Effect of Various Carbohydrate Additives on Silage Quality of Bio-Digester Slurry-Irrigated Pennisetum purpureum

The objective of this study was to determine the effect of carbohydrate additives on the silage quality of Napier (Pennisetum purpureum) fodder harvested from fields irrigated with and without cattle bio-digester slurry (BDS). The already established Napier fodder was harvested manually at about 15 cm above the ground and the height of the grass ranged between 1.2 to 1.5 meters tall. Three carbohydrate additives namely, molasses, brown sugar, maize meal were added during the silage making at 10% level along with a control, and each treatment was replicated four times. Approximately 600 g of the chopped grass materials were mixed thoroughly with the additives and ensiled in bottle jars and stored for six weeks at room temperature. The physical properties of the ensiled Napier fodder did not differ significantly (P>0.05) among the treatments. There were no significant differences observed for NH3 and NSC of the silages (both BDS and no BDS) after ensiling the Napier grass for 42 days. The DM, CP, NDF, ADF and ash contents did not differ. All silages were slightly moist with maize additive (without BDS) scoring the highest. The colour of silage is of good quality, since the pH of these silages show that there was adequate fermentation except that of the control which was with a pH of 6.2. All the silages had low pH values (3.5–4.5) except for the control which had a pH of 6.2, reflecting lower quality silage. The minerals concentrations of the silages were not significantly different except for Mn which was significantly (P<0.05) higher in maize treated silage compared with the rest of the silages. It is concluded that application of carbohydrate additives during ensiling of Napier fodder has positive results. However BDS Napier grass did not differ with no BDS on the quality of the silage in all the additives. The additives (molasses, sugar and maize) were added at 10% of the total weight of the chopped material and showed a positive effect in the fermentation quality of silage.