Mineral Influences upon Urea Utilization and Cellulose Digestion by Rumen Microorganisms Using the Artificial Rumen Technique

Six in vitro fermentation series with rumen microorganisms were employed in studying the influence of minerals upon urea utilization and cellulose digestion. In the first series, five levels of water extracts from immature clover hay, rumen ingesta, and manure were evaluated. Determination of two active fractions, namely the sugar and the ash, in blackstrap cane molasses were made in the second series. The third fermentation series measured the effectiveness of different levels of molasses-ash upon rumen microorganisms in the absence and in the presence of two levels of starch, using a constant amount of cellulose. The ashes of molasses, immature clover hay, and mature timothy hay were found approximately comparable on a weight basis in stimulating fermentations in the fourth series. In the fifth and sixth series, specific mineral elements were studied alone and in the presence of molasses-ash. Phosphorus and iron were found effective in stimulating urea utilization and cellulose digestion by rumen microorganisms. Evidence was presented that other elements besides iron and phosphorus were involved in rumen bacterial physiology in addition to sodium, potassium, calcium, magnesium, chlorine, and sulphur which were routinely used in artificial saliva.