This project was planned to study the influence of varying levels of urea and molasses on chemical composition of wheat straw (WS) fermented with cattle manure (CM) for different time periods and to examine the effect of fermented WS (FWS) on nutrient intake, digestibility, ruminal characteristics, in situ digestion kinetics, nitrogen (N) utilization, milk yield and its composition in Nili-Ravi buffaloes.
The laboratory experiment was conducted to examine the influence of varying levels of urea and molasses on chemical composition of WS fermented with CM for different time periods. Cattle manure was mixed completely with ground WS in a ratio of 30 to 70 on dry matter (DM) basis and this material was treated with different levels of urea (0, 2 and 4%) and molasses (2 and 4%). Four silos for each treatment were prepared. The material in these silos was allowed to ferment for 20,30 and 40 days in incubator at 40C.
Dry matter contents of WS were decreased (P<0.05) with increasing fermentation time, however they increased with increasing level of urea. Dry matter contents of FWS were not affected by molasses levels. Wheat straw treated with 4% urea, 2% molasses and 20 days fermentation time yielded higher DM (65.98%) compared with all other treatments. The pH of FWS was increased (P<0.05) with urea level; however it was not affected (P<0.05) by molasses levels. The pH of FWS was also affected with fermentation time. Crude protein (CP) contents of FWS were significantly increased (P<0.05) with increasing fermentation time, urea and molasses levels. The percent improvement in CP was 35.73% from 20 days to 40 days of fermentation, whereas, the improvement in CP was 65.79% between 2 and 4% urea levels. The urea X fermentation time; urea X molasses; and urea molasses X fermentation time significantly affected (P<0.05) CP contents of FWS, whereas, it remained unaffected by molasses X fermentation time interaction.
The ammonia-N (NH3-N) and true protein (TP) contents of FWS were increased (P<0.05) with increasing urea level, molasses level and fermentation time. The neutral detergent fiber (NDF) contents of FWS were significantly reduced with increasing time from 20 to 30 days, however, non-significant difference (P<0.05) in NDF contents of FWS was observed when it was ensiled for 30 and 40 days. The acid detergent fiber (ADF) contents FWS were affected (P<0.05) by fermentation time, utea and molasses levels. In conclusion, 4% urea and 4% molasses treated WS fermented with CM for 40 days improved the protein fractions and reduced the fiber fractions.
Metabolic and in situ digestion kinetics studies were conducted to evaluate the dietary effects of different levels of FWS on nutrient intake and digestibility, ruminal characteristics in situ digestion kinetics, and N-metabolism in ruminally cannulated Nili-Ravi buffalo bulls fed restricted diets. The 4% urea and 4% molasses treated WS was fermented with CM in the ratio of 70 to 30 for 40 days in the cemented pit. Four Nili-Ravi buffalo bulls weighing 350 + 30 kg, fitted with ruminal cannulae were used to evaluate the effects of FWS in a 4X4 Latin Square Design. Four iso-nitrogenous and sio-caloric rations having 0 (FWSO), 10 (FWS10), 20 (FWS20) and 30% (FWS30) FWS in the placed of concentrate were formulated and were fed to bulls at 1% DM of their bodyweight daily (in two frequencies).
Ruminal Dm and NDF degradabilities, rate of disappearance and extent of digestion were significantly (P<0.05) higher in buffalo bulls with 100% FWS compared with other treatments. Ruminal DM and NDF degradabilitys, rate of disappearance and extent of digestion were significantly higher with 75 and 50% FWS compared with 100% WS. The ruminal Dm and NDF lag time bulls was reduced (P<0.05) with increasing level of FWS. Dry matter, organic matter (OM), CP, NDF and ADF intakes were similar (P<0.05) in buffalo bulls fed varying levels of FWS. Dry matter, OM NDF apparent digestibilities were significantly different in buffalo bulls fed varying levels of FWS. However, the apparent CP digestibility was not affected (P<0.05) by the levels of FWS in buffalo bulls.
Nitrogen intake, N-outgo, N-balance, N-balance percent of digestible N-intake and BUN did not differ (P<0.05) in buffalo bulls fed varying levels of FWS. Replacement of 30% FWS with concentrate in the buffalo bulls diet had higher DM, OM and NDF digestibilities. The FWS had higher ruminal Dm and NDF rate and extent of digestion. The N-balance was positive in buffalo bulls fed diets containing varying levels of FWS.
The performance study was conducted to evaluate the influence of varying substitution levels of FWS with concentrates on nutrients intake and digestibility, milk yield and its composition in Nili-Ravi buffaloes. The 4% urea and 4% molasses treated WS was fermented with CM in the ratio of 70 to 30 for 40 days in the cemented pit. Four iso-nitrogenous and iso-caloric rations having 0 (FWS0), 10 (FWS10),20 (FWS20) and 30% (FWS30) FWS in the place of concentrate were formulated and were fed lactating buffaloes at ad libitum.
The OM, DM, CP, NDF and ADF intake remained unlatered (P<0.05) in lactating buffaloes fed diets containing varying levels of FWS. The NDF and ADF digestibilities in lactating buffaloes were significantly higher (P<0.05) with FWS20 and FWS30 diets when compared with FWS10 and FWS0 diets. However, the non-significant (P<0.05) differences in apparent DM, OM and CP digestibilities have observed in lactating buffaloes fed different DM, OM and CP digestibilities have been observed in lactating buffaloes fed different levels of FWS.
Milk yield (4%FCM) in buffaloes fed diets containing different levels of FWS was similar. The percent milk fat, CP, total solids and solids not fat and their yield were non-significant (P<0.05) in buffaloes fed varying amounts FWS. The BUN and MUN in Nili-Ravi buffaloes fed diets containing varying levels of FWS were similar.
From this study, it can be concluded that urea plus molasses treated WS fermented with CM did not affect the nutrient intake, digestibility, BUN MUN, milk yield and its composition when substituted for concentrate up to 30% DM in lactating buffalo ration. However, extensive feeding trials involving more number of buffaloes are warranted before any practical recommendation.