Abstract
Two experiments were conducted on D'Man ewes. Date palm by-products (DPB) are whole dates rejected for human consumption. A total of 11 DB varieties were sampled and analyzed. In Exp. 1, suckling ewes (n=20) were used during 90 d to compare a control diet to a DPB diet. Whole or seedless DB nutritive composition, feed intake and lamb BW were measured. In Exp. 2, concentrate was progressively substituted by the DPB mixture during 21 d in 12 ewes. The initial daily offer of DPB was 0.4 kg and the final was 0.7 kg with an increase rate of 50 g every 3 d. The composition of DB changed according to the variety, the rangesbeing : CP (1.99 to 4.50%), NDF (10.52 to 26.05%) and ADF (7.15 to 21.96%). Whole DB have higher contents than seedless DB: CP (3.24 vs. 2.88%), NDF (18.11 vs. 13.93%), ADF (13.01 vs. 9.77%) and ADL (5.99 vs. 5.63%), with a 5% net energy difference (1.92 vs. 2.02 Mcal NEL/kg DM, P=0.071). In Exp. 1, lambs ADG between 10 and 45 d, did not vary according to feeding treatment (C, 113+22; DB, 128+13 g/d). In Exp. 2, ewes feed intake decreased as the rate of concentrate substitution by DB increased. Total daily intake decreased from 1.64 to 1.31 kg from the beginning to the end of the experiment, as a consequence of the decrease of hay intake (0.24 kg/d) and refusing of DB seeds (0.093 kg/d). In conclusion, DPB can substitute concentrate at a minimum rate of 25% in sheep diets, although fill value increases with DB incorporation.