Chemically Degraded Wood in Finishing Beef Cattle Rations

Abstract

Three criteria were used to examine the energy value of sulfite processed Douglas fir in finishing beef cattle rations. The first of these was a 126-day performance trial utilizing 12 Hereford steers allotted to two treatments: (1) 78% barley ration, and (2) 70% wood ration. There was no significant difference (P > .05) in average daily gain between the two groups, but control animals did gain 0.48 kg per day faster than 70% wood-fed steers. The relatively low dry matter intake of the 70% wood-fed group was attributed to the high moisture content (68%) and reduced digestibility of the ration. Volatile fatty acid concentrations present in the rumen of either a 78% barley ration or a 70% wood ration were determined in the second phase of the experiment. The 70% wood ration resulted in the formation of a larger proportion of acetate and a lower percentage of propionate than the barley ration. The proportion of acetate, propionate and butyrate formed on each ration was used to calculate an energetic efficiency for the conversion of hexose energy to VFA energy in the rumen. Calculations revealed that hexose energy in the 70% wood ration was converted to VFA energy with 9% less efficiency than hexose energy of the barley diet. Dry matter, acid-detergent fiber (ADF), and gross energy digestibilities of the 70% wood ration were determined in three steers by the chromic oxide method. The mean digestibility values calculated by this technique for dry matter, acid-detergent fiber, and groos energy were 55.71, 62.87, and 54.38%. respectively. Copyright © 1973. American Society of Animal Science. Copyright 1973 by American Society of Animal Science.