The metabolic changes which occur in sheep transferred to lush spring grass I. Changes in blood and rumen constituents

Abstract

1. Changes are observed in the concentrations of a wide range of substances found in blood and rumen contents when sheep are first turned out to lush spring grass.2. With some metabolites (e.g. rumen α-amino nitrogen, blood VFA) the increase is only temporary, and the animal (or its rumen microbial population) quickly adapts to the changed conditions. With other metabolites (e.g. rumen VFA) there is a sustained increase over a period of at least three weeks on grass.3. It is possible that the nature of the previous diet may determine the magnitude of the metabolic changes occurring.4. The overall nature of these changes should be taken into account in assessing the aetiology of the metabolic diseases occurring in ruminants under similar conditions.