Effect of zinc and molybdenum supplementation of the feed concentrate on the storage of copper in the liver of lambs

Summary During a 98-day trial, eight groups of eight male weanling Texel x Friesian milk sheep lambs were fed the same hay and concentrates, the latter differing only in the contents of Cu, Zn, and Mo. At high (± 30 ppm) and moderately low (± 15 ppm) copper levels in the concentrates, additions of Zn (respectively 0, 150, and 340 ppm) and Mo (0 and 16 ppm) to the concentrates were studied with regard to effect on the accumulation of copper in the liver. At the higher copper level, the addition of 150 or 340ppm Zn resulted in a significant decrease of the Cu accumulation in the liver, while at a moderately low copper level the effect of these additions on the Cu accumulation was only slight. The two Zn doses given appeared to be equally effective in reducing the Cu accumulation. Additions of zinc did not increase liver and kidney Zn. The addition of Mo. resulted in higher levels of Mo in liver and kidney. At either copper level the addition of 16 ppm Mo was more effective in reducing the Cu accumulation in the liver than the addition of 150 or 340 ppm Zn. The additions of Zn and Mo, had no visible influence on the health of the lambs. This agrees with the finding that the blood parameters (determination of haemoglobin, haematocryt, protein, copper, zinc, enzymes) and the growth of the lambs were in the normal range. These results suggest that zinc may be a useful alternative to the somewhat toxic molybdenum as an additive to concentrates for sheep in preventing Cu intoxication.