Evaluation of silages of hybrids of napier grass and sorghum in the low country wet zone of Sri Lanka

Silages of hybrids of napier grass (CO-3 or CO-4) and sorghum and their combinations (50% napier grass hybrid + 50% of sorghum) were tested under three cutting intervals (4, 6 and 8 weeks). Sorghum silage had a leafy and soft texture with a fruity smell, which proved its desirable character with normal lactic acid fermentation. As such, it was with its comparatively higher dry matter content at the 6 or 8 weeks cutting interval, more suitable for ensiling. The crude protein concentration was not modified by the ensiling process, which was proved by the low ammoniacal nitrogen content. Sorghum silage had lower pH values at all three cutting intervals. On the basis of the NH₃-N/TN content (<10%), all silages could be considered as of good quality. Sorghum silage could be considered as the best among tested silages as compared with hybrid napier var. CO-3 or CO-4. The optimum quality of the sorghum silage with the highest soluble carbohydrates concentration and lactic acid >3% could be obtained at the 6-week cutting interval.