Watch for lead poisoning in pasture cattle

The Kansas State University Veterinary Diagnostic Laboratory diagnoses many kinds of illnesses throughout a given year, but the one witnessed frequently this past spring in cattle was lead poisoning.

“Lead poisoning is the No. 1 poisoning we diagnose in the diagnostic lab,” said Gregg Hanzlicek, director of production animal field investigations with the lab. “This past spring, we had several cases of spring-born calves diagnosed with lead poisoning shortly after going to pasture.”

Lead poisoning is difficult to identify and is often fatal. For this reason, it’s important for producers to be vigilant in monitoring for differences in behavior.

“Like many poisonings, unfortunately one of the most common signs is finding one or more dead animals in the pasture. For those that aren’t found dead, another clinical sign is a difference in behavior,” Hanzlicek said. “The calves or cows may stumble or stagger; they may then become recumbent followed by convulsions.  One of the major classical signs of lead poisoning in cattle is blindness.”

Within a day or two of ingestion, the signs of lead poisoning will begin to show, either by death or by those symptoms, he said.

Lead poisoning is diagnosed most often in young calves. Since medicinal treatment for lead poisoning is largely ineffective, prevention is the best control method. Identifying how cattle acquire lead poisoning can give producers a look into how to prevent it.

“The only way a calf or a cow can become poisoned is if they ingest the lead. Any age animal can ingest it and become poisoned, but the reason we see it more often in calves is for a couple of reasons,” Hanzlicek said. “Newborn calves going to pasture are curious, so they’re mouthing things and trying to eat things older animals normally wouldn’t. When we have hard rains, sometimes the rain washes uncovers sources of lead, then the calf has exposure to it.”

Monitoring your pasture for items that contain lead can decrease the chance of poisoning.

“The most common sources of lead toxicity in calves and cows are old batteries from trucks and cars that have been disposed of in the pasture. Calves either lick on the battery posts or lick on the plates in the battery. There are other sources such as linoleum or old caulking materials,” Hanzlicek said. “To prevent it, if you know that you have a site where things were disposed of in the pasture, it’s a good idea to fence the area to prevent animals from having access.”

Though prevention is the best treatment, there are things producers can do should they suspect that their cattle contracted lead poisoning.

“With the fact that we have smartphones and these devices have video capability, I would advise the producer to take a relatively long video of the animal and send it to their veterinarian,” Hanzlicek said.

The veterinarian can then decide, based on the video, if more testing is needed to find the true problem.

“There are a couple of good blood tests that are definitive for lead poisoning for diagnosing it in live animals,” Hanzlicek said. “For animals that are found dead, we typically like liver and kidney tissue sent in to determine the lead level of those tissues.”

Lead poisoning can be confused with other diseases, so when these symptoms arise, it’s important to identify what is ailing the animal.

“Some of the things that can be confused with lead poisoning is a neurologic disease called Polioencephalomalacia, another one is rabies and the third is low magnesium,” Hanzlicek said. “The point is, because you see the clinical signs, you can’t just think of lead poisoning. There’s a whole bunch of other diseases to take into consideration. The best source of advice is your veterinarian as he or she has been trained to recognize a diverse number of diseases. Many diseases appear with similar clinical signs to the lay persons’ eye.”

Contact the Kansas State Veterinary Diagnostic Laboratory for more information.