Further Experiments with Sodium Bisulfite as a Preservative for Grass Silage

Abstract

Results of Experiment 1 were as follows: Prebloom alfalfa, ensiled wilted or unwilted without preservative, produced poor quality silage with large losses of digestible nutrients. The same crop ensiled unwilted with 8 lb. sodium metabisulfite per ton produced silage of excellent color, odor and feeding value, with greatly increased retention of digestible nutrients. One-tenth bloom alfalfa was equally well preserved, from the standpoint of nutrient loss, when ensiled wilted or treated with metabisulfite. The bisulfite treated silage, however, was superior in color and odor, and analysis indicated a more desirable type of fermentation. The untreated, unwilted silage made from this crop was inferior with respect to both quality and nutrient losses. Addition of both bisulfite and either dried beet pulp or ground corn cobs to this early bloom alfalfa reduced nutrient losses from the silo, and increased the feeding value of the silage. Full-bloom alfalfa was considerably lower in feeding value than the two earlier cuttings, and when ensiled unwilted showed little benefit from the use of bisulfite over no preservative. Top spoilage was excessive in the wilted silage made from this crop. The results of Experiment 2 were as follows: First cutting alfalfa ensiled in five 5' × 20' wood stave silos was treated with 0, 5, 8, 12, and 18 lb. of sodium metabisulfite per ton of fresh forage. All treated silages were superior to the untreated silage with respect to color, odor, and retention of digestible nutrients; however no improvement was noted as the rate of application was increased above 5 lb. per ton, and palatability was impaired slightly at the 18 lb. per ton level.