Lime treatment of agricultural residues to improve rumen digestibility

Bagasse, bajra (african millet, Pennisetum typhoideum), jowar (indian millet, Sorghum vulgare) and tobacco stalks were treated with lime to increase the rate and extent of dry matter digestibility. All four materials were treated with 10 g Ca(OH)2/100 g dry biomass at 100°C for 1 to 2 h. The residual calcium in the biomass after lime treatment and washing was 1.5 to 2.7 g/100 g dry lime-treated biomass. Samples of each biomass were placed in fine-mesh nylon bags which, in turn, were placed in the rumen of a cannulated steer. The bags were removed at periodic intervals and analyzed for dry matter digestibility, neutral detergent fiber, and acid detergent fiber. After lime treatment and addition of water-extracted solubles, the 48-h dry matter digestibilities were: bagasse, 62.7% treated vs. 30.8% untreated; bajra, 89.9% treated vs. 45.1% untreated; jowar, 82.9% treated vs. 54.1% untreated; and tobacco stalks, 67.9% treated vs. 34.4% untreated. In each case, lime treatment approximately doubled the digestibility making it an effective method to upgrade the rumen digestibility of agricultural residues.