IMPACT OF VARYING MOISTURE LEVELS, DIFFERENT ADDITIVES AND FERMENTATION PERIODS ON NUTRITIVE VALUE OF LEGUMINOUS AND NON-LEGUMINOUS FODDER SILAGES IN LACTATING NILI RAVI BUFFALOES

Efficient ruminant productivity is only possible if a steady supply of quality forage in sufficient amounts is made available to them. In Pakistan, there are two important fodder scarcity periods, one is during winter months (November to January) and other is during summer months (May to July) and in rest of the year fodder availability is fairly regular and abundant. This abundant fodder if not properly managed is the wastage of fodder resource. This situation calls for the exploration of different means to improve quality and quantity of roughages without sacrificing the area under cash crops. Manipulating this surplus fodder can bridge the gap between supply and demand. Silage making is one of the important techniques in this regard (Tauqir et aI., 2007). The main goal of silage making is to preserve as much of the nutritional value of the original crop as possible. Preservation is achieved by acidity and by maintaining an oxygen-free (anaerobic) environment. Acids are produced by bacteria that convert fermentable carbohydrates into organic acids, predominantly lactic and acetic acids. As fermentation progresses, more acids are produced, pH drops, and eventually the acidity level is adequate to inhibit or kill most bacteria and other microorganisms. At this pH if protected from exposure to air and water seepage, silage can be preserved for a long period. Concentrations of fermentable carbohydrates in the forage, its buffering capacity, dry matter (OM) content and the number and type of bacteria present on the forage are the main factors that could affect the rate of pH decline and final pH of the silage (Boisen et al., 1996; Higginbotham, et al., 1998). Grasses have relatively low buffering capacity and low concentrations of fermentable carbohydrates, therefore, pH decline is not rapid and final pH is usually high. Leguminous fodders on the other hand, have a high buffering capacity (due to high protein and mineral content), and relatively high concentrations of fermentable carbohydrates, therefore, pH drop in leguminous crop silages was also slow and loss of nutrients could be high (Boisen et al., 1996). Leguminous crops that are extensively wilted prior to ensiling to lower the moisture content undergo very limited fermentation and final pH values are usually between 4.5 and 5, which are higher than that of nonleguminous silages. Therefore, for a rapid and extensive fermentation to occur, the forage must have high concentration of fermentable carbohydrates, low buffering capacity, relatively low dry matter content (2040%), and adequate lactic acid bacteria present prior to ensiling. Any fodder, which has sufficient amount of fermentable carbohydrates, can be ensiled, but the most popular fodder is maize (Woolford, 1984). However, jambo and mott grasses, lucerne and berseem (legumes fodders) can be used for silage making provided that a source of fermentable carbohydrates is added before ensilation (Tauqir N. A. 2007). The choice of crops for ensilage depends primarily on the local environment. Generally high yielding multicut fodders can be a good choice for silage making. Various silage additives like molasses, starch, nitrogen (N), bacterial inoculants and different types of absorbents are available and are used for different reasons. Additives are used to improve nutrient composition of silage to reduce storage losses by promoting rapid fermentation, to reduce fermentation losses by limiting the extent of fermentation and to improve bunk life of the silage (increase aerobic stability). Various additives like molasses (Boisen, et al., 1996) and crushed grains (De Visser, et aI., 1998) are added in non-leguminous fodders as a source of soluble carbohydrates before ensilation to increase the lag phase in silage. While, leguminous fodders are already high in crude protein (CP) and moisture content. So, before ensiling the leguminous fodders, the moisture content is reduced either by field wilting or by the addition of some absorbent (Fransen and Strubi, 1998). Dry roughages high in OM and low in N like wheat straw can be used to improve the OM of berseem and lucerne before ensilation (Tauqir N. A. 2007). However, the scientific evidence regarding the nutritive value of silages of grasses and legumes as affected by the use of various additives, fermentation periods and moisture absorbents is limited and