The importance of washing the omasum for successful defaunation of sheep

Four different methods for defaunating were tested. Small Entodinia but som e times also other species of ciliates were found on the next day after def aunation when Aerosol OT was given in doses of 5 and 10 g/animal or 1-1.5 g /kg of rumen content. Emptying and washing the reticulorumen with a 0.9% Na Cl solution and subsequent freezing of the contents to -20 degrees C for 96 h resulted in absence of protozoa for a period of 10-14 days and this was followed by the re-establishment of a population of Eudiplodinium maggii, E ntodinium simplex and Dasytricha ruminantium. Emptying and washing of the r eticulo-rumen with warm (40 degrees C) water accompanied by heating of the contents to 70 degrees C and addition of 10 g of Aerosol OT or 5 g sodium l auryl sulphate (SDS) eliminated the ciliates from the rumen for a period of 7-40 days but re-establishment of small protozoa like Entodinium simplex a nd Entodinium caudatum was observed later. Emptying the reticulo-rumen and washing the omasum, reticulum and rumen wit h warm water followed by heating of the contents to 70 degrees C and the ad dition of Aerosol OT at a proportion of 1 g/kg digesta resulted in eliminat ion of all the species of ciliates from the reticulo-rumen of all defaunate d sheep for a period longer than 70 days.