In field trials in 1983-84, Hereford weaner steers were given no anthelmintic treatment or were treated with morantel slow release bolus, pour-on levamisole or albendazole orally. Nematode egg counts in faeces were generally <50/g, indicating low numbers of adult nematodes. Treatment significantly affected mean faecal egg count, those for controls and morantel being 16 and 10/g above the overall mean (47/g) and levamisole and albendazole 6 and 12/g below the mean. There were no significant differences between treatments in numbers of larvae on pasture. At the end of both years most nematodes were early 4th stage larvae of O. ostertagi. There were no significant differences in nematode counts or...