Effect of nitrogen fertilization and stage of maturity of mottgrass (Pennisetum purpureum) on its chemical composition, dry matter intake, ruminal characteristics and digestibility in buffalo bulls

Four ruminally cannulated buffalo bulls were fed mottgrass diets using a 4 x 4 Latin square design. Treatments were arranged factorially and consisted of mottgrass fertilized with 0 for 46 Kg nitrogen (N) per acre and harvested at 40 and 60 days of age. Nitrogen fertilization improved the concentrations of neutral detergent fiber (NDF), and acid detergent fiber (ADF) in early-cut mottgrass (ECM) but, the acid detergent lignin (ADL) contents were higher in the late-cut mottgrass (LCM). The crude protein (CP) contents of the mottgrass decreased with advancing maturity, but N fertilization increased CP at both maturities. The intake of dry matter (DM), organic matter (OM), CP, NDF and ADF were higher by buffalo bulls fed ECM than those fed LCM. The ruminal pH increased in first 6 hours post feeding in animals fed N fertilized mottgrass and may be due to higher concentration of ruminal ammonia. The digestibilities of DM, OM, CP, NDF and ADF were higher by buffalo bulls fed ECM than those fed LCM. However, the application of N fertilizer did not affect the digestibilities of these nutrients.