Diurnal changes and effect of ration on concentrations of the rumen ciliate Charon ventriculi.

Charon ventriculi comprised over 30% of the total protozoa observed in rumen contents of a Flamenga cow fed Rhodes grass hay (Chloris gayana). Both percentage of composition and concentration decreased markedly when concentrate was added to the ration or the animal was fed in pasture. Although C. ventriculi is classified as a holotrich, concentrations of this species in the rumen appear to follow a diurnal cycle more closely related to be entodiniomorph protozoa.