The dosing of urea into the rumen of sheep caused acute intoxication characterised
by atony of the rumen, muscular spasms and sudden death due to circulatory
The toxicity of urea was found to depend on the activity of the ruminal flora,
as determined by the basic diet, and the presence of available carbohydrate.
Toxic symptoms after dosing urea were associated with the formation of
ammonia and a high pH of the ruminal contents. They could be prevented or
alleviated by the administration of acid.