An assessment of the toxicity of parenteral treatment with copper EDTA and copper heptonate in sheep.

The toxicity of 2 parenteral copper (Cu) supplements was investigated. Di-sodium copper ethylene diamino tetra acetate (Cu EDTA) and Cu heptonate were administered to sheep (n = 9) by a single subcutaneous injection at a concentration of 0,2, 1 and 2 mg Cu/kg each (Trial 1.) Nine sheep were untreated and served as controls. The same treatments were applied to 2 sheep each (Trial 2) with the addition of 3 mg Culkg live body mass as Cu heptonate, and Cu heptonate administered intravenously at rates of 0,2, 0,4 and 0,6 mg Culkg live body mass. In Trial 1, 67 % of the sheep treated with Cu EDTA at 2 mg Culkg live body mass died within 3 to 17 dafter treatment, while no mortalities occurred in sheep where Cu heptonate was administered at the same dosage rate and even at 3 mg Culkg live body mass (P ~ 0,01). Post-mortem examination suggested acute Cu toxicity in all cases. Liver Cu concentrations were markedly increased (P ~ 0,05) by both supplements in groups of 3 treated sheep slaughtered over a 3-month period compared to control animals. The liver Cu concentrations of sheep that succumbed to Cu toxicity were within the normal range of 100 to 450 mglkg DM. Results from Trial 2 suggested that the 2 sheep treated with 2 mg CuIkg live body mass as Cu EDTA,.experienced a haemolytic crisis between 5 and 11 d after treatment, resulting in the death of one of these sheep. The haemolytic crisis was characterised by a severe decrease in haemoglobin concentration and haematocrit. Sheep treated with Cu heptonate did not show any indications of similar complications, even when given 3 mg Cu/kg live body mass subcutaneously or 0,6 mg Culkg live body mass intravenously.