An Iowa State University veterinarian is urging cattle producers to take additional precautions around fertilizers and insecticides following several poisoning cases involving significant death losses.
Dr. Scott Radke, a clinical associate professor at Iowa State University, said fertilizers and insecticides can pose serious risks to cattle during the summer. In an article published by the Iowa Beef Center, Radke said many poisonings are preventable but can progress too quickly for treatment to be effective.
Fertilizer contamination
Hot weather makes reliable access to clean water especially important. When drought or equipment problems disrupt normal water supplies, producers may be tempted to use large tanks or trailers that previously held fertilizer.
Radke warned that equipment used to store or transport fertilizer can remain hazardous even after repeated washing. That includes plastic tanks, steel tanks, hoses and other equipment.
Ruminants are particularly vulnerable to nitrate and urea because of the chemical processes that occur in the rumen. Poisoning can cause incoordination, tremors and rapid death.
Cattle exposed to urea may also experience stiffened forelimbs, collapse, increased urination, frothing at the mouth and diarrhea. Nitrate poisoning may cause breathing problems and blue-gray or “muddy” mucous membranes. In some cases, the first sign of a problem is finding cattle dead.
Producers should verify that tanks, trailers and hoses used to provide water have never held nitrate- or urea-based fertilizer. Radke recommended using new equipment or tanks designated exclusively for livestock water.
Insecticide exposure
Insecticides can also enter cattle feed accidentally as producers clean planting equipment and storage areas after the spring planting season.
Poisonings commonly occur when insecticides are placed in unlabeled containers, transported with equipment also used for feed or mistakenly mixed into a ration. Some granular pesticides resemble mineral and vitamin premixes, making them difficult to distinguish.
Products intended for direct application to cattle can also cause poisoning if they are mixed or diluted incorrectly.
Many insecticides affect the nervous system. Signs of organophosphate or carbamate poisoning can include excessive salivation, tearing, urination and defecation. Cattle may also experience tremors, convulsions, breathing difficulties or sudden death. Pyrethroid insecticides can also cause tremors and convulsions.
Producers should closely monitor nursing calves when a cow is exposed because some insecticides can pass through milk.
Radke recommended clearly labeling and properly storing all insecticides away from feed. Unknown substances or materials in unlabeled containers should never be added to cattle feed. Equipment used to handle feed should not be used to store or transport insecticides.
Clear communication among employees and family members is also important so everyone knows where insecticides are stored and how they are handled.
Because many insecticides remain stable after an animal dies, affected cattle must be disposed of properly to prevent secondary poisoning. Radke said those animals should not be rendered. Incineration or complete burial, when allowed under applicable regulations, is preferred.
Producers who suspect poisoning should immediately contact their veterinarian and a veterinary diagnostic laboratory.
This story is based on information from Dr. Scott Radke published in the August 2026 edition of the Iowa Beef Center’s Growing Beef newsletter.
