An experiment was conducted to evaluate the feeding characteristics and the productive responses of lamb diets containing increasing levels of dried brewers' grains (DBG). Five groups of six 70-day-old Bergamasca lambs were housed in individual pens and given ad libitum for 9 weeks pelleted diets containing 200 g/kg of concentrate and 800 g/kg of a mixture of DBG and lucerne hay in the ratios of 0 : 80 (DBG0), 20 : 60 (DBG20), 40 : 40 (DBG40), 60 : 20 (DBG60) and 80 : 0 (DBG80). During the last 12 days of the experimental period, a digestibility trial was carried out for each diet. After this, all the lambs were slaughtered and the composition of the empty body weight was determined. The initial composition of the empty body was estimated from the composition of a sixth group of lambs slaughtered at the beginning of the trial. The apparent digestibility of dry matter (DM), organic matter, crude protein, ether extract, neutral-detergent fibre and energy increased with the proportion of DBG. The daily DM intake relative to metabolic body weight (M0.75) diminished significantly with the increasing proportion of DBG in the diet, from 127 g/kg M0.75 for diet DBG0 to 83 g/kg M0.75 for diet DBG80. The daily live-weight gain and food DM conversion efficiency were highest with the intermediate diets (414 g/day with diet DBG40 and 240 g/kg DM with DBG60), showing a quadratic trend, an indication of a positive interaction between DBG and lucerne hay. The fat content of the live-weight gain was particularly high in the lambs given the diet with the highest proportion of DBG. It was concluded that DBG may be profitably used in growing-fattening diets for lambs in a proportion not exceeding about 400 g/kg DM.
