The effect of formalin and lower volatile fatty acids on silage fermentation

Lolium multiflorum was ensiled in 3 kg capacity PVC silos after treatment with formalin, formic acid, acetic acid and propionic acid applied singly and in mixtures of two, three and four at a constant application rate of 4.5 g kg−1 fresh grass. The extent of fermentation was assessed by measuring pH, WSC, VN and TSN, and by microbiological analysis of total microorganisms and yeasts. The stability of the silages on exposure to air was measured using a specially constructed temperature recording apparatus. All additives restricted fermentation, although acetic acid and propionic acid were less effective than formalin, formic acid and mixtures of additives. The most aerobically stable silages were those treated with propionic acid, formic/acetic acids, and formic/acetic/propionic acids.