TEXAS VET NEWS By Dr. Bob Judd, DVM and the Texas Farm Bureau Texas Farm Bureau Radio Network

One of the most common toxicants in cattle is lead poisoning.  Lead has been recognized as toxic for over a thousand years and still causes poisoning in people, wildlife, and domestic animals.  Dr. M.F. Raisbeck indicates common sources of lead include old paint, plumbing, linoleum and sheathing, shotgun shell shot, solder, and electric storage batteries.  The most common source of lead poisoning was motor oil that was used in engines that used leaded gasoline.  With the decrease in leaded gas, this source of lead poisoning has decreased. 

Lead particles tend to settle and can be retained in the bovine GI tract for a longer period of time that increases toxicity.  Chronic exposure to lead usually causes behavioral disorders.  Lead is also excreted in the milk and could cause public health problems.  Total elimination of a single dose of lead in cattle can take 1 to 2 months.  Acute exposures are the most common in cattle with the common signs being muscle twitches, hyperexcitability, blindness, and seizures.  Gastrointestinal signs can also develop such as abdominal pain, inappetence, and diarrhea.  Chemical analysis of blood, liver, and kidney can confirm the diagnosis.  Treatment of any poisoning begins with identifying and removing the toxin.  Thiamine has been shown to decrease some of the effects of lead. The best treatment is to chelate the lead with calcium sodium EDTA.  This product is difficult to find but can be compounded. 

Lead poisoning should be considered in any livestock showing gastrointestinal or neurological disease.  In general, most poisoning cases involve multiple animals in a herd.  For this reason, it is important to have your veterinarian do a necropsy on any livestock that die of an unknown cause.  

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Date Published: 2/18/2005 10:36:00 AM