Terbufos poisoning in a dairy herd

Area of Science:

• Veterinary Toxicology
• Animal Science
• Environmental Health

Background:

• Organophosphates, such as terbufos, are widely used pesticides with known toxicity.
• Accidental exposure can lead to severe health consequences in livestock.
• Understanding dose-dependent effects and treatment efficacy is crucial for animal welfare.

Purpose of the Study:

• To document an outbreak of accidental terbufos poisoning in Holstein cattle.
• To investigate the clinical signs, treatment responses, and diagnostic findings.
• To differentiate effects based on exposure levels.

Main Methods:

• Clinical observation of affected Holstein cattle (heifers and milking cows).
• Administration of treatments including atropine sulfate, pralidoxime chloride, and activated carbon.
• Post-mortem confirmation through tissue and feed analysis for terbufos.
• Measurement of whole blood cholinesterase activity.

Main Results:

• Heifers ingesting a high dose (7.5 mg/kg) of terbufos exhibited severe respiratory distress and died within 12 hours, unresponsive to atropine sulfate.
• Cows exposed to diluted feed showed typical organophosphate poisoning signs and responded to atropine sulfate.
• Late administration of pralidoxime chloride and activated carbon (48 hours post-ingestion) did not improve outcomes in severely affected cows.

Conclusions:

• Terbufos poisoning in cattle is dose-dependent, with high acute doses leading to rapid mortality.
• Atropine sulfate is effective for milder organophosphate poisoning, but late-stage or severe cases may not respond to supportive treatments.
• Accurate diagnosis relies on clinical signs, exposure history, and laboratory confirmation of terbufos and cholinesterase inhibition.