Growing Beef Newsletter
August 2026, Volume 17, Issue 2
Fertilizer and insecticide awareness
Scott Radke, DVM, MS, DABVT Clinical Associate Professor
With the completion of spring and the heat of summer setting in, new toxic concerns have reared up. Both fertilizers and insecticides pose a high risk for cattle, and, although avoidable, poisonings are unfortunately a common occurrence. Over the last several months, multiple situations involving either fertilizers or insecticides have been reported to the Iowa State University Veterinary Diagnostic Laboratory. These cases have resulted in multiple high death loss of otherwise healthy animals.
Fertilizers
With the intense heat of summer, access to water is critical now more than ever. The loss of readily available water as a result of drought or malfunctioning well equipment provides for scenarios of highest risk for one of the most common sources of fertilizer poisoning in cattle -- the supplementation of water in large plastic tanks and equipment previously used for fertilizers. The use of such tanks is tempting as they have immense capacity and are easy to transport. However, even when washed multiple times, these tanks and equipment present a significant risk to cattle. Even steel tanks that have been used to haul fertilizer pose a risk.
Ruminants are particularly susceptible to urea and nitrate as a result of the chemistry that occurs within the rumen. Rapid onset of clinical signs and death is common. Poisoning by either nitrate or urea can result in incoordination and tremors. Those affected by urea may also exhibit stiffening of the forelimbs and prostration along within increased urination, frothing at the mouth, and diarrhea. Cyanotic or “muddy” mucous membranes accompanied by respiratory distress are characteristic of nitrate poisoning. Although signs may be observed with either agent, cattle are often found dead.
Diagnosis of nitrate or urea poisoning involves collection of ocular fluid from deceased individuals. In cases were urea is suspected rumen content should also be collected, sealed, and frozen immediately. A delay in sample collection can result in loss of diagnostic value. Suspected water should also be collected for analysis.
Even though both nitrate and urea poisoning can be treated, both the rapid effects of these compounds and different treatment methods required in cases of combined poisoning can make successful treatment of cattle difficult. Therefore, prevention is critical. Whenever water is provided to cattle in large tanks or trailers, producers should confirm that such equipment, even hoses, did not contain or were not previously used for nitrate or urea fertilizer-based products even if they have been washed. Providing cattle with water from tanks contaminated with fertilizer products is known to cause deaths. A new tank or one that is strictly designated for water should be strongly considered.
Insecticides
With the end of spring and planting season, many producers take time to clean treated seed and insecticide out of planting equipment and storage areas. Great care should be taken when performing these tasks. One of the most common sources of insecticide poisoning in cattle that has a tremendous negative impact, is the accidental incorporation of the insecticide product into animal feed. This usually occurs through a varied combination of unlabeled containers, contaminated equipment such as loader buckets and wagons, and lack of communication between farm personnel. Many pesticides that are granular look like mineral and vitamin premixes making it difficult to tell them apart. Insecticide products specifically designed for direct application to cattle can also be a source of poisoning when incorrect dilutions are made.
The majority of insecticide compounds affect the nervous system, and affected individuals exhibit neurologic complications. Clinical signs of organophosphate (OP) / carbamate poisoning include increased salivation, lacrimation, urination, and defecation (SLUD). Tremoring, convulsions, difficulty breathing, and sudden death are also commonly observed. Tremors and convulsions may be observed with pyrethroid insecticides. Particular attention should be paid to affected cows with nursing calves as some compounds can pass through the milk.
Much like with fertilizers, onset of signs and death is rapid and available treatments are often not able to be provided fast enough. Again, prevention of intoxication is critical. Any containers with insecticide should be clearly labeled and properly stored away from feedstuffs. Unknown material or material in unlabeled containers should never be used for feed. Equipment used for feeding or holding feedstuffs should not be used for insecticide storage or transport. If such equipment must be used for insecticide clean up or transport, then a thorough washing at minimum is required. Clear communication amongst all individuals is critical so that everyone knows where the insecticide is and how it is stored to prevent using it accidentally.
Due to the stability of many insecticides, proper disposal of affected cattle is necessary to prevent relay or secondary poisoning. Cattle should not be rendered. Incineration or complete burial, in accordance with any regulations, is preferred.
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