Treating at housing provides opportunity to clear out parasite infection

Q Are there particular risks to be vigilant against this autumn? How do farmers spot the risks and what can they do?

A There has been plenty of wet weather hitting the UK this year and the National Animal Disease Information Service fluke forecasting tool has therefore predicted fluke will be an issue for many farms this autumn.

Fluke can affect cattle of any age and should be considered in cases of scour, condition loss or drop in production after or during grazing.

Fluke treatments can be a challenge in lactating dairy cattle due to withdrawal periods, so it is best to consult your vet for testing and product selection.

We have also seen several lungworm outbreaks recently, which is an important consideration whenever cattle are seen coughing at grass.

It is important with cases such as these to treat all animals in the group, not just those animals which are coughing.

Q Should all cattle be treated for worms, lungworm and fluke at housing?

A In short, no. Targeted treatment is a good way to prevent resistance and save money.

Treating only the animals which have a high worm burden or which are most vulnerable will ensure a population of vulnerable worms is kept on pasture.

It is important to protect animals and pasture from entirely resistant parasite populations in the future, known as maintaining a refugia.

The best way to achieve targeted treatment is by treating groups or individual animals that return a high faecal egg count for worms, a high larval count for lungworm or a high coproantigen for fluke.

Q When should treatments be carried out in relation to housing?

A It is sensible to treat all animals being housed after their first grazing season for gut worms.

For example, the lifecycle of Ostertagia worms means large numbers of the parasite can encyst within the abomasum and emerge in volume in January to cause winter scours.

Treating at housing can prevent those parasites from over-wintering and going on to cause problems in young animals through winter and into spring.

Q How important is it to make sure dosage is correct?

A We know underdosing is one of the biggest reasons for treatment failures and for increasing resistance.

To avoid underdosing, animals of similar weight should be grouped and dosed according to the heaviest animal.

It is important to check the correct volume is being dispensed by the worming gun and that it is in working order beforehand.

Q With increasing reports of resistance to certain wormers, what is the best way of checking a treatment has worked? And what can farmers do if resistance is found?

A Gut worm resistance is an increasing concern for the sheep industry and although resistance has been noted in cattle, it is not as widespread yet.

It is increasingly evident that we are seeing resistance to the limited selection of drugs on offer in livestock and this resistance will progress in the future.

Resistance to drugs is not a reversible process so it is crucial they are used responsibly.

For example, triclabendazole resistance is an issue for both cattle and sheep and is a big problem as this is the only product that targets immature fluke.

A lack of response to treatment can be measured using reduction testing. This quantifies the effect of the wormer by measuring the reduction in worm eggs post treatment.

It compares this reduction to what is expected of non-resistant, vulnerable worm populations.

It is a good monitoring tool if unexplained treatment failures with wormers and flukicides are seen.