Chemical Treatment of Wheat Straw

An in vitro digestion study, a lamb growth trial and a lamb digestion trial were conducted to evaluate the effect of different NaOH and Ca(OH)2 treatments on the energy availability of wheat straw. In vitro dry matter disappearance (IVDMD) of wheat straw was increased 29% by chemical treatment with 1% NaOH plus 3% Ca(OH)2 and by as much as 86% by a 4% NaOH plus 1% Ca(OH)2 treatment. A significant amount of hemicellulose was solubilized by chemical treatment with NaOH and Ca(OH)2, but little cellulose was solubilized. Rate and extent of both hemicellulose and cellulose digestion of treated wheat straw were increased significantly in comparison to corresponding measures for untreated wheat straw. Lambs fed chemically-treated wheat straw gained significantly faster and more efficiently and consumed more dry matter per day than those fed untreated wheat straw diets. Chemical treatment of wheat straw significantly increased dry matter, organic matter cellulose and hemicellulose digestibilities in the lamb digestion trial. Organic matter digestibility was increased from 51.3% for untreated wheat straw to 65.3% for 4% NaOH-treated wheat straw.