GROWTH, INTAKE, AND DIGESTIBILITY FROM FORMIC ACID SILAGE VERSUS HAY

Three experiments have been conducted by harvesting forage from a common source and preparing hay and unwilted silage preserved with 0.5% formic acid at ensiling. In each experiment digestibility was measured in 4 × 4 Latin-square trials, while feed intake and growth were measured simultaneously in continuous trials with dairy heifers. Mean daily gains on formic silage were 692 g versus 620 g on control hay. The more rapid gains were made from equal digestible energy intake, which implies a greater efficiency of utilization of digestible energy. The digestibility of energy from the formic silage was 67.1, while that of control hays was 59.4. Although two of the hays incurred some rain damage, the third undamaged hay had a lower digestibility of energy than did its corresponding formic silage. In comparison with previous experiments with animals fed untreated, unwilted silages, these animals fed formic silages consumed more digestible energy, gained more weight, and used the digestible energy more efficiently on a net or gross basis. The formic silages were lower in pH, butyric acid, acetic acid, and am-moniacal nitrogen and higher in lactic acid than untreated, unwilted silages. © 1969, American Dairy Science Association. All rights reserved.