Specificity of Rumen Ciliate Protozoa in Cattle and Sheep*

SYNOPSIS. Six protozoa‐free sheep, 3 fed alfalfa hay and 3 fed a concentrate diet, were inoculated with rumen contents from a steer fed the same alfalfa hay. All 24 species of protozoa in the inoculum became established in the sheep fed alfalfa hay, while only 9 species established in the sheep fed concentrate. Percentage species composition in the alfalfa‐fed sheep was fairly similar to that of the inoculum. Rumen volumes of the alfalfa hay‐fed sheep were significantly higher than those of the concentrate‐fed sheep; however, fluid turnover rates were similar. Total protozoan numbers per ml of rumen contents were significantly higher in the concentrate‐fed sheep, but after adjustment for rumen volume, there was no significant difference in the total number of protozoa in the rumen.