From Mr. Buckeye Ag Radio Network himself, Andy Vance.

Animal health experts want you to get poor quality silage out of your cows’ diet. Not only because of the lower nutritive value, but because it could kill them. Literally. Ohio Agricultural Research and Development Center microbiologist Dr. Jeffrey LeJeune said this week that listeriosis can be caused by such poor silage. What veterinarians often refer to as circling disease because of a common reaction in affected cows, listeriosis is technically caused by Listeria monocytogenes, a bacterium found on plants, in the soil, and in natural waterways. Studies have found the bacterium isolated in manure from dozens of species, and the bacterium is often present without symptom.

Dr. LeJeune says for the most part, exposure to the bacterium is harmless, but “using feed that has been inadequately ensiled and does not reach an acidic pH of less than 5 can pose a problem.” He says that under such conditions, “Listeria naturally present on the feedstuffs can slowly multiply in storage, resulting in a large number of organisms accumulating in feed by late winter and early spring.”

Listeria often presents itself with the symptomatic circling pattern many affected cows walk, but also can lead to late-term abortions, mastitis, and other conditions. Dr. LeJeune suggests that if you experience death loss and suspect listeria, save samples from the deadstock for veterinary analysis and confirmation. To prevent the disease, he suggests taking “precautions when silage is chopped and packed to make sure it reaches the appropriate pH conditions.”