Resistance to the wormer monepantel (Zolvix/orange) has been detected in sheep for the first time. Monepantel is one of the newer generations of wormers, so resistance to this class is a significant and worrying development.
In order to prevent further resistance developing a prolonging the lifespan of other classes of wormer it is important to follow best practice as set out by SCOPS. This includes introducing the orange and purple classes of wormer before the other classes of wormer have stopped working, rather than leaving them as a last resort. They should be alternated and used as a quarantine dose and/or a a 'one-off' annual drench for lambs.
Worm egg counts can also play a vital part in prolonging the life of all classes of wormer. By understanding the exact worms that are affecting stock it is possible to chose a wormer that targets them specifically, rather than guessing and potentially using an unsuitable wormer.
More information can be found in this article.
Agrix Nutrition can help with worm counts in sheep, cattle and horses, along with advice on all worming matters. Contact us for more information.