VETERINARY surgeons have been reminded of the importance of quarantine dosing for sheep because of the inherent risk of introducing new parasites and diseases onto farm. Anthelmintic-resistant worms and sheep scab are considered to be two of the most likely problems to be imported into existing flocks with the arrival of new stock, according to SCOPS (Sustainable Control of Parasites in Sheep). Resistance to wormers is of growing concern to the sheep industry in the UK and across the world. Roundworms have been found on some farms that are resistant to three of the four classes of drench. The latest class, known as the 4AD or orange drench group, has no worm populations that are resistant to it, and as such makes an excellent first choice when quarantine dosing. Fiona Anderson, a veterinary adviser with Novartis Animal Health, said quarantine dosing was one of the simplest health messages being put forward, but not always one that was being followed.
Don’t buy in trouble…
“When new stock is bought in there is no information available about the resistance status of the farm they have come from. The message vets need to pass on to farmers is a simple one: don’t buy in trouble,” she said. “I think some farmers are slow to take up quarantine dosing because the problem is not immediately visible. However, even in the short term, if they are importing resistant worms onto their farms they can see an immediate loss in productivity in early season lambs. This fall in productivity will become long term until the problem is dealt with.” She said it was important that farmers were advised by their vets to follow SCOPS guidelines when bringing in new stock.
“Because there is no resistance to it, the orange drench Zolvix is the key to quarantine dosing. I would also recommend an ML injection to cover against scab where this is a risk,” she said. SCOPS chairman, Peter Baber, believes that with breeding stock, quarantine dosing is a “no brainer”, and if store lambs are bought in, it is equally important although withdrawal periods can be an issue.
Quite horrendous
“From a worm perspective, monepantel is the preferred treatment at the moment. Also, since scab is a constant threat these days, and the consequence of introducing scab is quite horrendous, I would advocate that people treat incoming sheep with monepantel and moxidectin 1% by injection to cover both risks,” he said. “I think there is a growing awareness of the issues. Quarantine dosing is a sound principle and anything we can do to encourage it must be welcomed. It’s a common sense method of going some way to protecting the future health of our flocks.” “Novartis has brought out a smaller 500ml pack size for Zolvix which has been very helpful for farmers who take on smaller quantities of new stock. It obviously has implications in terms of uptake,” said Mr Baber, who farms 1,050 ewes on 400 acres in Devon. SCOPS recommends that all sheep brought onto farm are yarded for between 24 and 48 hours on their arrival. They should then be drenched with the 4-AD wormer onepantel,
followed by moxidectin. If scab is a risk then the 1% injectable form of moxidectin should be used. Finally, sheep should be turned out to pasture that has carried sheep in the season, and
kept isolated for three weeks, preferably longer. Lesley tubbings, of SCOPS, said: “The consequences of not quarantining
could be threefold: farmers could be buying in anthelmintic resistance. They could be buying in the Barber’s Pole worm, Haemonchus contortus, and if that gets loose in a flock that hasn’t had experience of it, this can be devastating. Bringing in sheep scab is potentially very damaging.” “I would urge vets to advise farmers that they are at their most vulnerable when they take new stock onto farm. Why take the risk? An animal might look healthy on the outside, but you don’t know what’s on the inside. These animals are coming from different farms, they will have different parasites and worms of varying resistance to one
or more available anthelmintic groups. “Quarantining does bear a cost, but it is a very small price to pay compared to the cost of the damage that infection and parasites can do,” she said. Since its launch last year, monepantel has played an important role in treating intestinal roundworms, including those that have resistance to older classes of wormer. Simon Harris, Zolvix brand manager at Novartis Animal Health, said: “Zolvix has received very positive feedback from vets and farmers throughout the UK. It plays a key role in quarantine procedures to prevent resistant worms being brought onto farm and helping economic performance. The product has a meat withhold period of just seven days which allows flexibility when marketing lambs, and it can be used in pregnant or lactating ewes.” “We’ve made it as easy as possible to administer with the Optiline drencher which ensures an accurate and safe delivery of doses,” he said. n For details on SCOPS guidelines, see www.nationalsheep.org.uk.
