Avoid the stink (Dr. Michelle Windle)
“Clostridia” is almost a four-lettered word in today’s silage world. Clostridia bacteria degrade quality and produce butyric acid in silages. However, clostridia challenges can be managed with the right knowledge, tools and strategy.
Clostridia bugs are present everywhere: in the soil, on the plant and on the equipment. The mere presence of Clostridia does not indicate that a butyric fermentation will occur. Crop conditions at harvest dictate if the fermentation will “go butyric.”
Clostridia flourish in wet silages (greater than 60 percent moisture) with a high pH. Examples include rained-on alfalfa, where sugars are often washed out, or a slowly filled or improperly sealed bunker, where the crop continues to respire and use sugars. Fewer fermentable sugars mean a slower pH drop, favoring Clostridial growth and a butyric fermentation.
A butyric fermentation converts sugars or lactic acid into butyric acid. This wastes energy and dry matter (DM) while reducing quality. Lactic fermentation has 100-percent DM recovery and 96-percent energy recovery. Contrast that with a butyric fermentation, which has 66-percent DM recovery and 78-percent energy recovery. Clostridia also degrade proteins, resulting in decreases in protein quality, excess ammonia, and the production of biogenic amines, which can negatively impact rumen fermentation of other, non-butyric feeds in the diet.
Common effects of feeding butyric silages to cows are rumen upsets and decreased intakes, production, components, and milk quality. In extreme situations, health problems, such as ketosis, may occur. Consumption of Clostridia may also increase the risk for hemorrhagic bowel syndrome.
The good news is that, in general, naturally occurring lactic acid bacteria grow faster than Clostridia. These bacteria usually lower the pH fast enough to keep Clostridia from growing. A good “insurance plan” against Clostridia is a hearty, fast-growing, up-front lactic acid bacteria inoculant, such as Crop-N-Rich MTD/1.
If butyric silage is suspected, laboratory organic acid analysis can confirm this. Butyric silages should be diverted away from pre- and post-fresh cows, and animals should not consume more than 50 grams per day of butyric acid. It may be beneficial to “air out” silages, allowing some of the acid to volatilize. Because butyric acid is a strong antifungal, these silages will not spoil while they air out.
Prevention, good silage management and rapid identification of butyric silages is key when it comes to Clostridia in forages.
- Ensure the silage is put up at the proper DM and use a good quality inoculant to decrease pH rapidly.
- Cover and seal the silo quickly and well.
- If you need to ensile silage wetter than recommended, feed it as soon as possible (after two weeks of ensiling) as butyric acid production, in general, takes several months.
- If you suspect a silo is butyric, handle the issue immediately. Time will not improve butyric silage and the amount of butyric acid will only increase.
Contact your Vita Plus consultant or dealer if you have any questions regarding prevention, identification, or handling butyric silages.
Feed quality and nutrition
Forage storage and management