Cotton seed hulls (CSH) ground through 5,8 and 12mm sieves, were tested for physical characteristics and were incorporated in three complete diets as sole source of roughage (50%) and compared with a conventional ration in order to assess the effect of particle she on nutrient utilization by feeding to 24 Nellore rams (26-35 kg) using a completely randomized design in metabolism experiment. Bulk density, molasses absorbability decreased and particle size increased as the sieve size increased from 5 to 12 mm. DM intake was significantly (P<0.01) higher on complete diets compared to conventional ration. Digestibilities of all the nutrients except CP were comparable on all the experimental rations. CP digestibility was significantly lower (P<0.01) on diet 1 compared to other test diets. All the experimental animals were on positive N, Ca and P balances. The results of this study indicate that CSH could be utilized as roughage source in complete diets for sheep and that grinding with 12 mm sieve which yielded an average particle size of 1740 µ. was optimum.
