Observations on the removal of Oesophagostomum columbianum Curtice from sheep grazing on green oats and on pastures.

Abstract

Field trials in 1951 and 1952 confirmed previous observations on the evacuation of adult Oesophagostomum columbianum Curtice from sheep which graze continuously on green oats. Ingestion of phalaris-subterranean clover or red clover pasture also resulted in the evacuation of some O. columbianum but was much less effective in this regard. Evacuation of O. columbianum from sheep on green oats was not complete and was associated with softening, and lowering of the pH, of the faeces. The phenomenon occurred both with and without a considerable increase in liveweight. Some of the factors associated with oat-grazing which may influence removal of O. columbianum are discussed.