Preservation and Feeding Value of Alfalfa Stored as Hay, Haylage, and Direct-Cut Silage

Abstract

Summary The preservation efficiency and chemical quality of silages made from direct-cut and heavily wilted (haylage) alfalfa were compared in three successive years. Silages were stored in gas-tight steel silos. A minimum of 4% loss of stored dry matter was observed under the haylage system. This was attained by maintenance of the gas-tight condition and provision of a cap of unwilted forage. Very poor preservation of haylage dry matter was obtained when both of these precautions were neglected. Storage losses of high-moisture direct-cut silage were 22-24% of the stored dry matter, although spoilage was a minor problem. Major improvement of silage chemical quality by extended wilting was indicated by statistically significant negative correlations between dry matter content of the stored forage and ammoniacal nitrogen, acetic acid, propionic acid, and total acid. The positive correlation of lactic acid and dry matter was small and not significant and pH was rather constant over the entire range of 20-53% dry matter. High chemical quality of haylage was indicated by low levels of undesirable constituents, although pH was generally high and only small amounts of lactic acid developed. The feeding value and digestibility of the silages was compared to barn-dried hay made from the same crops. Animal acceptance, milk production, and live weight gains showed barn-dried hay to have, generally, the highest feeding value and direct-cut silage the lowest. Haylage surpassed high-moisture direct-cut silage in these respects with the exception of milk production, which was about equal on the two types of silage. Dry matter consumption was positively correlated with dry matter content of the silage. High negative correlations were found between silage dry matter consumption and content of volatile organic acids and ammoniacal nitrogen. Lactic acid content and pH showed poor correlations with dry matter consumption. Digestibility coefficients were generally highest for barn-dried hay, lowest for haylage, and intermediate for direct-cut silage.