An open letter to all sheep farmers
As the grazing season progresses, we would like to remind prescribers of the need to encourage all sheep farms to integrate the two newer wormer groups (4-AD orange (Zolvix) and 5-SI purple (Startect)) into their worm control plans, as advised by the Sustainable Control of Parasites in Sheep (SCOPS) group.
Recent market research has shown that the vast majority of sheep farmers are aware of the threat of anthelminthic resistance (AR).
However, despite published studies showing the presence of AR on 98% of farms (WAARD study), 85% of farmers still believe that the wormers they use on their own farms are working as well as they always have.
This is because less than a quarter of those questioned use any method (e.g.
worm egg counts) to monitor treatment efficacy; and neither are the majority monitoring growth rates in their lambs, which would give them early warning of resistance developing.
Because most farmers can’t see the reduction in lamb performance, they are often reluctant to adopt new management practices (e.g.
routine worm egg counts) that would make this invisible problem visible.
Swapping a dose of an older grp 1 BZ, grp 2 LV or grp 3 ML wormer to a grp 4 AD or grp 5 SI in the latter part of the grazing season will give a visible improvement in performance in most cases as worms left by previous treatments are removed.
The two newer groups used in the latter part of the season can help lambs to reach their growth potential by removing the build-up of worms that have survived previous treatments.
In addition, this treatment helps slow the development of resistance to the older three groups of wormers, if they are deployed before the older wormer groups become ineffective.
This is why action now is so important.
The aim is for one of the two newer groups to be used on all sheep farms at two points in their worm control plan.
Firstly, as part of their quarantine treatments for all incoming sheep, and secondly as a one-off treatment for lambs, in the latter part of the grazing season.
An effective farm protection (quarantine) treatment is essential to prevent otherwise healthy sheep bringing resistant worms onto the farm.
For full details go to www.scops.org.uk/internal-parasites/worms/quarantine-treatments/.
To gain the maximum benefit from the treatment for lambs, it is important that the treatment is given in the latter part of the grazing season (as a mid-late season break dose), when a treatment is deemed necessary (following a significant worm egg count), and all lambs remaining on the farm should be treated.
NOTE: To avoid the risk of selecting for resistance to the newer group 4-AD & 5-SI wormers, it is very important not to “dose and move” lambs to “cleaner” grazing straight away.
To avoid this risk simply drench the lambs and return them to the same fields for four or five days before moving them.
For more details on mid-late season break dose go to www.scops.org.uk/news/5221/sheep-farmers-encouraged-to-use-newerwormers-as-a-mid-season-lamb-dose-this-summer/.
This is a first step that all sheep farms can easily take to make the otherwise invisible problem of AR more visible, and help them take the next step towards more sustainable worm control and more efficient, profitable sheep farming.
