Studies on the alimentary tract of the merino sheep in South Africa. XXII. The effect of the pH of the ruminal contents on ruminal motility

Abstract

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 approximately 7•5. 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.