Windle: Managing Your Inoculants: Getting the Biggest Value Back From Your Investment

Investing in microbial inoculants can pay off through improved fermentation and aerobic stability.  However, properly managing those inoculants is key to getting the biggest value back from that investment.

That’s according to Michelle Windle, a graduate student working with Dr. Limin Kung in the Dairy Nutrition and Silage Fermentation Lab at the University of Delaware.  Windle cited several steps harvesters and producers can take to get the most value from their inoculants.

Choose the best inoculant
Consider your goals for the inoculant.  Will you be feeding this forage early?  If so, improved upfront fermentation from a homolactic bacteria, such as L. plantarum MTD/1, is what you need.  If you know you’ll be feeding the forage later when temperatures are higher, aerobic stability is the main objective and L. buchneri 40788 is the inoculant to choose.

Before purchasing an inoculant, Windle recommends doing your research and make sure the inoculant is proven through many peer-reviewed efficacy trials.  Remember that different strains may have the same name, but not the same efficacy.  Make sure you are purchasing the proven strain.

“Buying on price alone should be avoided,” she said.  “Look for return on your investment.”

Storage
Windle reminds harvesters that bacteria are susceptible to the elements.  Excessive heat and moisture during storage decreases viability.  Although some inoculants can be stored frozen, she warns that repeated freeze-thaw cycles can reduce viability.

Water conditions in the applicator tank
Bacteria are living things, so harsh environments can significantly limit their activity.  Make sure you adequately rinse the applicator tank after cleaning it with a hydrogen peroxide or chlorine solution as these compounds can kill the inoculant bacteria.

Hot water can also have a negative impact.  In a field study, Windle found that the numbers of bacteria were lower in tanks with high water temperatures.  In fact, she started observing issues when water temperatures reached 92 to 95 degrees.  She said tanks hung against the chopper engine were the hottest and tended to have the lowest bacteria counts.  She recommends putting frozen soda bottles in the applicator tank to keep the water cool and regularly checking the temperature.

Other factors
Liquid and dry inoculants will perform differently based on the condition of the forage.  Dry inoculants rely solely on the moisture of the crop, so they perform best when ensiling at a low dry matter content (30 to 35 percent).  When the dry matter increases above 40 percent, dry inoculants work slower.  Because liquid bacteria already have a source of water, they perform well in both conditions provided they are properly stored and mixed.

Finally, Windle reminds harvesters to apply inoculants at the correct application rate; applying at a lower rate can reduce its effectiveness.  Calibrate the applicator frequently to make sure you’re hitting your targets.  Inoculants can be applied directly to bunks, piles, bags or at towers as long as you can assure adequate distribution throughout the whole forage.  Application at the chopper is preferred as it provides the best distribution.

“We’re playing a numbers game here and a dose game,” Windle said.  “We need to make sure we’re getting the right amount of bacteria where they need to work.”