[Treatment of wheat straw with urea, calcium hydroxide or ammonium sulfate].

An experiment was conducted to evaluate the effectiveness of urea, ammonia sulphate or calcium hydroxide, in improving the nutritive value of wheat straw for ruminant feeding. Wheat straw was treated with each of three solutions (w/w) containing: 5% urea - 50% H2O (5U); 2% urea - 2% CaOH - 50% H2O (2U), or 5% ammonia sulphate - 2% CaOH - 50% H2O (5S). The treated straw was then ensiled in triplicate in sealed polyethylene bags for 30 days at ambient temperature (15-22 degrees C), except for the untreated straw, which was used as control (T). All treatments were then subjected to the following determinations: pH, moisture, crude protein, ammonia N, ashes, cellular walls, hemicellulose, cellulose, lignin, silica, gross energy, and dry matter in vitro digestibility. The pH value of the 5U treatment was higher (p less than 0.01) than that of 2U and 5S, and the moisture percentage increased in all treated straws, as compared to the control. Both crude protein and ammonia N contents were higher in the 5U treated straws (14.66; 0.6%), 2U (6.41; 75%), 5S (9.54; 94%) in comparison with T (2.63; 50%). The ash percentage increased significantly in 2U and 5S (p less than 0.01) in relation to T and 5U, and the cellular wall content decreased in the 5U, 2U and 5S treated straws, as did cellulose. Gross energy values were higher in the treated straws, and the dry matter per cent digestibility was also higher, although not in a significant degree (p less then 0.01) in the 5% urea-treated straw (45.03) than in 2U (42.43), 5S (34.82), and T (42.36).(ABSTRACT TRUNCATED AT 250 WORDS)