This study was carried out to investigate the possibility of utilizing the
processed rice straw as an animal feed ingredient. Sixteen growing male Barki lambs
were divided into four similar groups. The groups were assigned at random to receive
one of the four experimental rations. All four rations consisted of a concentrate
mixture in a mash form (50%). and roughage - urea mixture (50%). The roughage -
urea mixture was made of rice straw (76%), wheat bran (12%) , molasses (10%) and
urea (2%). Treatments represented different forms of the roughage -urea mixture. It
was offered mixed with no treatment (R1) , ensiled (R2) or made into a feed blocks
(R3). In the fourth treatment (R4) both the concentrate and the roughage portions
were mixed and blocked. The feeding experiment followed by metabolism trial was
lasted for days along with studying fermentation in the rumen and some blood
metabolites. Results showed that ration R4 resulted in higher OM intake and rate of OM
and CP digestibilities. Animals fed R2 and R4 had the highest values of nitrogen
retention. Growing sheep fed R4 had higher values of digested nutrient Intakes
expressed as TON Intake g/Kg BW (19.6) and OCP intake g/l(g BW (2.90). Animals fed R4 (Blocked) had the highest values of average daily gain (76
g/d) followed by those fed R2 (62 gld) (ensiled), while R3 resulted In the lowest AOG
varues (44 g/d). Processing of rice straw with concentrate feed mixture as feed blocks
improved the performance of growing sheep.