Influence of different grassland vegetation types on ruminal protozoa and ammonia in beef cattle

Abstract

Grassland vegetation types, which vary in concentration of nutrients and plant secondary compounds, may influence ruminal metabolism differently. Ruminal protozoa play a major role in ruminal protein degradation to ammonia and are involved in fibre digestion. Their role in, and response to, concentrate-based diets is well known. However, the effects of extensive grass-based diets on the composition of the protozoa population in the rumen are poorly understood. The present experiment investigated whether feeding grass or hay harvested from different vegetation types influences ruminal nitrogen metabolism and protozoa populations in beef heifers.