The Chemical Composition and Loss of Nutrients in Silage Made With the Addition of Sodium Metabisulphite and Halogenated Acetate of Glycol

Abstract

Several products have recently been introduced as additives in silage-making which may bring about a partial sterilization of the mass. These include sodium metabisulphite and Sovilon (halogenated acetate of glycol). The former substance has been used to some extent in America and results from experiments there indicate that when it is added at approximately 8 lb. per ton of herbage a good quality silage is produced. Several workers (1,2) have shown that when metabisulphite is used the volatile acid and volatile base content of the silage is low, but that appreciable amounts of lactic acid are formed. The conclusions drawn are that metabisulphite inhibits protein breakdown and butyric acid production, while allowing a lactic acid fermentation to take place. On the other hand, BATEMAN et al. (3) suggest that the shift of micro-organisms in a metabisulphite silage from a dominantly proteolytic to a dominantly lactic acid forming population was slower than in untreated silage or in silage to which molassed beet pulp had been added. Because of the lower bacterial activity in metabisulphite silage, it is claimed that the loss of nutrients is lowered, and COWAN et al. (4) and GORDON et al. (9) have shown that losses of dry matter, crude protein and nitrogen-free extract are much lower than those in untreated or molassed silage. Using high dry matter herbage, however, GORDON and his co-workers (5) found no difference in dry matter losses, but loss of sugar was substantially lower in the metabisulphite silage. There is also some indication that total digestible nutrients is silages made with metabisulphite were higher than that in untreated silages (4).Little precise information is available on the effect of adding Sovilon, apart from one set of results which show a lower volatile acid 16 content in grass slurries after 28 days when this additive had been used, compared with a slurry with no addition (6).

Nutrient Preservation and Acceptability of Forages Ensiled With Sodium Metabisulphite at Varying Levels of Compaction and Dry Matter

“…Murdoch et a:1. (8), in separate tests of various amounts of chopped and unchopped forages, from 400 pounds to 13 tons, tested bisulphire idditions of 0 to 16 potnds per ton. Hd concluded that bisulphite low6red the loss of nutrients and produced a better quality of silage.…”

Partial Wilting of Grass Crops for Silage

“…In Britain the deliberate wilting of crops for silage is not frequently practised and it is only in recent years that wilted silages have been properly examined; mainly by Murdoch and his co-workers at the National Institute for Research in Dairying, Reading (4,17,18,20,19).…”