Q. How do I know if I’m I getting enough CFUs in my silage inoculant?
A. Colony forming-units (CFUs) are the measurement for microbes in silage inoculants. The accepted minimum standard for driving a rapid pH drop is 100,000 CFUs per gram of fresh forage. Be wary of any inoculant containing less.
To reliably produce silage with good aerobic stability, inoculation with a significantly higher dose rate is necessary. For example, Lactobacillus buchneri 40788 applied at a rate of 400,000 CFUs per gram of forage is the only inoculant bacteria strain reviewed by the FDA and allowed to claim improved aerobic stability. For high-moisture corn (HMC), L. buchneri 40788 should be applied at even higher rate — 600,000 CFUs — to achieve the desired result.
The inoculant product label should clearly list the number of CFUs for each bacterium in the formulation. Furthermore, the manufacturer should be able to provide independent data to support an inoculant’s claims. This research should be from studies performed using the same specific strains of bacteria and the same number of CFUs as the product being purchased.