By Dr Rachel Gibney, District Veterinary Officer, Ballarat
Over the past year a significant number of properties in south west Victoria have had cattle die from lead poisoning.
The most common source of lead accessed by cattle comes from old car batteries that have been discarded beside sheds, in farm tips, or that have been burnt in bonfires.
Cattle have also been known to lick old paint that contains lead and consequently be poisoned.
Cattle find lead sweet and palatable, and they will selectively choose to eat it. If they find a lead battery, they often eat lumps of lead which will then sit in their stomach and act as an ongoing source of lead to the animal.
Lead toxicity in cattle is a concern for multiple reasons. Often the first indication that animals may have accessed lead is to find dead livestock. Lead also causes neurological signs such as blindness, depression and circling.
Low level poisoning may lead to gastrointestinal signs such as decreased appetite, colic and constipation, followed by diarrhoea.
It is important that cattle exposed to lead do not reach the human food chain, so restrictions are placed on the sale of such animals. Cattle may show no signs of being poisoned, but have a blood or tissue lead level that is of concern for food safety.
Blood testing can be performed to check if cattle have been exposed to lead.
Livestock other than cattle may also be affected if they ingest lead.
The best approach is to prevent exposure to lead.
Check to ensure that no old batteries are lying around on your property. If you suspect old paint may contain lead, make sure that livestock do not have access to the area.