A small scale survey of ivermectin resistance in sheep nematodes using the faecal egg count reduction test on samples collected from Scottish sheep

D J Bartley, A A Donnan, E Jackson, N Sargison, G B B Mitchell, F Jackson

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Thirty-eight sheep flocks, predominantly from the south/central Scotland, were examined using a faecal egg count reduction test (FECRT) for the presence of ivermectin (IVM) resistant nematodes. Efficacies of less than 95%. 14-17 days post-treatment, were identified in 6 of 17 naturally grazing flocks where pre-treatment faecal egg counts were in excess of 150 eggs per gram. Efficacies on these IVM resistant farms ranged from 66 to 92%. One other suspected cases of IVM resistance was also identified in returned material. The larvae detected in post-treatment coprocultures from resistant flocks were from the genera Teladorsagia (4 from 6) and Trichostrongylus (2 from 6). (C) 2005 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)112-118
Number of pages7
JournalVeterinary Parasitology
Issue number1-2
Publication statusPublished - 15 Apr 2006

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