“How can a silage inoculant affect neutral detergent fiber (NDF) digestibility?“
A quality, research-proven inoculant can increase neutral detergent fiber (NDF) digestibility in the finished silage because of better preservation of the most readily digestible NDF fractions due to a faster, more efficient homolactic-driven fermentation during the initial ensiling. In addition, a quality inoculant can help prevent the growth of spoilage organisms once the silage is opened at feedout. Look for independent data to validate the efficacy of the inoculant in achieving these twin goals.
The enzyme activities in some silage inoculants can help improve access of microbes in the rumen to fiber fractions by “pre-digesting” them. However, enzyme effects on NDF digestibility are quite subtle. Again, it is important to ask to see independent data validating claims made and also to look for guaranteed enzyme activity levels on the product label. Without a guarantee, assume there is nothing there!
A study published in the Journal of Dairy Science showed some of the lactic bacteria used in inoculants can increase dry matter (DM) digestibility and NDF digestibility in the rumen. The research examined 10 lactic acid bacteria (LAB) strains from commercial inoculants. Results showed that L. buchneri 40788 specifically resulted in the highest digestibility of DM and NDF in wheat and corn silages, respectively.1
My takeaway message is that high quality silage inoculants can improve NDF digestibility. Ask to see data to validate how a particular product has been proven to have beneficial effects. At the end of the day, the improvement may be due to better retention of digestible nutrients, or direct enzyme effects in making the NDF more digestible, or by some direct effect of the bacteria in the inoculant themselves, or a combination of any or all of these!
The Silage Dr.
1 Weinberg, ZG, et al. Effect of lactic acid bacteria inoculants on in vitro digestibility of wheat and corn silages. J. Dairy Sci. 2007;90:4754–4762.