a1 Department of Animal Science, University of Natal, PO Box 375, Pietermaritzburg, 3200, South Africa
Lambs were allocated to three treatments: control (C), monensin (M) and lasalocid sodium (L) in a concentrate diet containing 36 mg copper per kg food. After 2 months deaths from copper toxicity occurred and the trial was terminated. All lambs were slaughtered. The mean liver copper concentration (mg/kg dry matter) of 1907 in the M treatment was higher than the mean concentrations of 1342 and 1229 in the C and L groups respectively (P < 0·01). Total liver copper was 234, 260 and 230 mg and the retention of dietary copper in the liver was 93·5, 108·5 and 93·3 g/kg for the C, M and L treatments respectively. These differences were not significant. From reduced liver size (as a proportion of body weight) and high copper levels in the kidneys, it was concluded that the group given monensin had accumulated copper to a level closer to the toxicity threshold than the other two groups.
(Received August 13 1986)
(Accepted October 06 1986)