The Effects of Combination of Lactic Acid-producing Bacteria and Hydrolytic Enzyme Inoculants on Ensiling Characteristics of Alfalfa and Corn
Prior to ensiling, inoculants containing lactic acid-producing bacteria (LAB) may be used to promote greater, more rapid lactic acid production causing a faster pH decline, possibly resulting in less DM and nutrient loss. The inclusion of hydrolytic enzymes may increase simple carbohydrate availability, further increasing fermentation rate and pH decline. To test the effects of an inoculant containing four species of LAB and four hydrolytic enzymes, green chopped whole plant corn and alfalfa were treated with water (control) or with water containing the inoculant (treatment), resulting in forage that had 33% DM or 42% DM for corn and alfalfa, respectively. Each forage was packed into mini-silos (1206 cm3 volume; n = 3 / treatment per date) to monitor rate of fermentation. The pH was measured on d 1, 2, 3, 7, 13, 17, 21, 28, 45 for alfalfa and on d 1, 2, 3, 7, 10, 17, 28, 45 for corn. Data were analyzed using PROC NLIN and PROC MIXED of SAS significance declared when α = 0.05. The rate of decline to terminal pH was faster (P < 0.01) in the treatment than control in alfalfa, but demonstrated no difference for corn (P = 0.91). Additionally, buckets (n = 5 per treatment; 21,504 cm3 volume) of each forage were ensiled to measure effect on nutrient composition (DM, CP, ammonia, starch in the corn, and sugar, in the alfalfa) and pH after 59 days of fermentation. The pH of the treatment tended to be lower than control in alfalfa buckets (P = 0.07) on d 59 but did not differ between treatments in corn (P = 0.92). The percent DM and DM loss did not differ (P > 0.5) between treatments for either alfalfa or corn. The percent sugar and starch did not differ (P > 0.58) between treatments for alfalfa and corn, respectively. Crude protein content of alfalfa was lower (P < 0.01) in the treatment than control (13.3 vs. 13.0 ± 0.06%) but did not differ (P = 0.11) between treatments in corn. Ammonia content did not differ (P> 0.13) between treatments for both alfalfa and corn. The inoculant appeared to affect the rate of decline to terminal pH in the alfalfa, but not corn, while having little to no effect on nutrient composition of either ensiled forage.
Keywords: silage, pH, inoculants