Silage fermentation quality in whole plant maize inoculated with a novel formulation of a biological inoculant with the recently EU-authorized Lactobacillus kefiri

Abstract

Introduction Multi-strain silage inoculants composed of homo- and heterofermentative Lactic Acid Bacteria (LAB) are the most prevalent biological silage inoculants today. Lactic acid, the main metabolite of homofermentative LAB lowers the pH value of silage and improves feed palatability (Krizsan et al., 2007). Unfortunately, high levels of lactic acid make silages more susceptible to aerobic spoilage (McDonald, 1991). Acetic acid is a heterofermentative metabolite which directly inhibits the growth of many spoilage bacteria, yeast and fungi, thereby prolonging the aerobic stability (or shelf life) of silage (McDonald, 1991). A good balance between lactic acid and acetic acid and homofermentative and heterofermentative silage inoculant strains is essential to achieve excellent palatability and aerobic stability. We tested a novel formulation of a biological silage inoculant for its effect on the fermentation quality of whole plant maize silage in a small-scale laboratory trial as well as in a large-scale trench silo. Materials and methods The laboratory scale silage experiment followed a randomized block design (2x1x10). Whole plant maize silage was either treated with the silage inoculant or left untreated (control). Each treatment was tested in 10 replicates (5 for testing nutrient composition and fermentation characteristics, and 5 for testing aerobic stability) during a 90 day experimental period (at constant 20°C) followed by an 11 day aerobic stability test. Mini-silos (glass jars closed with caps) with a volume of 3 litre with were fully filled at a density of 1kg DM 5L-1 (2.06-2.09 kg forage at DM content 35.5 %). The mini-silos were closed not later than 30 minutes after filling. In addition, 5 whole crop maize samples were collected [...].