An autopsy was carried out on an aged mule and the gastro-intestinal nematodes recovered in a modified Baermann apparatus in a waterbath. Ingesta were initially placed on fibreglass gauze (apertures 1,5 X 1,1 mm) and the filtrate subsequently poured on to a double gauze platform in traps. The upper platform had nylon grit gauze with an aperture of 700 micron, while the lower platform had gauze with an aperture of 500 micron. As many as 56,7% Probstmayria vivipara and 75,2% of the other nematodes migrated through all three layers of gauze into the filtrate, which constituted less than 5% of the total ingesta. Although 12,9% of the strongyles were washed off the caeco-colonic wall, none were recovered when this gut wall was subsequently digested.