Nutritional quality of large round bale silage as affected by compaction, color of wrap, or preservative in Southcentral Alaska

Abstract

Large round bale silage (LRBS), fermented hay, baled at 45-65% moisture content might be a better product than air-dried hay for farmers and ranchers in Southcentral Alaska. Variable weather and sometimes unfavorable conditions for drying hay to the required 18% moisture content makes high quality hay production unpredictable. Our study was designed to determine what practices might produce the highest nutritional quality LRBS. Treatments included using black and white plastic bale wrap, two different baler compaction levels, and application of a buffered propionic acid preservative. The study used four different forage fields over a two year period. Three fields were harvested on each cutting date. We measured dry matter (DM), neutral detergent fiber, acid detergent fiber, lignin, acid detergent insoluble nitrogen, crude protein, and digestible energy. Fermentation analysis measured levels of lactic, acetic, propionic and butyric acids, ammonia and pH on LRBS. The denser bales, bales wrapped in black plastic, and those treated with preservative produced highest quality forage. Dense bales had lower DM, lower pH, and also had the highest lactic acid. Ammonia levels declined when moisture content decreased.