Chandrasekharan, KSukumara Pillai, GKAU2020-11-192020-11-191980170081https://krishikosh.egranth.ac.in/handle/1/5810155241MVScThe non – descript and cross bred Calves of Kerala were infected with eight species of gastro – intestinal nematodes viz. Strongyloides papillosus, Neoascaris vitutorum, Cooperia sp., Haemonchus contortus, Bunostomum phlebotomum, Oesophagostomum radiatum, Trichostrongylus colubriformis, and Trichuris globulosa and of which Strongyloides papillosus was the commonest. Incidence of namatodes was more in cross bred calves (64.8 per cent) as compared to non – desctipt calves (51.52 per cent). Out of the cross bred calves, Jersey cross bred calves were found to more susceptible to nematodiasis. Nematodiasis was observed more during the rainy season of the State (June to August). Morphological features of adult worms and infective larvae were redescribed in detail. Strongyloides papillosus produced catarrhal enteritis and frequent diarrhoea in naturally infected cross bred calves. Thiophanate at 100 mg per kg body weight, Mebendazole at 15 mg per kg body weight, Levamisole at 15 mg per kg body weight., Thiabendazole at 100 mg per kg body weight, Tetramisole hydrochloride at 20 mg per kg body weight, Morantel tartrate at 15 mg per kg body weight and parbendazole at 45 mg per kg body weight exerted 100 per cent efficacy against Strongyloides papillosus, whereas, Fenbendazole at 5 mg per kg body weight showed only 83 to 100 per cent efficacy against Strongyloides papillosus, 78 to 100 per cent against ascariasis, 85 to 100 per cent against Strongylosis and 50 to 100 per cent against Trichuriasis.EnglishThesis