Abstract
These studies were conducted to determine the effect of source of “crude fiber” on its digestibility and degree of utilization by swine and to investigate the advantages of substituting analyses for cellulose and lignin in place of the usual crude fiber estimation. Ruffex, wheat straw pulp, alfalfa meal, and oat hulls, were added to a good basal ration in amounts to give equivalent cellulose values. Determinations of digestibility and metabolizable energy were made, using Duroc Jersey and Poland China barrows weighing initially 125 pounds. Digestibility of cellulose in rations containing about 50 percent of their cellulose from woodflock, Ruffex, or wheat straw pulp averaged 41, 46, and 68 percent, respectively. The added cellulose in the same series was apparently digested to the extent of 21, 30, and 92 percent, respectively. Comparisons of varied fiber sources with woodflock showed the following decreasing order of cellulose digestibility: alfalfa meal, woodflock, wheat straw, and oat hulls. The differences cited above may be associated with lignification of the cellulose and/or chemical variation in the cellulose itself. Cellulose and crude fiber digestibilities exhibited similar trends, but the former exceeded the latter. Crude fiber content of the rations averaged 84 percent of the cellulose and 72 percent of the cellulose plus lignin contents. A modified lignin analysis was developed which gives an average lignin digestibility of 5.1 percent. Metabolizable energy values, expressed as a percent of the digestible energy, show that the organic acids produced in the digestion of cellulose are highly utilizable by the animal. Copyright © . .