Effect of different urea treatment methods on urea degradation and nutritive value of cenchrus (Cenchrus ciliaris) straw

Four different urea treatment (urea 4 kg/100 kg straw) methods were adopted to improve the quality of cenchrus straw. These treatments included i) conventional (T1), ii) layering of urea treated straw and untreated straw in alternate layers (T2), iii) pouring concentrated urea solution into polyethylene bags (T3) and iv) putting straw soaked with concentrated urea solution in the middle of the bags (T4). An additional treatment (T5), was done in alternate layers similar to that of T2, but the concentration of urea in total straw was kept 2 per cent W/W. After 21 days of incubation, the bags were opened and contents of each bag in T2, T3, T4 and T5 was divided into two parts. One portion was mixed thoroughly while another portion was divided into wet and dry parts. The pH, per cent total N, ammonia N and urea N in T1, T2, T3, T4 and T5 were 8.90, 2.73, 1.32 and 0.42; 9.0, 2.52, 0.80 and 0.47; 8.0, 2.59, 0.16 and 1.66; 8.4, 3.05, 0.23 and 2.06 and 9.0, 2.04, 0.84 and 0.15, respectively. In the present experiment about 65 to 85 per cent urea was hydrolyzed in conventional method (T1) and in layer methods (T2 and T5), whereas in treatments where concentrated urea solution was either poured (T3) or placed in the form of lump (T4) inside the straw, the urea could not be hydrolyzed to a great extent. The concentration of different fibre fractions (ADF, NDF, cellulose, hemicellulose and lignin) in straw remained unchanged due to treatment. However, the IVDMD was higher (P<0.05) in T1 and T2 than those observed in T3, T4 and T5.