Effects of Applying Lactic Acid Bacteria and Molasses on the Fermentation Quality, Protein Fractions and In Vitro Digestibility of Baled Alfalfa Silage

Abstract

Alfalfa sometimes cannot be harvested in time due to the rainy season. To improve the fermentation quality, protein quality and digestibility of alfalfa silage harvested late, Lactobacillus plantarum (LP) and molasses were applied in an actual production process in this study. Alfalfa harvested at the full bloom stage was ensiled with (1) distilled water (control), (2) 1 × 106 colony-forming units LP/g fresh matter, (3) 15 g molasses/kg fresh matter (M) or (4) LP + M (LPM) for 55 days. Alfalfa ensiled with LP and/or molasses showed significantly lower pH and ammonia nitrogen contents than the control silage (p < 0.05). All additive treatments decreased nonprotein nitrogen contents and preserved more true protein (p < 0.05). However, molasses increased the acid detergent insoluble nitrogen content in the protein fractions (p < 0.05). The LP significantly improved the maximal cumulative gas production and the maximum gas production rate (p < 0.05) in the in vitro trial. Finally, both LP and molasses improved the neutral detergent fiber digestibility of the alfalfa silage (p < 0.05). The LP and molasses improved fermentation quality and digestibility and preserved more true protein in baled alfalfa silage harvested late in an actual production process. The LP utilized the excessive molasses and partially ameliorated its negative effects of causing higher acid detergent insoluble nitrogen content.