grazing sheep under natural conditions, except in susceptible breeds or when pastures are contaminated with Cu or have very low levels of Mo [ 12 ].…”

“…In addition, errors in the formulation of rations or in the mixing of feed and the administration of feed formulated for Cu-tolerant species (especially swine and poultry feed being supplemented with Cu) can cause Cu poisoning in sheep [ 5 , 8 , 10 , 31 , 35 , 42 ]. Other sources of Cu include Cu-contaminated feedstuff, such as forage sprayed with fumigants or fungicides [ 10 , 16 , 38 ], pasture fertilised with swine manure slurry and poultry litter, which may also be ingested accidentally [ 5 , 10 , 35 , 43 ], or vegetation and soil contaminated as a result of industrial and mining activities [ 10 , 17 , 35 , 37 , 44 ]. The ingestion of Cu sulphate footbaths, water contaminated with fungicides, algaecides, molluscicides or containing Cu dissolved from pipping, and the use of ruminal boluses with Cu wires which can release Cu slowly, can be other sources of oral exposure to the element [ 5 , 8 , 15 , 16 , 38 ].…”

“…Subsequently, the kidney can be damaged by the Cu accumulation and the direct toxic effects of haemoglobin released following the red blood cell lysis, causing acute tubular injury [ 8 , 10 , 63 ]. Furthermore, degeneration of white matter in the brain and central nervous system gliosis can be developed [ 10 , 16 , 31 , 37 , 64 , 65 ]. Cu seems to cause status spongiosus in the sheep’s central nervous system as a result of altered glial transport mechanisms [ 64 , 65 ].…”

“…The following can be observed: pale mucous membranes, icterus, depression, weakness, recumbency, anorexia, excessive thirst, dyspnoea, arched back due to renal pain, as well as reddish brown to dark brown urine due to haemoglobinuria, and death after 24–48 h [ 5 , 8 , 10 , 16 , 30 ]. In addition, tachycardia, irregular pulse, tachypnoea, incoordination, ptyalism and nervous signs, such as blindness, tetraparesis, dementia and aggression, can be found in sheep suffering CCP [ 16 , 36 , 37 , 38 , 43 , 65 ]. Haywood et al [ 66 ] described a CCP outbreak in which abortions, stillbirths and weakly lambs that often failed to thrive occurred in association with haemolytic crises.…”

“…In the haemolytic phase, haematological findings typical of acute haemolytic anaemia are observed, with a sharp reduction in the packed cell volume (PCV), which can go down to values around 10% [ 43 ], red blood cell (RBC) count and haemoglobin, as well as macrocytosis, hypochromasia and basophilic stippling [ 16 , 30 , 37 , 42 , 43 , 65 ], which are common RBC abnormalities in regenerative anaemia of small ruminants [ 62 ]. Heinz bodies and methaemoglobinemia have also been referred [ 16 , 35 , 37 , 43 , 68 ], which can appear in haemolytic anaemias from oxidant injury to RBCs, in this case caused by the sudden increase in blood Cu concentrations [ 22 , 62 ].…”