UTILIZATION OF FORMIC ACID TREATED SORGHUM-SUDAN SILAGE BY DAIRY COWS

Abstract

Four methods of ensiling sorghum-sudan grass were compared: A, field wilted to an average moisture content of 69% prior to chopping; B, direct cut and chopped; C, direct cut and chopped with 0.5% w/w of 90% formic acid added at time of ensiling; and D, direct cut and chopped with 1.5% w/w molasses added during the ensiling process. The four silages were fed successively to each of 16 lactating cows over periods of 56 days according to a changeover design. Mean silage dry matter intakes (kg/day) were 10.0a, 9.1b, 9.2b and 9.5ab, and mean milk yields (kg/day) were 16.2a, 16.5a, 17.2b and 16.4a for treatments A, B, C, and D, respectively (where means followed by the same letter were not significantly different; P < 0.05). Digestibilities of dry matter, fiber and energy were significantly lower (P < 0.05) for the formic acid-treated than for the wilted silage. The efficiency of energy utilization for milk yield plus body gain was greater (P < 0.05) for formic acid silage than for any other treatment.