INFLUENCE OF TYPE OF SILAGE BAG ON CHEMICAL COMPOSITION OF ALFALFA SILAGE

Abstract

Second-cut alfalfa in mid-bloom was ensiled in 3.6-m-diameter silage bags to give about 20 t of material per bag. Six bag types were utilized and each was replicated thrice. Bags evaluated were: PolyStor, Silobag, CIL-SB2, CIL-SB3, Visqueen, and AgBag. Ensiled material was assayed for chemical composition, including fermentation products, 2 and 14 mo after ensiling. Silage was also evaluated qualitatively based on smell (ammonia and silage aroma) and appearance (color, spoilage, consistency, and mold) at 8 and 14 mo. At 2 mo, all silages were judged to have met minimum requirements of good silage. However, significant differences in chemical composition suggest potential silage feeding value could be rated:[Formula: see text]Qualitative evaluation after 8 mo suggested silage quality was similar to that determined at 2 mo. However, after 14 mo one bag type contained silage which did not meet minimum requirements for good silage. The unacceptable silage, from PolyStor bags, had high pH as well as low concentrations of lactic acid and total alcohols. Within the five silage types judged to have met minimum standards, there was insufficient difference in chemical composition to suggest differences in potential feeding value. Silage in all bags showed significant deterioration between 8 and 14 mo and it is suggested that to ensure high-quality feed, silage should be fed prior to the summer following bag filling. Key words: Silage bags, silage quality, alfalfa