Key facts
- Lead poisoning is a common toxicological problem in cattle herds in Western Canada.
- Discarded batteries in pastures are a frequent source of lead exposure.
- Symptoms include blindness, diarrhea, and inco-ordination; sudden death can occur.
- A 10-year study (2014-2024) identified 233 cattle herds with confirmed lead poisoning.
- Calves under four months of age are most commonly affected.
- Animals that survive may still have high lead levels, posing a food safety risk.
Lead poisoning is identified as a significant and common toxicological issue affecting cattle herds in Western Canada, with potential devastating consequences for producers due to animal sickness and death. The primary cause is often the consumption of lead from discarded batteries found in pastures, particularly during the early grazing season. Symptoms can include neurological signs such as blindness and inco-ordination, as well as diarrhea, and in severe cases, rapid death. A study published in the Canadian Veterinary Journal, covering cases from 2014 to 2024, documented 233 cattle herds experiencing confirmed lead poisoning, with samples from 352 cattle showing high lead levels. Outbreaks were most frequent in May, June, and July, and recent pasture changes were frequently noted in case histories. Calves under four months of age were most commonly affected, likely due to their curiosity and higher absorption rates. A critical concern highlighted is the potential food safety risk, as animals that survive or do not show clinical signs may still retain elevated lead levels in their tissues, posing a danger if they enter the food chain. The study emphasizes the importance of testing blood lead levels in entire groups of cattle if lead poisoning is diagnosed in an individual, as the half-life of lead in the blood can be highly variable. Veterinarians are advised to submit tissues for post-mortem examination or take blood samples from live animals for testing. In Alberta, lead poisoning is a provincially reportable disease.