UK Gets First Dual Active Worming Product

At the end of March, the first worming product for sheep to contain two broad spectrum active compounds (derquantel the new novel 5-SI group + abamectin a 3-ML group), was launched on to the UK market (Startect™ available through your Vet). This is a very  important addition to our armoury of products available to deal with worm burdens and if used correctly will help us to delay the impact of anthelmintic resistance (AR) on sheep performance.

Firstly, we need to distinguish this product from our existing ‘combination products’ which contain two actives addressing different parasite types, for example fluke and roundworms or roundworms and tapeworms.  This is why the product is known as a ‘dual active’ so you  can make the distinction between the types of product, minimising any confusion. 

Secondly, dual active wormers have the potential to delay the development of resistance to the component chemical groups. This is maximised when certain conditions are met in terms of the activity, duration and modes of action of the actives, all of which this product meets. However, there are two very important SCOPS principles that are also vital pre-requisites to ensure you gain maximum benefits from the resistance-delaying potential of a dual-active These are:

1. You need to  know the resistance (AR) status on your  farm, in particular to the 3-ML group because pre-existing resistance must be low to if you are to maximise the potential  to delay further resistance. Recent surveys confirm that there are a growing number of farms with detectable levels of AR to the 3-ML group. If it is present on your farm then you need to proceed with care, in line with current SCOPS advice. Of course SCOPS encourages sheep farmers to carry out drench tests on a routine basis for all groups to make sure an effective anthelmintic is always used. 
2. Ensure that you leave a proportion of the worm population unexposed to the anthelmintic (in refugia ). This is quite a difficult concept to grasp but it is becoming very clear that of all the SCOPS recommendations, this is the one we have to work at most because of it’s  huge impact on the speed that resistance (AR) develops. In essence it means you need to think carefully about the key issues such as how to handle low contamination pastures (not doing a straight ‘drench and move’ for example), integrating partial or delayed move after treatment and not unnecessarily treating adults.