Nutrient Losses, Quality, and Feeding Values of Wilted and Direct-cut Orchardgrass Stored in Bunker and Tower Silos

Abstract

Summary First-cutting orchardgrass was preserved as: 1. Wilted silage stored in a tower silo. 2. Direct-cut, sodium metabisulfite–treated silage, stored in a tower silo. 3. Direct-cut sodium metabisulfite–treated silage, stored in a bunker silo. These silages were prepared in each of two successive years and all silages were sealed with weighted plastic covers. The silages were compared on the basis of storage losses, storage temperatures, chemical quality, feeding trials, and digestion trials. An expression of silage feeding value which combines dry matter intake rate and TDN content has been proposed. Tower storage of wilted forage and bunker storage of the direct-cut forage were about equally efficient in preserving feed nutrients. Tower storage of direct-cut forage was consistently less efficient, primarily because of higher seepage losses. All silages were of good chemical quality and of about equally high feeding value. The wilted silage, however, contained more butyric acid in both years and was consumed by dairy cattle in significantly greater amounts one year. The bunker silo, as used in this experiment, was a more suitable storage structure for direct-cut orchardgrass than a tower silo. However, when forages were stored in tower silos, the wilting method was generally more satisfactory than direct-cutting combined with sodium metabisulfite treatment.