INFLUENCE OF FORMIC ACID AND FORMALIN ON THE PRODUCTION OF ORGANIC ACID IN DIRECT-CUT ALFALFA SILAGE

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 combinations of mixtures were applied to the forage on a fresh weight basis at rates of 0.33, 0.50, and 0.66%. A sample of the treated material was ensiled in test tube silos fitted with fermentation locks. At various time intervals, analyses were made to follow the patterns of organic acid production. In untreated silage, the pH dropped to 4.3 with high lactic acid production, but after 39 days, the pH began to rise as lactic acid was degraded by Clostridia. Formic acid at 0.33 and 0.50% delayed but did not prevent either lactic acid production or subsequent degradation. Formic acid (0.66%) and all rates of formalin depressed lactic acid production. The production of butyric, isobutyric, and isovaleric acids was depressed to low levels only at the 0.66% rate of treatments. Formic acid was more effective than formalin in depressing volatile fatty acids. The formic–formalin mixtures gave results intermediate to separate applications of formic acid and formalin for all parameters analyzed.