Signs of Clostridial Fermentation in Baleage Part I

It’s the wee hours of the morning and it’s time to feed the cows. You head on out to the skid steer and retrieve a bale of baleage. You’re now at the manger/TMR mixer and slice the bale open…. a rancid, putrid smell looms as the plastic is sliced away. You normally can’t miss the rancid smell but on this day your sinuses are quite full and you don’t detect the odor. As you slice through the baler twine the baleage has a tacky, sticky feel to it with some discoloration in the forage that’s not the norm but the light is dim as it’s the early hours of the morning and your gloves keep the sticky feel and rancid smell from your hands. You roll the bale on out and the cows go to town.

The following morning you retrace your same routine as you have everyday prior and head out to begin feeding the cows. As you pull up to the manger you notice a few cows are off. They seem uncomfortable. No cud chewing, no ambition to eat. Then you see that one of the cows has passed on to the green acres in the sky…

This is a farmers worse nightmare. A barn full of ill animals and only time and treatment will determine the outcome. The cause is an abnormal fermentation that took place during the harvesting/storage phase of the forage. Let’s start with what is “normal”. Normal fermentation takes place when anaerobic bacteria (those that live without air) convert sugars in the forage to lactic acid which in turn lowers the pH and preserves the forage as silage, with full fermentation completed within 6-8 weeks. This fermentation process is known as lactate fermentation.

One of the “abnormal fermentations” that could take place is clostridial fermentation resulting in botulism. Botulism is a disease caused by one of the most potent toxins known to man. This toxin is produced by Clostridium botulinum, a spore-forming anaerobic Gram positive rod. These spores are found everywhere in the soil and contaminate baleage during harvest, often by raking up dirt into the forage. In the absence of oxygen (as is found in wrapped hay ie: baleage) and a pH greater than 4.5 (poor fermentation), the spores enter a vegetative state, multiply and produce toxin.

There are seven types of botulinum toxins. Types A, B, E and F can infect humans. Types C and D are found in poultry, wild birds, mink and their excrement. Type E is related to fish and avian. In instances where an outbreak of a known strain of botulism is suspected, an antiserum can be used for treatment, but oftentimes it’s just too late. Even miniscule amounts of the botulinum toxin can decimate a barn full of livestock. It is not uncommon to read about situations where hundreds of cattle and horses have died within hours of eating contaminated feed. In fact, if you have ever heard the rumor that baleage is not safe to feed to horses, it’s probably because of this reason as horses tend to be much more sensitive to the botulism toxin.


Clostridial fermentation can wreck havoc if fed to your livestock. It’s not worth taking the risk if you believe you may have some questionable baleage. The initial signs that will be noticed out on the farm of a clostridial fermentation in baleage will rely on your senses and experience. First is the smell. The bale will have an odor far from pleasant. It may smell “fishy” or “spoiled” . It will not be a pleasant smell. Second is touch. As you handle the baleage it will have a tacky, sticky or slimy feel to it. Again the odor will definitely permeate your clothing and skin. Last is sight, often but not always a clostridial fermentation will change the color of the baleage to a black, dark green/black or dark brown/green.

If there is any question in your mind if the baleage properly fermented hold off on that bale and retrieve a bale that doesn’t contain these characteristics. It’s not worth taking the risk of possibly creating a barn of sick or dead animals.

Call one of our extension agents to come on out and take a sample to be sent off for a fermentation analysis. We will be more than happy to answer any questions you may have. You can also email me @ [email protected]

This blog post is first in a series. There will be follow up posts getting more in-depth on types and causes of clostridial fermentation, diagnosis of abnormal fermentation and the particular consequences it may have on livestock health once consumed and how to avoid this fermentation in the future.

Can’t wait and want to learn more now? Below you will find some helpful links:





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