Gut Check: How DDGS in Cattle Feed Affects Their Microbiome

Beau Callahan in Science & Nature September 2025 • 5 min read.

"Uncover the surprising ways distillers grains plus solubles can alter the bacterial balance in your cattle's rumen and feces, impacting their health and productivity."

The gastrointestinal (GI) tract of ruminants like cattle teems with a diverse microbial population that significantly impacts their health and productivity. This complex ecosystem aids in digestion, nutrient absorption, and immune function. Disruptions to this delicate balance can lead to health issues and reduced performance. Traditionally, understanding these microbial communities has been challenging, relying on culture-dependent methods that only capture a fraction of the total diversity.

However, modern molecular methods, like bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP), offer a more comprehensive view of the microbial landscape. These techniques allow researchers to identify and quantify a wide range of bacterial species, providing valuable insights into the intricate relationships within the gut microbiome.

One dietary component increasingly used in cattle feed is dried distillers grains plus solubles (DDGS), a byproduct of ethanol production. As the use of DDGS rises, it's crucial to understand its effects on the delicate balance of the gastrointestinal microbial population of cattle. This article will delve into a study that examines how different levels of DDGS in cattle feed impact their ruminal and fecal bacterial diversity.

The DDGS Impact: What the Study Revealed?

Surreal image of cow digestive system galaxy influenced by DDGS feed.

A study published in the Journal of Animal Science investigated the effects of DDGS on the gut microbiome of cattle. Researchers divided cattle into three groups, each receiving a different diet: one with no DDGS (control), one with 25% of the concentrate portion replaced with DDGS, and one with 50% DDGS. They then used bTEFAP to analyze the bacterial composition in both the rumen (the first chamber of the cow's stomach) and feces of these animals.

The study revealed several key findings:

Shift in Bacterial Populations: The ruminal and fecal bacterial populations differed significantly between cattle fed DDGS and those in the control group, indicating that DDGS does indeed alter the gut microbiome.
Firmicutes:Bacteroidetes Ratio: The ratio of Firmicutes to Bacteroidetes, two major bacterial phyla in the gut, was smaller in the groups fed 25% and 50% DDGS compared to the control. This ratio is often associated with energy metabolism and obesity in other species, but its specific implications in cattle require further investigation.
Ruminal pH Reduction: Cattle fed the 50% DDGS diet experienced a decrease in ruminal pH compared to the control group. Lower pH can affect the activity of certain microbial species and influence the overall fermentation process in the rumen.
Changes in Genera Abundance: The study identified specific bacterial genera that were affected by DDGS. For instance, Succinivibrio populations in the rumen were reduced with DDGS inclusion, while Prevotella populations increased. In feces, Acinetobacter levels were significantly higher in the DDGS groups.

While the study didn't detect harmful pathogens like E. coli O157:H7 at significantly different levels, the observed shifts in bacterial populations raise important questions about the potential for DDGS to create niches for opportunistic pathogens or alter the overall functionality of the gut microbiome. Understanding these dynamics is crucial for optimizing cattle health and food safety.

The Bigger Picture: Why Gut Health Matters

The study underscores the importance of understanding how dietary changes, such as the inclusion of DDGS, impact the gut microbiome of cattle. By using advanced molecular techniques like bTEFAP, researchers can gain valuable insights into the complex interactions within the gut and identify potential risks or benefits associated with different feeding strategies. This knowledge can then be used to develop more targeted nutritional interventions that promote cattle health, productivity, and food safety. Further research should explore the functional consequences of the observed microbial shifts, focusing on how these changes affect nutrient utilization, immune function, and the overall resilience of the gut ecosystem.

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This article is based on research published under:

DOI-LINK: 10.2527/jas.2010-2900, Alternate LINK

Title: Evaluation Of Bacterial Diversity In The Rumen And Feces Of Cattle Fed Different Levels Of Dried Distillers Grains Plus Solubles Using Bacterial Tag-Encoded Flx Amplicon Pyrosequencing1

Subject: Genetics

Journal: Journal of Animal Science

Publisher: Oxford University Press (OUP)

Authors: T. R. Callaway, S. E. Dowd, T. S. Edrington, R. C. Anderson, N. Krueger, N. Bauer, P. J. Kononoff, D. J. Nisbet

Published: 2010-12-01

Everything You Need To Know

How does the use of dried distillers grains plus solubles (DDGS) in cattle feed affect the bacterial composition in their gut?

Including dried distillers grains plus solubles (DDGS) in cattle feed significantly alters both the ruminal and fecal bacterial populations. A study using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) showed that the bacterial populations in cattle fed DDGS differed from those in the control group. This indicates that DDGS does indeed have an impact on the gut microbiome, specifically affecting the balance and diversity of bacterial species present.

What is the significance of the Firmicutes to Bacteroidetes ratio in cattle when feeding dried distillers grains plus solubles (DDGS)?

The ratio of Firmicutes to Bacteroidetes, two major bacterial phyla, is an indicator of changes in the gut microbiome. The study revealed that the Firmicutes to Bacteroidetes ratio was smaller in cattle groups fed 25% and 50% dried distillers grains plus solubles (DDGS) compared to the control. This ratio is associated with energy metabolism and obesity in other species. While the specific implications in cattle require further investigation, shifts in this ratio suggest alterations in how cattle metabolize energy, which could influence their overall health and productivity. Further research is needed to understand the long-term effects of these changes on nutrient absorption and weight management in cattle.

How does dried distillers grains plus solubles (DDGS) affect the ruminal pH in cattle, and what are the potential implications?

Cattle fed a diet with 50% dried distillers grains plus solubles (DDGS) experienced a decrease in ruminal pH compared to the control group. Lower ruminal pH can affect the activity of certain microbial species and influence the overall fermentation process in the rumen. This change in pH may impact the efficiency of digestion, nutrient utilization, and the balance of the gut microbiome. It could also potentially favor the growth of acid-tolerant bacteria while inhibiting others, leading to further shifts in the microbial community structure.

What specific bacterial genera are most affected by the inclusion of dried distillers grains plus solubles (DDGS) in cattle feed, and why is this important?

The study identified that Succinivibrio populations in the rumen were reduced with dried distillers grains plus solubles (DDGS) inclusion, while Prevotella populations increased. In feces, Acinetobacter levels were significantly higher in the DDGS groups. These changes in genera abundance are important because each genus plays a specific role in the gut ecosystem. For instance, Succinivibrio is involved in succinate metabolism, and Prevotella is known for its role in carbohydrate fermentation. Shifts in these populations can alter the fermentation pathways and nutrient availability in the rumen, potentially affecting the overall health and productivity of the cattle. Monitoring these specific changes can help in understanding the functional consequences of dietary modifications.

What are the broader implications of understanding how dried distillers grains plus solubles (DDGS) impacts the gut microbiome of cattle, and what future research is needed?

Understanding how dried distillers grains plus solubles (DDGS) impacts the gut microbiome of cattle is crucial for optimizing cattle health, productivity, and food safety. By using advanced molecular techniques like bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP), researchers can gain valuable insights into the complex interactions within the gut and identify potential risks or benefits associated with different feeding strategies. Future research should explore the functional consequences of the observed microbial shifts, focusing on how these changes affect nutrient utilization, immune function, and the overall resilience of the gut ecosystem. Additionally, it's important to monitor for potential opportunistic pathogens and understand how DDGS-induced changes may affect their prevalence and impact on cattle health. This knowledge can then be used to develop more targeted nutritional interventions that promote a healthy and balanced gut microbiome, ultimately benefiting the cattle industry and ensuring food safety.