By Andi Anderson
As temperatures drop across parts of the region, farmers growing sorghum species are being reminded to watch for frost and manage their forages carefully. Cooler nights and early frost can increase the risk of prussic acid poisoning, a toxic condition that can affect grazing livestock.
Prussic acid, also known as hydrogen cyanide, is a compound that forms when plant cells are damaged by frost or stress. This occurs when dhurrin, a naturally occurring substance in sorghum species, breaks down into prussic acid during cell injury. When animals consume affected plants, the compound interferes with oxygen transfer in their bodies, which can lead to rapid illness or even death.
High-risk crops include sorghum, sudangrass, and sorghum-sudangrass hybrids. Young, fast-growing plants or regrowth after a frost event are especially prone to prussic acid accumulation.
Producers are urged not to graze or green-chop sorghum species immediately after frost. Instead, they should wait at least 7–10 days after a killing frost or until the plant has completely dried and turned brown before feeding it to livestock.
Once properly dried, prussic acid dissipates, making the forage safe to feed. However, ensiling or haying sorghum species also helps reduce toxin levels, as the fermentation process further breaks down harmful compounds.
Livestock producers should continue monitoring weather forecasts and prepare to remove animals from pastures if frost is expected. Working closely with Extension specialists or local agronomists can help ensure safe feeding strategies through changing fall conditions.
By understanding how prussic acid forms and following safe management practices, farmers can protect both their livestock and forage quality as frost season sets in.
Photo Credit: istock-mailson-pignata
Categories: Ohio, Rural Lifestyle, Farm Safety