This study was conducted to investigate the effects of feeding spent wheat
straw (SWS). a by-product of mushroom cultivation ad lib, with different concentrate
levels (70. 60 and 50% from TDN requirement) on digestibility and performance of
ewes and their lambs during gestation and suckling periods, Twenty four cross-bred
pregnant ewes (Suffolk x Osslmi) about 63 kg in weight and 2.5 - 3 years in age were
used. The animals Wars divided according to theit body weights into 4 groups (6 in
each). to evaluate the following rations: Ration (A): 70% of TON requirement from concentrate feed mixture (CFM) -+ berssem
hay (BH) supplemented with 10% molasses ad lib. Ration (9): 70% of TON requiremenl from CFM + spent wheat straw (SWS)
supplemented with 10% molasses ad lib, Ration (C): 60% of TON requirement from CFM + SWS supplemented with 10%
molasses ad lib. Ration (0): 50% of TON requirement from CFM + SWS supplemented with 10%
molasses ad lib. The main results could be summarized as follows : 1- The OM intake, digestibilities of most nutrients and nutritive values were
decreased with increasing SWS proportion in the rations during gestation and
suckling periods. 2· Rations (A). (8) and (e) and rations (Al and (8) were covered the nutritional
requirements of ewes during gestation and suckling periods, respectively. 3- Rations (A) and (9) recorded the best values of milk as quantity and quality
during suckling period. 4- Improved weaning weight end daily gain were recorded (or lambs bom from ewes
red rations (A) and (8) during suckling period. ~ Using SWS in sheep nutritioo decreased feed cost. Keywords: pregnant ewes. suckling lambs, milk production, spenl wheat straw