RESUMO
Copper toxicity was observed when crossbred cows were injected with 480 mg copper sc. Five head died after copper disodium EDTA (edetate) injections but no losses occurred with copper glycinate. Necropsy, histopathology and plasma enzyme values indicated severe hepatic necrosis in the affected cattle. Plasma copper levels peaked 2 hr postinjection (3.82 micrograms/ml) in cattle that lived after EDTA injections, but about half this level (2.00 micrograms/ml) of copper was observed in the animals that died and 0.65 in the glycinate-treated animals (P less than .01). Ceruloplasmin levels were low in all cattle (2.1 to 7.2 IU/L). Plasma iron increased between 2 (179 micrograms/dl) to 4 (422 micrograms/dl) hr after injection for all cattle and remained high at 8 hr (501 micrograms/dl postinjection; P less than .01). After copper was administered, plasma zinc decreased 45 to 75% of pre-injection levels (P less than .01). Plasma urea nitrogen was not modified by the treatments. Hemolysis was not observed in any of the animals.
