There has continued to be low usage of group four and five anthelmintics (wormers) among NI sheep farmers, reports from agricultural merchants and vets indicate.

Zolvix is the only group four (orange) wormer and is for the control of roundworms. It has almost no reported issues with resistance, and veterinary advice has been to use it as a quarantine drench for newly bought-in stock.

More recently, advice has also been to use it as a single-use wormer for lambs in mid/late season to maintain populations of worms on sheep farms that are not resistant to products in groups one, two and three.

Zolvix was previously only available from vets under prescription, but was re-classified in March 2017 for sale in agricultural merchants, to make it more accessible.

However, usage of Zolvix on NI sheep farms remains low, with price being the main factor putting farmers off incorporating it into wormer plans. For a 40kg liveweight lamb, a dose of Zolvix costs around £0.80 (including VAT).

Prices for wormers in other groups vary significantly. For a 40kg lamb, price can generally range from around £0.05 for a group one product such as Albex, to £0.26 for a group three product such as Cydectin.

The other product with no known resistance issues is Startect Dual Action. This is the only product in the fifth (purple) wormer group and is for the control of both roundworms and lungworms.

However, availability of Startect has been an issue for over a year, and suppliers indicate that it still cannot be sourced due to issues with the manufacturer.

Fluke

Meanwhile, livestock farmers in NI are being advised by local vets not to become complacent with liver fluke control this autumn.

Although conditions were dry this summer and not ideal for mud snails (the intermediate host for fluke), there is still a risk of liver fluke in livestock, particularly on farms where there have been heavy fluke burdens in the past.

Infection could still be picked up by livestock at this time of year, so a product affective against immature and mature fluke may be required.

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