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Worms present a significant production threat to sheep with infection and financial implications for farmers so the aim of any worm control strategy is to balance the exposure of susceptible animals to high levels of infestation on pasture against the overuse of anthelmintics.

For more information visit SCOPS


Nematodirus is a key disease which can affect young lambs in spring and summer, with cases now also reported in Autumn. Signs include the rapid onset of profuse watery diarrhoea, and the lambs quickly lose condition. If left untreated, lambs can die due to dehydration, with 5% of lambs dying within a few days if there is severe larval challenge.7

In addition, changing climatic conditions have meant that disease caused by this parasite has been a real challenge for sheep over the last few years, so it’s essential to be aware of the threat and know how best to manage it.

What is resistance?

Resistance is the ability of worms to survive the normal dose of a wormer and pass that ability on to its offspring. Worms can be resistant to one or more class of wormer at the same time.

Resistance develops gradually over time. It can be slowed down significantly if SCOPS guidelines on anthelmintic use are incorporated on the farm. However, once you have solid resistance to an anthelmintic class (i.e. obvious treatment failures) it cannot be reversed.

Resistance to wormers often results in productivity losses due to a low to moderate worm burden left behind after treatment. The sooner you act to manage this, the better the results.



Rycoben® SC

Tried and trusted by farmers, Rycoben is a broad spectrum white wormer used to treat liver fluke and worms in sheep, in particular used for Nematodirus in lambs; it also aids the prevention of cobalt and selenium deficiency.

Product Benefits

  • Ideal treatment for nematodirus
    • Rycoben is a Group 1-BZ white wormer – SCOPS advise using a white wormer because it highly effective against this parasite and is also suitable for young lambs.
  • The ONLY broad spectrum white drench licenced as an aid in the prevention of cobalt and selenium deficiency.
  • Contains therapeutic levels of cobalt and selenium to maintain lamb growth rates and aid in the prevention of production losses associated with trace element deficiencies.
  • Rycoben can be used as a targeted treatment for adult liver fluke in ewes in late spring or early summer to reduce the level of pasture contamination with fluke eggs – use at 1.5 times the dose rate for worms.
  • 3-day meat withdrawal – no other wormer has a shorter meat withdrawal – provides market flexibility and the opportunity to gain optimum market price.
Rycoben SC


Zolvix Oral Solution is a broad spectrum anthelmintic for the treatment and control of gastro-intestinal nematode infections and associated diseases in sheep, including lambs, hoggets, breeding rams and ewes. The first new class in 25 years, Zolvix is a 4-AD anthelmintic. Anthelmintic resistance to the three older classes of wormers is widespread1 – integrating Zolvix within worm control protocols helps slow the development of resistance5. Use annually to effectively kill worms and improve productivity within the flock2,3,4.

ZOLVIX – removes worms from sheep, even those that other wormers have left behind. Kills even resistant worms.

  • Wormer resistance now threatens most UK sheep farms1.
  • Use in every flock every year to boost productivity6,*and combat resistance before it’s too late. 

ZOLVIX is effective against all economically significant gut worms, both adult, immature and inhibited stages, including:

When to use:

  • Quarantine dose: to clean out incoming stock and protect your farm from resistant worms
  • Mid to late season break dose in lambs: to remove worm burdens and help maintain productivity
  • On farms with significant resistance: to manage the resistant worm population following advice from your vet