Nitrogen dioxide (silo gas) poisoning in pigs

Area of Science:

• Agricultural Safety
• Veterinary Toxicology
• Environmental Health

Background:

• Silo gases are a known hazard to livestock in agricultural settings.
• Early ensiling stages can produce toxic gases, posing risks to animal health.
• Proximity of livestock housing to silos increases exposure potential.

Purpose of the Study:

• To investigate a case of livestock mortality linked to silo gas exposure.
• To identify the specific toxic gases involved and their source.
• To discuss the production and toxicological effects of silo gases.

Main Methods:

• Post mortem examination of deceased pigs.
• Identification of toxic gases present in the affected animal housing.
• Analysis of the silo and adjoining structures for gas accumulation and leakage pathways.

Main Results:

• Five fattening pigs died due to extensive lung damage and methaemoglobinaemia.
• A toxic gas mixture of nitrogen dioxide and dinitrogen tetroxide was identified at floor level.
• The gases accumulated in a slurry channel and leaked into the piggery, affecting other pigs.

Conclusions:

• Nitrogen dioxide and dinitrogen tetroxide produced during ensiling can be lethal to livestock.
• Accumulation in adjacent structures like slurry channels can facilitate dangerous leaks.
• Effective ventilation and monitoring are crucial for preventing silo gas-related incidents in animal husbandry.