DIGESTIBILITY AND VOLUNTARY INTAKE BY WETHERS OF DIETS CONTAINING AMMONIATED OR HIGH-PRESSURE STEAM-TREATED NEEPAWA WHEAT STRAW FROM FIELDS FERTILIZED WITH MANURE OR CHEMICAL FERTILIZER

High-pressure steam treatment and ammoniation were compared as procedures to improve the intake and digestibility of Neepawa wheat straw by wethers. In addition, the effects of hog manure or commercial fertilizer upon the nutritional value of Neepawa wheat straw were examined. Ammoniation increased the availability of energy and N of diets containing straw from both fertilizer treatments. Straw from the manured field was of slightly higher quality before and after ammoniation than was straw from the chemically fertilized field. High-pressure steam treatment increased the digestibility of energy-yielding components of diets containing chemically fertilized straw more than ammoniation, and increased intake of digestibile energy to levels significantly greater than those of untreated or ammoniated straw. In vitro forage evaluation consistently underestimated the nutrititive value of rations containing high levels of either untreated or processed straw.