SCOPS said the recent publication of the first case of resistance to monepantel in the UK is a timely and important reminder to sheep farmers and their advisors.

Speaking on behalf of SCOPS, sheep consultant Lesley Stubbings said: “SCOPS welcomes this report because it not only highlights the need for sheep farmer to follow best practice advice, but also reveals the dangers of not integrating the newer wormer groups into on-farm control programmes before the other groups fail.

“It is SCOPS’ understanding that the farm concerned had a history of triple resistance to the 1-BZ (white), 2-LV (yellow) and 3-ML (clear) groups of anthelmintics, which meant they were relying almost exclusively on the newer monepantel wormer, the 4-AD (orange) group, for worm control.

“Coupled with animals being moved to low challenge pasture following treatment, which is highly selective for resistance, there was the risk of a ‘perfect storm’ in terms of the development of resistance. Other sheep farmers can avoid this situation by following SCOPS guidelines on the use of the 4-AD and 5-SI (purple) wormers.”

SCOPS has been advising that the group 4-AD and 5-SI wormers should be carefully incorporated into control programmes on sheep farms for the last eight years (when Zolvix was launched) as a quarantine drench and a mid/late season treatment for lambs. That advice was given, Ms Stubbings said, in order to avoid this sort of situation where the other three groups are no longer effective and the group 4AD is relied upon.