Rajeev Ranjan Kumar

Detection of benzimidazole resistance in gastrointestinal nematodes of sheep and goats of sub-Himalyan region of northern India using different tests.

The present investigation was planned with the objective of studying the status of benzimidazole (BZ) resistance in gastrointestinal nematodes (GIN) of sheep and goats of different agro-climatic zones of sub-Himalyan region of northern India using in vivo faecal egg count reduction test (FECRT) and in vitro tests namely egg hatch assay (EHA) and larval development assay (LDA). Out of fourteen flocks, FECRT detected resistance in eight flocks (two sheep flocks and six goat flocks) with FECR% ranging from 54.95 to 90.86. Pre treatment coproculture contained predominantly Haemonchus contortus, followed by Trichostrongylus spp., Oesophagostomum and Strongyloides, while post treatment coproculture results showed that only H. contortus survived fenbendazole (FBZ) (in FECRT) or thiabendazole (TBZ) (in LDA) treatment except in three flocks of Tarai region {one sheep flock (Us1), and two goat flocks (Ug1 and Ug5)} where BZ resistant Trichostrongylus were also detected. The GIN of those eight farms which were found resistant by FECRT were also detected resistant by EHA. Arithmetic mean and range of ED50 value of susceptible group was found to be 0.059 μg/ml and 0.037-0.096 μg/ml, respectively, and the same for the resistant group were found to be 0.119 μg/ml and 0.101-0.147 μg/ml, respectively. With LDA, the arithmetic mean and range of LC50 value of susceptible group was found 0.0030 μg/ml and 0.001-0.005 μg/ml, respectively, and those of resistant group was found 0.0105 μg/ml and 0.009-0.012 μg/ml, respectively. The values of Spearman rank correlation coefficient indicated that negative correlation was found between FECR% and ED50 and between FECR% and LC50 while positive correlation existed between ED50 and LC50 value and the p-values indicated that these correlations were statistically highly significant. In the present study, FECRT and EHA gave comparable results with regard to detection of BZ resistance in GIN in sheep and goats. Although with LDA, the threshold LC50 value could not be established as for EHA but LDA indicated the presence of low level of resistance in GIN of both sheep and goats. For effective worm control, regular monitoring for anthelmintic resistance is important to know the status of anthelmintic efficacy in a particular agro-climatic zone. The baseline information thus generated will enable timely management of benzimidazoles resistance in GIN.

Impact of treatment of gastrointestinal nemathelminths on body weight of sheep and goats.

Gastrointestinal nemathelminths affect productive as well as reproductive performance of a wide range of ruminants. To assess the impact of anthelmintic treatment on gain in body weight (b. wt.)xa0of sheep and goat, a study was conducted using two different flocks of sheep and goats each maintained in semi intensive system. Infected animals in both the flocks were divided into three groups each. Group I and II in each flock were treated with levamisole (@7.5xa0mg/kg b. wt. subcutaneously) and fenbendazole (@5xa0mg/kg b. wt. orally), respectively. Animals of group III were kept as untreated control. Individual b. wt.xa0and faecal egg count were recorded up to 42nd day post treatment. Results showed 100xa0% reduction in faecal egg count of sheep on day 7 after treatment with levamisole and on day 10 after treatment with fenbendazole. In goats, the reduction in faecal egg count was 82.60xa0% after treatment with levamisole and 78.87xa0% after treatment with fenbendazole on day 14 post treatment. The study also revealed mean increase of 29.57 and 22.67xa0% in b. wt.xa0of sheep treated with levamisole and fenbendazole respectively 42nd day post treatment whereas mean b. wt.xa0of infected untreated control groups decreased by 7.14xa0%. Similarly, there was an increase of 10.71 and 14.47xa0% in mean b. wt.xa0of goats 42nd day post treatment with levamisole and fenbendazole, respectively whereas mean b. wt.xa0of untreated control group decreased by 15.38xa0%. More weight gain was recorded in sheep as compare to goats after treatment as compared to the untreated control group, which may be due to some drug resistance in goat and required clarification by further studies in these ecological zones of Udham Singh Nagar.