This study was conducted in Nutrition Lab. to investigate the effect of the type and level of substitution of urea with ruminant manure, M (sheep, cow and buffalo) on basis of nitrogen (N) content on the nutritive value of rice straw silage (RSS). Accordingly silages were nominated as, S-RSS, C-RSS and B-RSS. Urea (U) was substituted with dried manure at 6 combinations, 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50 of U:M. Silage samples were prepared by treating chopped straw with pre-treated solution contained 10% low quality debis and 2% urea. Results showed that lower (P˂0.01) DM loss (11.4%) was observed in S-RSS, and with addition of urea only (3.6%).
Samples of S-RSS and C-RSS recorded higher (P˂0.01) Fleig points (Fp) as compared with those prepared by the addition of B-RSS, 60.42, 55.58 and 49.59 respectively. Reduction (P˂0.01) in this parameter was noticed in samples prepared with a combination of 100:0. Aerobic stability (AS) was a reduced (P˂0.01) in samples prepared by addition of S-RSS by 15 and 13 hours in comparison with samples of C-RSS and B-RSS respectively. Samples prepared with combination of 100:0 were prior (P˂0.01) as compared with other samples.
Results also showed an increase (P˂0.01) in in vitro digestibility of organic matter (IVOMD) in samples of S-RSS in comparison with samples prepared by addition of C-RSS and B-RSS, 49.99, 44.59 and 42.77% respectively. Samples prepared with combination of 100:0 recorded lower (P˂0.05) in vitro digestibility of dry matter (IVDMD) as compared with combinations of 70:30 and 60:40 of U: M, 40.52, 45.36 and 45.94% respectively.