Agriland Media is delighted to collaborate with Elanco Animal Health to bring you part two of the Flock Forwards, not Backwards Series.
Practising in Co. Kilkenny, vet, Kieran Devaney shared his thoughts on managing sheep worms and getting results, while also trying to limit the contribution to wormer (anthelmintic) resistance.
Resistance is described as the ability of a worm to survive a drench and pass this ability onto its offspring.
He urged farmers to talk to their vet and remember that flock health plans are dynamic, therefore regular contact between both parties throughout the year is important.
Both anthelmintic and antibiotic resistance are terms we hear frequently in the farming industry. It is vital that we recognise their differences when it comes to managing them.
Devaney explained that critically important antibiotics should be kept on ‘the top shelf’ and used as little as possible.
Contrastingly, when it comes to anthelmintic resistance, he explained the importance of incorporating the newer classes of wormer now, in order to help preserve the older classes.
Deciding when to worm
Building on the learnings from Co. Derry farmer, Clement Lynch, in episode one, Devaney echoes the same message emphasising the importance of monitoring lambs in order to decide when a wormer dose is necessary.
He said: “Farmers should be taking faecal egg counts (FEC) every three weeks throughout the grazing season.”
This will give an indication of the number of adult egg-laying worms inside the animal. The results can then be interpreted by your vet, alongside the wider clinical picture, to aid in decision making on whether or not a dose is warranted.
While considered a simple task, dung sampling must be given some thought to obtain a reliable result.
Devaney described a good sample as “warm when collected” indicating freshness. Secondly, it should be delivered to a local practice as soon as possible for analysis.
A collection of 10-15 samples (or 10% for larger groups) is recommended in order to ensure the group is represented.
Devaney also discusses the benefits of weighing lambs regularly to track growth rates, as worm burdens can be responsible for a drop in daily live weight gain.
How to work out wormer resistance levels on-farm
Described as ‘insidious’, wormer resistance creeps up on farmers, and low levels may initially go unnoticed; testing is therefore vital. Resistance levels will differ from farm to farm, and even from one worm species to another.
Devaney added: “The best way to identify resistance is to do a faecal egg count reduction test (FECRT).”
The test involves:
- Collecting dung samples from 10-15 lambs in a group and marking them;
- Administer chosen worm drench, if deemed necessary;
- Collect another dung sample from the same 10-15 marked lambs either seven days later (if treated with class 2 wormer) or 14 days later (if treated with a wormer from class 1, 3, 4 or 5). Your vet will be on hand to help decide how many days post-treatment the second sample should be collected;
- The test calculates the difference in worm egg count before and after treatment and therefore figure out by what percentage the egg count was reduced. From this we can tell how effective that particular wormer is on the individual farm against the worm species present, which can dictate how this class should be used in the future.
Taking a holistic approach to worm management
Looking at the bigger picture is vital when it comes to managing worms effectively. Attempts should be made to reduce reliance on wormers.
Devaney described the benefits brought by mixed species grazing of cattle and sheep, as well as rating the risk of pasture. For example, ground carrying ewes and lambs in the early season will make it more contaminated as the year progresses.
He also touched on the topic of breeding and selecting for sheep better able to deal with worms.
Role of the class 4 orange wormer
All too aware that wormer resistance poses a huge threat to the sheep industry, Devaney described the class 4 orange wormer as having “a really important role to play” in Ireland.
As a prescription only medicine, he explained he prescribes the product as a break dose for lambs in the mid-late grazing season and as a quarantine dose for all incoming sheep.
A break dose can be described as a treatment to clear out worms that have survived previous treatments of one or more of the older wormer classes.
This will help slow the development of resistance to the older wormer classes, as well as give the benefit of an effective drench that will remove worms that could be holding lambs back.
Devaney explained the importance of having a quarantine protocol in place to help reduce the risk of bringing in infectious diseases as well as endoparasites (such as worms) and ectoparasites (such as scab).
“You don’t want to bring in resistant worms onto your farm,” he said.
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 a class 3.
The aim is to protect your farm by removing resistant worms from incoming sheep – followed by housing.
Flock Forwards, not Backwards Series
Stay tuned to Agriland for episode three next week, when Elanco Animal Health technical consultant, Brian McConnell, speaks with head of sheep knowledge transfer at Teagasc, Michael Gottstein.