Discussing the potential for probiotics to fit as feed additives in dairy cow diets, University of Illinois professor emeritus Dr. Mike Hutjens told a knowledge nook audience at the World Dairy Expo that feed additives can be effective and economic additions to balanced rations.

As a key to making the decision to add probiotics, Hutjens said producers need to look at the four "Rs" -- response (why is the product working), return (what is the cost:benefit ratio of using the product), research (what is the impact of the product) and records (what metrics will be used on-farm to monitor the success of the product).

He noted that the current themes/focus areas in the probiotic space include:

* Stabilizing rumen fermentation, including reducing diurnal variation, maintaining rumen pH above 5.8 and avoiding the production of trans acids;

* "Controlling" lactic acid production, which has implications for rumen pH and ruminal acidosis;

* Stimulating lactic acid utilizers via the production of lactic acid, and

* Combining feed additive types, such as bacteria, yeast products and antimicrobials.

According to Hutjens, certain periods may see the most benefit of supplemental probiotics in dairy nutrition, including high-stress times such as the neonatal period for calves, postweaning, after transport, heat stress, the transition period around freshening and following metabolic disorders.

Dr. Keith Bryan, technical service specialist with Chr. Hansen, followed Hutjens and noted that probiotics can help support "normal" dairy cows by benefiting the cow's microbiota.

Bryan said the microbiota has been found to be crucial for immunologic, hormonal and metabolic homeostasis of the host. He explained that two of the more common probiotic organisms -- lactobacilli and bacilli -- provide complementarity and microbial diversity in the gastrointestinal tract. Lactobacilli interact with host tissues to support normal gut functions such as tight junctions, mucus production, gut signaling and pathogen control, Bryan explained, and bacilli interact with each other to form biofilms and produce enzymes to digest complex nutrients.

Hutjens concluded that dairy producers who decide to utilize probiotics in their rations need to monitor the product response on their farms and continue to monitor published product research.