1. It has been shown that the administration of alkali (sodium carbonate or
sodium hydroxide) into the rumen causes ruminal paresis if the pH exceeds
2. Ruminal paresis can also be caused by the intravenous injection of alkali
(sodium hydroxide or ammonia) indicating that the paresis associated with alkalinity
of the ruminal ingesta is of central origin.
3. No corresponding effect could be demonstrated following the dosing or
injection of acid.
4. The paretic ruminal musculature is still capable of normal contraction as
shown by the reaction to feeding and the response to carbamylcholine.
5. The possible significance of alkalinity of the ingesta in the aetiology of
ruminal stasis is discussed.