Ben-Ghedalia, D., Institute of Animal Science, ARO, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Miron, J., Institute of Animal Science, ARO, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Est, Y., Institute of Animal Science, ARO, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Yosef, E., Institute of Animal Science, ARO, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel

Thirty-nine male lambs of the Assaf dairy breed were assigned shortly after weaning, at 17.5 kg liveweight, to one of the following three nutritional treatments: I, a high energy concentrate mixture (CD); II, a diet in which 60% of the concentrate was replaced by a combination (1:1) of wheat straw+poultry litter containing 100 ppm copper (UTS) and III, as II, but the straw was treated with 3.5% sulfur dioxide at 70°C for 72h (SO2-TS). The diets were fed ad libitum for the entire growth experiment, which lasted 110-117 days. Daily gains were 266, 356 and 363 g for the UTS, SO2-TS and CD rations, respectively. The SO2-TS lambs were leaner than those of the CD ration and their meat was accepted well. Sulfur dioxide-treated straw and poultry litter are suggested as complementary feeds and when given in a 1:1 combination can replace 60% of the concentrate in intensive-growth lamb rations. Dietary SO2-treated straw exerts a protective effect against copper toxicity in high-copper lamb diets. © 1988.