Diurnal Variation in the Numbers of Rumen Ciliate Protozoa in Cattle

Abstract

The total numbers of ciliate protozoa in the contents of the rumen and reticulum were calculated from counts made on representative samples. The samples were obtained when the entire contents were removed through the rumen fistula, weighed, mixed, sampled, and returned to the animal. Diurnal variation was found in the populations of both oligotrichs and holotrichs. The fluctuations in total numbers of Isotricha appeared to be related to the diet and dietary regime of the host. When the host was fed chaffed red clover hay for two hours daily a marked rise in isotrich numbers occurred during feeding. When the host was fed fresh red clover for two two-hours periods each day a fall in isotrich numbers occurred. Destruction of the organisms by bursting may have caused this decrease. It is suggested that, since the cell contents thus liberated can have strong foam-stabilising properties, bursting of isotrichs could contribute to the occurrence of bloat. © 1965, Taylor & Francis Group, LLC. All rights reserved.