Choosing a Product

Choosing the right product and getting the most from it are key factors, not only in the fight against anthelmintic resistance but also in ensuring optimum sheep performance at least cost.

In practice, however, this is easier said than done. Working your way through the wide range of products available, the chemical groups, withdrawal periods etc. is difficult and time consuming. Use the SCOPS ‘Know Your Anthelmintics Groups’ Guide for accurate, easy-to-use information on the products available in the various chemical groups and the parasites they control.

Also refer to updated SCOPS advice specific to the use of moxidectin 2% - more below.

SCOPS wants you to get the most out of an anthelmintic every time you use it by helping you to:-

  • Choose the right product. Targeting the parasite(s) correctly means better results and reduces the risk you will need to treat again.
  • Source a narrow spectrum product where appropriate, which will reduce selection for resistance to the broad spectrum groups.
  • Use combination products only when they are necessary.
  • Administer anthelmintics effectively and handle and store them correctly.
  • Not mix anthelmintics with any other product prior to administration.
  • Check the product has been effective by carrying out a simple drench test. Resistance sneaks up on you and this will give you early warning. It will also make sure you are using an effective product that gives good worm control.

Remember, it is not too late to slow the development of anthelmintic resistance down on most farms. Act now and safeguard the future of worm control on your farm.

Particular concerns around moxidectin, specifically the 2% injectable formulation, have prompted additional advice for prescribers on this product in order to preserve it as both an anthelmintic for worms and a treatment for sheep scab. Concerns have arisen as a result of reports of potential over-use, in particular as a treatment for ewes at lambing, coupled with an increase in prevalence of moxidectin resistance in the UK. Download detailed information at the bottom of this page, and please note the following SCOPS principles specific to moxidectin 2%:-

  • Year on year use of moxidectin in ewes around lambing is unadvisable in any flock. Simply rotating with other wormer groups within a season is not enough.
  • If ewes are treated with moxidectin, some must be left untreated. It is essential to leave at least 1 in 10 of the ewes untreated (and preferably more than that) and these need to be spread between different grazing mobs. It is not enough to simply leave singles as they may be grazed in separate fields to twins. Use body condition as a guide with the fittest ewes left untreated.
  • Moxidectin 2% should not be used more than once in any flock in any one year. In practice this means that if moxidectin 2% is used in ewes at lambing then moxidectin should not be used again in that flock in the same season.
  • Where moxidectin 2% has been used in ewes to suppress the spring rise then it should not be used to treat sheep scab (or vice versa). An OP plunge dip is an appropriate alternative to treat scab.
  • Check the dose rate and administration method. Underdosing remains a major risk factor in the development of anthelmintic resistance. Sheep farmers should know the weight of their sheep and dose to the heaviest (if a wide range of weights is expected, batch and dose accordingly). The correct technique for administration and maintenance / calibration of equipment is also vital.

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