Two experiments were conducted to evaluate effects of barley grains particle size on ruminal pH and ammonia concentration of rams (experiment 1) and carcass characteristics (experiment 2) of male lambs fed high urea diet. Treatments in two experiments were (1: basal diet + whole barley grains, 2: basal diet + ground barley grains with a 5 mm screen, 3: basal diet + ground barley grains with a 3 mm screen and 4: basal diet + ground barley grains with a 1 mm screen). Basal diet (on a dry matter (DM) basis) consisted of 365 g/kg corn silage, 10 g/kg limestone, 10 g/kg urea, 5 g/kg salt, 10 g/kg a vitamin-mineral premix and 600 g/kg of barley. In experiment 1, three 2-year old rams were fistulated for measuring ruminal pH and ruminal ammonia concentration. Ruminl pH was decreased by feeding ground barley grains through a 1 mm screen compared to feeding the whole barley grains (P<0.05). However, Ruminal ammonia concentrations were similar for all groups. In experiment 2, twenty four male lambs were used in a completely randomized design. Lambs were fed with the above mentioned diets for 90 days. Average daily gain, feed conversion ratio, average DM intake was significantly affected by treatments (P<0.05). Final body weight, cold carcass weight, dressing percentage, back fat thicknesses, carcass cuts (leg, shoulder, back and neck weights), internal organs (kidney, lungs, heart and gastrointestinal tract) weights were not significantly different between diets (P>0.05). Lambs fed diet containing ground barley with 3 mm of screen had (P<0.05) higher longissimus muscle area compared to lambs fed whole barley grain. Consumption of whole barley grains increased DM intake and pelvic and abdominal fats. As a conclusion, the consumption of ground barley grain with a 3 mm or a 5 mm screen is suggested for feeding lambs fed high urea diet. Manuscript profile

This study was conducted in two separate experiments. Four rumen-cannulated sheep were allocated in the first experiment to evaluate date by-product (DBP) and date seed (DS) nutrients degradation in rumen. In experiment two eighteen fattening lambs were allocated in three different treatments (6 animals/treatment) to evaluate DBP effects on animal performance and nutrients’ digestibility. Three experimental treatments were as follow; 1) control group (C, diet without DBP inclusion), 2 and 3) diets with DBP at two inclusion levels of 10(DBP10) and 20(DBP20) %, respectively. The performance trial lasted 90 days. The results of degradation kinetics showed that both wash out fraction (a) and potentially degradable fraction (b) were greater in DBP compared to DS for dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) degradation. Effective degradability for DM, OM and NDF was differed between DBP and DS in all measured passage rate times. Results of the performance trail revealed that inclusion of 20% DBP decreased daily gain (DG) and hence increased feed conversion ratio (FCR; 7.1, 7.7 and 8.6 for C, DBP10 and DBP20, respectively). Daily gain was 210, 200 and 160 g/d for C, DBP10 and DBP20; respectively showing that inclusion of 20% decreased gain but the inclusion of 10% had an acceptable gain compared to control treatment. The diet cost was decreased by inclusion of DBP. Considering the degradation rate of DBP in rumen and also the performance trial results, it could be suggested that limited inclusion of DBP in sheep diet could decrease dietary costs and improve economic efficiency without reducing gain or efficiency in intensive lamb fattening system. Manuscript profile