Dry Matter Content and Additives with Different Modes of Action Modify the Preservation Characteristics of Grass Silage

Abstract

Two experiments evaluated how grass silage quality can be manipulated by various management options. In Experiment 1, silage characteristics were evaluated at two dry matter (DM) contents and treated with additives presenting different modes of action. Timothy grass was ensiled at low (224 g/kg) and high (534 g/kg) DM contents and five additives were applied: 1. control (C), 2. homofermentative lactic acid bacteria inoculant (HO), 3. heterofermentative lactic acid bacteria inoculant (HE), 4. salt-based additive (SA) and 5. Formic- and propionic-acid-based additive (FPA). A higher DM content and FPA restricted silage fermentation, and additive effects were generally greater in low rather than high DM silages. The chemical additives SA and FPA resulted in the highest aerobic stability, while the HE improved it at a high DM content. In Experiment 2, the low DM content grass was ensiled utilizing resin acids, as follows: 1. C, 2. FPA, 3. Resin acid oil (FOR) at 13 L/t, 4. FOR at 26 L/t, 5. Resin acid soluble in water (ROS) at 13 L/t and 6. ROS at 26 L/t. Wilting combined with additives improved the preservation characteristics of grass silages (Experiment 1), but resin acid products failed to modify silage fermentation compared to the control (Experiment 2).