Agriland Media is delighted to collaborate with Elanco Animal Health to bring you part three of the Flock Forwards, not Backwards Series.
Head of Sheep Knowledge Transfer at Teagasc, Michael Gottstein, shared his wisdom in the final episode of the Flock Forwards, not Backwards series.
With every sheep farmer in a longstanding battle against gut worms, it is imperative they are managed effectively.
Wormer resistance in Ireland – where are we at?
Gottstein discusses levels of resistance across the country, referring to a number of studies carried out over the past 20 years.
The general theme is that resistance levels are increasing over time to the three older classes of wormers.
He mentioned they showed that “quite a number of farms had drench resistance to two products and we had a number of farms where all three products were starting to fail”.
We are reminded that a low level of resistance may go unnoticed by the farmer initially; therefore, testing is important.
Take a look at the previous episode and accompanying article which talks through the simple process of testing to understand how well wormers are working.
“Once you run out of wormers, you’re pretty much out of the business,” he added.
Haemonchus contortus (the barber’s pole worm)
Haemonchus contortus, also known as the barber’s pole worm, is becoming a point of focus in the sheep farming world.
“A worm that we traditionally didn’t have in Ireland,” Gottstein added.
Gottstein described how this worm had historically been associated with warmer climates, however, more recently it has been prevalent in Ireland. There are many differences to be aware of when discussing this worm species.
Residing in the stomach and feeding on blood, this worm can drain 0.05ml/day – meaning that a sheep with 5000 barber’s pole worms could lose 250ml of blood daily.
Typically there will be no scour and often the clinical signs are comparable to what might be expected with liver fluke. He goes on to explain that this particular worm is also different in that it can cause disease in both ewes and lambs.
Treatment options for the barber’s pole worm can also include certain flukicides, therefore it is important to get your vet’s advice when managing this challenging worm species.
Class 4 orange wormer
Gottstein moves on to discuss the newer classes of wormers (4+5), which should be used as a break dose in lambs and as a quarantine dose for all incoming sheep.
The class 4 orange wormer is now available to sheep farmers in Ireland via the veterinary route. He explained that any wormer bought via a licensed merchant will be in one of the three older classes.
A break dose refers to drenching lambs with a newer class of wormer in the mid-late grazing season, to clear out resistant worms which have survived previous drenches given throughout the year.
This can help slow the development of resistance to the older classes of wormers as well as providing lambs with an effective drench.
“Going in with a break dose at some stage, then a newer product that we know is going to be highly effective and kill the vast majority of those worms, is a really good idea because it stops that factory of resistant worms inside of those lambs.”
With regards to the quarantine drench, the newer wormer classes, such as the class 4 orange wormer, should be utilised as part of the quarantine treatment – Teagasc recommend using it alongside a class 2 or 3.
Gottstein explains that the only way a worm can move from one field to another is inside a sheep, therefore having a quarantine treatment protocol is vital.
This is not only when buying in sheep, but also when sheep return from grazing away on another farm.
“As a farmer I can do everything right here, and then I can spoil it all by going and buying a bunch of hogget ewes or a couple of rams that come in and have lots of baddies inside of them, and undo all the good work.”
This episode took place at Gurteen Agricultural College where we also caught up with Ger Carey, the dry stock unit manager on the farm.
Their flock is made up of 400 ewes, split in two groups with 100 lambing in January and 300 in March. He explained they found “great benefit on the group 4”.
“We implemented the group 4 dose in the autumn time, about September when we buy in our replacement hogget ewes and our rams… The sheep are on quarantine here… Whatever remains of the lambs left on the farm will get the dose as well.”
Common worming pitfalls
Gottstein shared his experience of common mistakes being made on farm when it comes to worming sheep.
He placed an emphasis on calibrating the dosing gun to make sure the measurement is genuine.
This is easy to do, by squirting 3 or 4 doses into a calibration pot as demonstrated in the video or just use a syringe with the plunger removed – make sure this then matches with what dose you expected the gun to be giving and adjust accordingly.
On a similar note related to dose rate, Gottstein explained the importance of avoiding an underdose: “If the heaviest lamb in the group is 53kg, you need to set the dosing gun to a 55kg dose rate.”
Under dosing can promote the development of wormer resistance so it is vital that the correct dose is given.
Teagasc’s four key actions
Gottstein explained that Teagasc sat down with vets, farmers and researchers in an attempt to develop four key actions that farmers can implement to slow down the rate of wormer resistance developing on their farms.
While there are also many other ways farmers can help slow down resistance development, the following can be considered key actions which every farmer should deem achievable:
- Use only white wormers to control Nematodirus: White wormers for Nematodirus are considered “highly effective, there’s no known resistance and it’s generally not effective later on in the season”;
- Don’t treat adult ewes for stomach worms, unless there is a demonstrated need: Mature ewes are expected to have built up an immunity to stomach worms. There are some exceptions, for example thin, immunocompromised and otherwise sick ewes may benefit from a treatment, as well as those ewes affected by Haemonchus as discussed previously. Gottstein also explains “hogget ewes lambing down for the first time, they’ll need a treatment”;
- Use faecal egg counts (FECS): FECS can help determine when to treat and can also be used after treatment to check if the treatment was successful;
- Quarantine and drench bought-in sheep with a new active to prevent bringing in resistant worms: “When we’re buying in stock, we need to treat them with one of the new generation wormers and quarantine them indoors for at least 48 hours, and then turn them out onto pasture where sheep have [recently] been grazing.”
Flock forwards, not Backwards Series
This article concludes this three-part Flock Forwards, not Backwards Series.