Fifteen Bunaji calves (Bos indicus) averaging 105±12.5 Kg liveweight and approximately nine months of age with natural helminth infection were distributed into three treatment groups of five animals each. Animals were either treated orally with aqueous extract of Vernonia amygdalina at a dose concentration of 1.1g/Kg body weight, a conventional anthelmintic or left untreated. V. amygdalina treatment produced 59.5% reduction in eggs per gram (EPG) of faeces which was significantly different (P<0.001) from the untreated control (-17.24%), whereas levamisol hydrochloride treatment produced 100% reduction in EPG. A total of six genera of helminths were recovered from the gastrointestinal tracts and liver of experimental animals. These were Haemonchus contortus, Trichostrongylus spp, Bunostomum spp, Oesophagostomum spp, Fasciola spp and Dicrocoelium spp. There was significant difference (P<0.001) in worm load between the different treatment groups. Except for Haemonchus spp, animals in the untreated group had significantly (P<0.001) higher worm load for all the genera of helminth recovered than those of the V. amygdalina treated group, indicating that V. amygdalina had no effect on Haemonchus contortus.

Key words: Anthelmintic, Calves, Helminth, Vernonia amygdalina