By: Rebecca Konopka
Carter County Extension Agent
As temperatures fall, livestock producers should pay close attention to forages that can cause prussic acid poisoning. Sorghum, sudangrass, sorghum-sudan hybrids, Johnsongrass and wild cherry contain compounds that may release cyanide when plants are damaged by frost, drought or other stress. The toxin can interfere with an animal’s ability to use oxygen and may cause death quickly.
The risk of prussic acid poisoning is highest in the fall because the first frosts and freezes can make these plants especially dangerous. Young shoots and regrowth also may contain higher toxin levels. Remove ruminants from pastures containing high-risk plants when frost is expected, and don’t allow animals to graze those fields at night when a frost is likely.
Testing removes the guesswork from grazing decisions. Before turning livestock into a questionable field, contact your county Extension office. Local extension offices are equipped with Cyanide Field Test kits that can help to assess risk levels. Because toxin levels can vary across a field and change after frost or new growth, follow the sampling instructions carefully and discuss whether additional testing is needed before grazing or feeding the forage.
While waiting for results, keep livestock away from suspect forage. After a light, non-killing frost, wait about two weeks before grazing. Following a killing frost, wait until the plant material is completely dry and brown—generally at least 48 to 72 hours. Do not graze wilted plants or young tillers. For hay, allow the forage to dry thoroughly before baling. If the crop is ensiled, delay feeding for six to eight weeks so the toxic compound has time to dissipate.
Symptoms of prussic acid poisoning may include staggering, labored breathing, foaming at the mouth, spasms, convulsions and collapse but most commonly livestock are simply found dead. Contact a veterinarian immediately if an animal shows these signs.
For help assessing forage risk, collecting a sample or understanding test results, contact the Carter County Extension office. Educational programs of the Cooperative Extension Service serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, religion, political belief, sex, sexual orientation, gender identity, gender expressions, pregnancy, marital status, genetic information, age, veteran status, or physical or mental disability.
Johnsongrass in a hayfield
Upcoming Events:
• Beef Beyond the Pasture – October 26 (Lawrence County Extension Office) & October 29 (Opell Meats) Both evenings start at 6:00 PM. Call 474-6686 to register.
• Little Sandy Beekeepers – November 3 – Members will be making winter feeding cakes at 5:30. Businesses meeting will start at 6:30.
• East KY Hay Contest Awards – November 5 @ 6:00 (Fleming County Extension Office) – Call 474-6686 to register.
