Inoculant Effects on Alfalfa Silage: Fermentation Products and Nutritive Value

• Published in: Journal of dairy science 2007-11, Vol.90 (11), p.5108-5114
• Main Authors: Filya, I., Muck, R.E., Contreras-Govea, F.E.
• Format: Article
• Language: English
• Subjects: alfalfa; Animal productions; Animals; Biological and medical sciences; Cell Wall - chemistry; Feeding. Feeding behavior; Fermentation; Food Handling - methods; Food Microbiology; Fundamental and applied biological sciences. Psychology; Gram-Positive Bacteria - growth & development; Gram-Positive Bacteria - metabolism; lactic acid bacteria; Lactobacillus buchneri; Medicago sativa - chemistry; Medicago sativa - metabolism; Medicago sativa - microbiology; Nitrogen - analysis; Nutritive Value; silage; Silage - analysis; Silage - microbiology; Terrestrial animal productions; Vertebrates; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2006-877

The effect of 14 microbial inoculants on the fermentation and nutritive value of alfalfa silages was studied under laboratory conditions. The first cut (477g of dry matter/kg) and second cut (393g of dry matter/kg) of a second-year alfalfa stand were ensiled in 2 trials. In both trials alfalfa was harvested with standard field equipment. All inoculants were applied at 1.0×106cfu/g of crop. Uninoculated silages served as controls. After inoculants were added, the chopped forages were ensiled in 1.0- and 0.5-L anaerobic glass jars, respectively, at a density of 500g/L. Each trial had 15 treatments (uninoculated control and 14 inoculants), with 4 silos per treatment. Silos were stored for a minimum of 30 d at room temperature (∼22°C). In first-cut silage, all inoculants but one reduced pH relative to the uninoculated control, and all but 2 of the homofermentative strains shifted fermentation toward lactic acid. In second-cut silage, the epiphytic lactic acid bacterial population was 2.7×107 cfu/g, and only commercial inoculants produced significant shifts in fermentation. Overall, microbial inoculants generally had a positive effect on alfalfa silage characteristics in terms of lower pH and shifting fermentation toward lactic acid with homofermentative lactic acid bacteria or toward acetic acid with heterofermentative lactic acid bacteria, Lactobacillus buchneri. These effects were stronger in the commercial products tested. In spite of the positive effects on silage fermentation, 48-h in vitro true DM digestibility was not improved by inoculation with lactic acid bacteria.