Test don’t guess to curb wormer resistance
Conducting regular Faecal Egg Count (FEC) tests throughout the grazing season helps to maintain growth rates and avoid unnecessary and expensive treatments.
Traditionally, many farmers have dosed stock at set points in the year to manage worm burdens but with resistance to many anthelmintics growing, an informed treatment plan can help.
Elizabeth Barrett, Fauld Store Manager
Elizabeth Barrett, our award-winning Store Manager at Mole Country Stores in Fauld in Staffordshire, said regular testing can help safeguard the effectiveness of anthelmintics, as well as saving farmers money.
She said: “Using wormers unnecessarily is a costly exercise and adds to the anthelmintic resistance pressure on farm.
“Many factors affect when worm counts are high such as the weather, previous grazing history, animal condition and stress. All of these factors should be considered when planning which animals need treatment and when.
“The time when the worm counts peak varies each year. Just because a farmer may have wormed one year at a set time, it doesn’t mean that’s the best time to worm again or the treatment is even necessary.”
Testing worm burdens using FECs also means you can identify the types of worms present and use the most suitable wormer for that species.
How to take FEC samples Regular FECs are essential to understand when lambs need treatment and we suggest taking samples every three to four weeks from at least 10 random animals in a group.
Miss Barrett said: “It takes approximately 21 days for larvae from the pasture to develop into egg-laying adults following ingestion, so egg counts should be carried out every three to four weeks throughout the grazing season.”
Dung samples should be less than four hours old, stored in an airtight container or plastic bag and kept cool until ready for testing.
The sample, which should be the size of a golf ball, can then be analysed at home, if the farmer has the equipment and the training, or by an animal health professional.
Miss Barrett said: “You can purchase a FEC kit from any of our stores or at moleonline.com and have your flock’s sample analysed by our Molecare Farm Vet team. The results are usually back in a couple of days and one of our Registered Animal Medicine Advisors will contact you to discuss the course of action. Ideally, we would like all farmers to bring in dung samples before buying any treatment to see whether dosing is necessary.
“Where the eggs per gram (EPG) falls under 250, no treatment is recommended. However, above this threshold, it is. A high worm burden would be classed as 750 EPG or above, with a medium risk from 250 to 749.”
Drug resistance is a costly business, with a study in 2020 estimating it costs the sheep sector £3.15m alone.*
Testing for resistance Miss Barratt added: “It’s critical farmers test rather than guess there’s a problem to help curb wormer resistance on farms.
“They must also understand if they have wormer resistance and to which groups by taking further FEC samples post-drenching.
The time between drenching and taking a sample depends on the active ingredient.
“If you haven’t already done so, I’d highly recommend you speak to your animal health advisor about conducting post-drenching tests to see if you have any resistance on your farm.
“The last thing you want to be doing is using a product that isn’t working, which has cost you money and is impacting your stock’s daily liveweight gain, which is also a significant cost to your business.”