An Oklahoma cattle producer recently encountered an unusual sudden death loss of more than 10 young calves and sought veterinary help. The investigation and diagnosis revealed that old car batteries had been buried in a ditch in one of the pastures, and the calves had died from lead poisoning, says Glenn Selk, Oklahoma State University Extension beef specialist.
On further research, Dr. Selk found that very small amounts of lead could cause poisoning. Calves licking crankcase oil, grease from machinery, lead pipe plumbing and batteries can be in danger. While small calves represent the greatest percentage of lead poisoning cases because they are curious eaters, other cattle also can be affected. Junk or garbage in pastures can be a source of lead, including some crop sprays, putty, lead-based paints and painted surfaces, roofing materials, plumbing supplies, asphalt, lead shot, leaded gasoline and used oil filters.
Symptoms of lead poisoning are often similar to other diseases and require a veterinary diagnosis to accurately confirm. Clinical signs of poisoning normally precede death, but in many cases, animals are simply found down or dead in the pasture.
Observable signs vary from sub-clinical to very dramatic and take from just a few days to as many as 21 days to develop. Initial signs include depression, loss of appetite or occasionally diarrhea. The central nervous system may be affected and cause cattle to grind their teeth, bob their head, or twitch their eyes or ears. Some animals may circle, press their head or body against objects, or become uncoordinated and stagger. Muscle tremors, excitement, mania, blindness or convulsions may also be seen.
Treatment of lead poisoning can be costly and ineffective if not started early after ingestion of the lead. Successful treatments are usually started before the symptoms begin to appear and are often reserved for highly valuable animals.
Since treatment is costly, prevention is the key. Be aware of any old or new machinery in pastures. Avoid junk or debris that could be a source of lead. Above all, do not dispose of old car batteries in pastures where cattle have access to them. You can find more information from the Agriculture, Food, and Rural Development department in Alberta, Canada, in the paper “Lead Poisoning in Cattle” at www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex791?opendocument.