Lead
It is common cause of poisoning in cattle. Lead poisoning in other species is limited by reduced accessibility, more selective eating habits, or lower susceptibility. In cattle, many cases are associated with seeding and harvesting activities when used oil and battery disposal from machinery is handled improperly. Other sources of lead include paint, linoleum, grease, lead weights, lead shot, and contaminated foliage growing near smelters or along roadsides. Lead poisoning is also encountered in urban environments, and old houses painted with lead-based paint has been associated with lead poisoning in small animals. After consumption, small portion of lead is absorbed and it is excreted through bile, urine and milk. It causes encephalopathy, gastroenteritis and degeneration of peripheral nerves.
In acute poisoning, animals reveal muscle tremors, champing of jaw, salivation, blindness, muscular twitching, convulsion, hyperasthesia and death. In chronic cases, head pressing, long standing posture, circling, excitement, blindness and mania, grinding of teeth, ruminal stasis, gastroenteritis and abdominal pain are noticed. Animals die as a result of respiratory failure during convulsions. It is diagnosed by clinical signs or by measuring the level of lead in blood and also detected indirectly by measuring delta aminolevulinic acid which decreases in blood in lead toxicity.
Lead levels in various tissues may be useful to evaluate excessive accumulation and to reflect the level or duration of exposure, severity, and prognosis and the success of treatment. Concentrations of lead in the blood at 0.35 ppm, liver at 10 ppm, or kidney cortex at 10 ppm are consistent with a diagnosis of lead poisoning in most species.
The animals can be treated with calcium versenate (calcium EDTA) given @ 100-200 mg/kg body weight intravenously thrice daily for 3-4 days. Thiamine given @ 2 mg/kg body weight subcutaneously also helps in its treatment. Simultaneous use of Ca EDTA and vitamin B has synergistic effect. Use of 400-600 g magnesium sulphate orally precipitates lead.