Effect of Mixing Alfalfa (Medicago sativa L.) with Orchardgrass (Dactylis glomerata L.) on the Fermentation Profile of Silage when Harvested Three Times a Year

Abstract

We explored the effect of mixing alfalfa with orchardgrass in different ratios on the fermentation profile of silage when harvested three times a year. Alfalfa and orchardgrass were harvested and mixed in fresh weight ratios of 100 : 0 (O0), 70 : 30 (O30), 50 : 50 (O50), 30 : 70 (O70), and 0 : 100 (O100) for the 1st, 2nd, and 3rd harvests, respectively. After mixing, materials were chopped to 2 cm, wilted for 24 h, and ensiled for 90 days. The wilted materials with a greater proportion of orchardgrass had lower crude protein content and buffering capacity, and higher water soluble carbohydrate content, regardless of the harvest number. The materials of the 1st harvest had lower dry matter content and higher water soluble carbohydrate content than those of 2nd and 3rd harvests for all mixing ratios. With an increasing proportion of orchardgrass, the silage lactic acid content increased, and pH decreased for the 1st harvest. A V-score of more than 60 was observed in O70-100 of the 1st harvest, which indicated that silage fermentation quality was better when alfalfa was ensiled in a mixture with about 70% orchardgrass. On the other hand, materials were not fermented well for the 2nd and 3rd harvests, regardless of the orchardgrass ratios.