With direct-fed microbials, or DFMs, it’s difficult to know exactly what you are getting unless you ask the right questions.

Different manufacturers offer different levels of quality, and frankly there have been some “snake-oil” salesmen out there who have given the products a bad name. Needless to say, DFMs are a gray area for many producers.

If the product is based on bacteria, be sure to ask the company what it is doing to keep the bacteria alive and viable by the time you use it, says Mike Hutjens, extension dairy specialist at the University of Illinois. The package will give you a bit of clue, he says. Does it have an expiration date like a milk product? 

And, does the company have research data to back up its claims? Much of that research should be from independent sources, such as universities.

This is where you have to be as discerning as possible. Does the product have the same strains of bacteria that were in the research study? Does it supply bacteria in similar quantities? Is the product intended for the same purpose on your farm?

Additional questions:

Consider asking the following questions. (Note: these are intended to address bacteria-based direct-fed microbial products. There are additional questions to ask with regard to live yeast and yeast culture products, but those will not be addressed here.)

What bacteria (and what strains) are in the product?

Don’t just accept the general term “Lactobacillus” for an answer — there are different strains of Lactobacillus. Some strains work better than others.  

What does the company do to ensure the bacteria stay alive during shipping and storage?

Does it have shelf-life information? Granted, it will probably be their own in-house data, so it’s important to deal with a reputable company that you can trust. Do their studies replicate the storage conditions at your farm? “Viability of DFM products has improved over the past several years, but each product has inherent storage recommendations that should be followed, as microorganisms can be highly sensitive to heat and moisture,” points out Limin Kung, dairy scientist at the University of Delaware.

Are their viability claims based solely on the “time of manufacture?”

This is a potential loophole. Manufacturers are required to guarantee the level of viable bacteria at the time of manufacture, but those same bacteria may be dead a week later. Ask instead for a guaranteed shelf life or expiration date.

What type of packaging do they offer?

Some bagged products have a polyethylene liner. Make sure that the liner has a moisture vapor transfer rate, or MVTR, of zero, so no moisture can seep through and de-stabilize the product. Foil is a great moisture barrier. Watch out for any packaging that has seams or stitches, especially if it is the layer in direct contact with the product, because moisture can seep through the stitching.

Do they make a claim for “total microbial activity”?

Don’t be fooled. Total guarantees can be masked by adding more of the higher-stability organism, such as bacillus, while all other organisms in the package are dead. If they list a multitude of microorganisms on the label, make sure that they guarantee each and every one.