Detection of anthelmintic resistant nematodes in sheep in southern England by a faecal egg count reduction test
Grimshaw, W.T.; Hunt, K.R.; Hong, C.; Coles, G.C.
Veterinary Record 135(16): 372-374
1994
ISSN/ISBN: 0042-4900 PMID: 7831741 Document Number: 432703
On 5 farms identified by in vitro tests to have benzimidazole resistance, and on one farm with apparent anthelmintic failure, faecal egg count reduction tests were performed using benzimidazoles, levamisole and ivermectin. With benzimidazoles efficacy was less than 70% on all farms, confirming the validity of the in vitro tests to detect benzimidazole resistance. On 2 farms levamisole had an efficacy of less than 90% but laboratory tests failed to detect levamisole resistance. Ivermectin reduced egg counts by 100% on all farms.