Urea Poisoning

The main signs of urea poisoning are due to the alkaline-corrosive effects of the high NH₃ levels in the digestive tract and other tissues and the neuro-toxic effect on the brain. Signs of poisoning arise within 10-30 minutes of ingestion of toxic doses. There are three main types of poisoning: acute (severe), subacute (moderate) and chronic (mild).

Acute (severe)

Signs include salivation, severe abdominal colic, bloat, forced rapid breathing, muscle tremor, incoordination, bellowing, convulsions, violent struggling, weakness, recumbency, coma and death within 4 h of ingestion.

Subacute (moderate)

Signs include abdominal colic and milder nervous and circulatory signs.

Chronic (mild)

Signs include poor appetite, listlessness and lethargy.

Many thanks to Phil Rogers MRCVS

Footnote

The risk of urea poisoning is greatest when prilled urea is used.  Poisoning with liquid urea is least likely unless animals are able to drink the solution.