Current Progressive Dairy digital edition

Take steps to limit clostridia

Tom Rehberger for Progressive Dairy Published on 25 October 2021

Managing the welfare and resiliency of cows on a dairy involves a series of routine daily tasks, such as feeding, milking and general herd care. Whether they have a few family members or a team of 200 employees, producers typically establish protocols to complete tasks efficiently while maintaining animal health and productivity. But some feed-management protocols designed to maximize labor efficiency can actually increase levels of harmful bacteria in the total mixed ration (TMR), including clostridia.

For example, defacing silage from the bunker only once a day exposes silage to oxygen initially, which allows yeast to flourish resulting in heating and depletion of oxygen, which creates an ideal environment for clostridia to grow. When it comes to pathogens, few are more destructive and invasive than clostridia. Understanding clostridia is key to developing a protocol to limit its effect.



Understanding clostridia

There are more than 100 species of clostridia, made up of pathogenic and non-pathogenic organisms. Clostridia are gram-positive, spore-forming, anaerobic bacteria commonly found in soil. The tricky part is that as spore formers, they can hide out as spores and withstand almost any environment. That’s why they are present almost everywhere, including in manure, soil, plants, feed ingredients, TMRs and virtually everywhere else.

Inside the animal, pathogenic clostridia work by attacking the barrier that protects the animal from outside organisms. These pathogenic clostridia produce enzymes that break down the mucous layer protecting the epithelial cells lining the gastrointestinal (GI) tract. As the layer is removed, these cells become exposed and are broken down even further, including the tight junctions that keep the cells together and form a barrier against outside invasion from other harmful organisms. Left unrestricted, this allows for the free flow of toxins and bacteria, creating systemic infection and rapid death.

Even though an infection may be subclinical early on, animals may still exhibit symptoms, including reduced feed intake and decreased productivity. As infections advance, they can also result in necrotic enteritis, malignant edema, abomasal disease, botulism, black leg and hemorrhagic bowel syndrome (HBS).

It’s in your feed

In a study conducted by our company, we took more than 20,000 fecal samples from 509 farms across 30 states. Of those samples, 98% contained clostridia, and 80% of those contained Clostridium perfringens. Nearly all of those C. perfringens were type A, which is the strain that leads to HBS. Even though the number of dairies carrying clostridia was high, there was still wide variation on many dairies and often even within the same production group. This is likely due to different rations fed to each group.

In fact, when samples were taken from fermented feeds (haylage and corn silage) and the TMR, the TMR carried the highest levels of clostridia by a large margin. That begs the question: How can the TMR carry clostridia if air can get into the ration? In theory, this would create an oxygen-rich environment where clostridia could not survive. While the answer is unclear, it is assumed that other organisms, such as yeast, grow within the TMR consuming oxygen to a point where clostridia can grow and proliferate. An ideal situation for these organisms to grow occurs when cows are fed only once per day and especially if feed is not stirred or pushed up throughout the day to allow oxygen to penetrate the pile.


Clostridia levels in the TMR can be especially harmful to cows that consume it, even if clostridia remain at very low levels. Even if the clostridia count in a ration is 100 colony-forming units per gram (CFU/g), if a cow eats 100 pounds of feed per day, the total count can be well over 4 million CFUs based on the volume of feed consumed.

Bacillus can control clostridia

If clostridia is in your TMR, your cows could be consuming high levels every day. Controlling the impact of clostridia infection means taking steps to build resiliency inside your herd. Here are a few feed-management protocols to consider to reduce clostridia levels:

  • Deface more frequently. Defacing a forage pile only once per day leaves a pile of loose forage on the storage floor, open to the air and organisms that thrive in the presence of oxygen. As bacteria consume the oxygen, the anerobic environment is ideal for clostridia to grow. Avoid this by defacing forage piles more frequently and only creating piles you can feed quickly.
  • Feed frequently. Or, if you are feeding once per day, push the pile up frequently to allow oxygen to penetrate the pile and impair clostridia growth.
  • Add feed ingredients. Products that contain bacillus target toxigenic and non-toxigenic clostridia. Like clostridia, bacillus are spore formers and can survive in many environments, including in an animal’s GI tract. Bacillus help control clostridial populations by producing many antimicrobial compounds. This includes lipopeptides that anchor within cell membranes and help improve cell structure, polyketides that inhibit protein synthesis so cells can’t replicate and peptides that scavenge iron so it’s less available to pathogens.

Research shows that bacillus strains found in our product can increase the types of proteins used to tighten junctions between cells responsible for creating a barrier that prevents pathogenic bacteria, like C. perfringens, from entering the animal. Feeding these can help your cows become more resilient to infections from pathogens such as clostridia. More-resilient cows have more-consistent feed intakes and fewer off-feed events. This leads to a decrease in issues resulting from a compromised GI tract and, subsequently, fewer cows in the sick pen. And, as clostridia levels decline in the presence of bacillus, fiber-degrading bacteria are allowed to proliferate, including those that break down cellulose and hemicellulose in the GI tract.

It’s important to note that the unique microbial makeup of your dairy changes over time. There are many different strains of bacillus with different functionalities that enable certain strains to perform better in certain situations. As the diversity of your environment changes over time, you’ll want to stay on top of formulations that optimize the inhibition of pathogens.

Clostridia is a devastating, invasive bacteria that doesn’t need any additional help to colonize and cause damage inside your cows. Take the necessary steps to make sure you aren’t delivering these harmful pathogens in greater numbers to your cows.  end mark

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


Tom Rehberger
  • Tom Rehberger

  • Director for Innovation and Product Development
  • Arm & Hammer Animal and Food Production
  • Email Tom Rehberger