INFLUENCE OF FORMIC ACID AND FORMALIN ON QUALITY OF DIRECT-CUT ALFALFA SILAGE

Abstract

Early bloom alfalfa (Medicago sativa cult Saranac), at 22.5% dry matter, was harvested with a forage harvester. Formic acid (85% solution) and formalin (37.5% solution) and various mixtures were applied to the herbage, on a fresh weight basis, at rates of 0.33, 0.50, and 0.66%. The material was ensiled in sealed plastic-lined barrels holding 150 kg and fitted with fermentation locks. After 130 days, the quality of the treated and untreated silages was examined by comparing organic acid and ammoniacal-nitrogen contents. With formic treatments, an immediate drop in pH to 4.76, 4.20, and 3.93 was observed with rates of 0.33, 0.50, and 0.66%, respectively. Formalin had no effect on pH. Lactic acid contents were lower with formalin and the 0.66% formic but higher with 0.33 and 0.50% formic than in untreated silage. The volatile fatty acids were reduced equally by both formic acid and formalin. Increased rates of application reduced these acids. The ammoniacal-nitrogen contents decreased with increased application rates. Amounts of 14.11, 2.80, and 5.73% of total nitrogen were found in untreated, 0.66% formic acid-treated, and 0.66% formalin-treated silages, respectively. The various formic–formalin mixtures produced results intermediate to separate applications of formic and formalin for all parameters analyzed.