Current Progressive Dairy digital edition

Don’t upset the digestive microbiome: Utilize direct-fed microbials

Keith A. Bryan, Steve Schwager and John Kurtz Published on 20 October 2015
Dairy cow digestive microbiome

High-producing dairy cows like consistency, but more importantly, the microbiome in the digestive tract of a high-producing dairy cow likes consistency!

The term “microbiome” is used to describe a community of microorganisms living in and on a host, like a cow. There is considerable interest in learning more about how specific microbiomes affect physiological processes of the host, especially high-producing dairy cows.



Consistent ration composition to be digested by the extensive ruminal and post-ruminal microbiome is critical to optimizing nutrient flow for high-producing cows. Although the cow eats, we are essentially feeding this vast pool of microorganisms – the digestive microbiome.

Don’t upset the digestive microbiome

As diligently as we may plan to minimize the number, magnitude or impact of feed changes, when it comes to feeding dairy cows, feed changes are inevitable, especially this time of year. One widely used strategy to manage these changes is to blend the new and old feed for a couple weeks (in some instances, only a few days) in the TMR to help the cow’s digestive microbiome adapt to the change.

Bottom line: Allow sufficient time for the cow’s digestive microbiome to transition and adapt to feed changes.

We also know that when the supply of nutrients to the rumen is reduced or limited, microbial growth and yield is also reduced. Delayed or late feeding, or extended time held away from feed in the holding area or palpation rail also limits nutrient supply.

Bottom line: Don’t allow the cow’s digestive microbiome to run out of feed.


Researchers in Israel found that the relative proportions of two specific bacteria in the ruminal microbiome of a lactating dairy cow were strongly correlated with daily milk fat yield. These results suggest that there is tremendous potential for utilizing direct-fed microbials (DFM or probiotics) to supplement the natural digestive microbiome of the lactating dairy cow.

There are numerous feed additives that feature probiotic bacteria that deliver beneficial effects to dairy cows. Research trials have shown that specific probiotic feed additives have improved animal gut health by regulating pH, scavenging oxygen, binding pathogens and toxins, and inhibiting pathogenic bacteria. These modes of action can result in improved starch and fiber digestibility, and decrease the incidence of sub-acute rumen acidosis (SARA), while field trials have demonstrated a 3- to 4-pound increase in energy corrected milk (ECM).

While there is still a lot to learn about the digestive microbiome of the dairy cow, numerous research studies have shown that supplementing specific probiotics to increase the microbial diversity of the cow’s digestive tract is beneficial. The addition of probiotic supplements being fed in dairy cow diets is sure to increase as producers realize the economic benefits from the adoption of this technology. Additionally, we expect that there will continue to be new developments in this field that will lead to new opportunities for producers to benefit from increasing the diversity of the dairy cow’s natural digestive microbiome.

Bottom line: Inclusion of a science-based, research-proven DFM in the TMR of high-producing dairy cows can yield benefits that exceed production benefits alone.

Don’t upset the digestive microbiome!  PD

References omitted but are available upon request. Click here to email an editor.


Keith A. Bryan, Ph.D., is an Americas technical services manager of silage inoculants and ruminant DFMs for Chr. Hansen Animal Health & Nutrition.

Steve Schwager, PAS, is a regional account manager for Chr. Hansen Animal Health & Nutrition.

John Kurtz is the cattle business manager for Chr. Hansen Animal Health & Nutrition.

PHOTO: Illustration by Kristen Phillips.