The heavy use of dewormers (anthelmintics) over the past 20 years has unfortunately led to a significant amount of worm resistance in horses and donkeys. This means that some dewormers are no longer effective at eliminating worm burdens in some horses / donkeys. These problems can be overcome relatively easily by monitoring the faecal worm egg count (FWEC) of all horses on a yard at regular intervals. This ensures that only those individuals with a significant worm burden are treated using appropriate wormers at appropriate times, thereby reducing the problem of resistance. 

The FWEC is a relatively simple procedure that only requires a small amount of input from the horse owner. To do this we need you to provide a small amount of your horse’s droppings, approximately 10g or a heaped teaspoon size (selected from more than one nugget - ideally at least three). The sample must be fresh as possible, ideally being delivered to the clinic on the day of collection. Alternatively, samples can be sent by first-class post using one of our free-post sample kits.

Samples can also be collected into a clearly labelled sealable container, such as a plastic sandwich bag and brought in within 24 hours along with a completed request form. Air should be excluded from the bag / container.

Click HERE for a simple guide to collecting a faecal worm egg count sample. 

To download a FWEC request form (if you are not using one of our free kits) which is required for sample submission: click HERE for the submission form for 4 samples or less and click HERE for the submmission form for 5 samples or more.

For those samples coming from a larger yards, it helps to call our team in advance on 01622 813 700. 

Following microscopic analysis of each sample individually, we aim to contact you with your results within 48 hours. This gives your vet / SQP the opportunity to advise you on any further treatment, considering our knowledge of your horse. This also gives you the opportunity to ask any questions, a service of which is all included in the lab fee. By running worm egg count tests 14 days after worming, we can see how effective the wormer has been at eradicating the worms. This is know as the ‘faecal worm egg count reduction test’ - FWERT. Please call us to discuss the details of how to run this test.

Unfortunately tapeworms are not reliably detected by routine worm egg counts, so a tapeworm or saliva (or blood) test should be performed at least once a year (usually autumn). Often with the results showing no treatment is required.

Young horse's (upto 5 years of age) are most susceptible to picking up large numbers of small redworm larvae, many thousands of which can accumulate as encysted larvae in the walls of the large intestine. These larvae can then cause a serious disease called larvae cyathostominosis. Unfortunately there is no available diagnostic test to determine if horses are carrying large burdens of ‘encysted’ (immature) small strongyles. Therefore, it is advisable that all young horses less than 5 years old or others at particular risk are treated for these larval worms in the autumn / early winter (usually with Moxidectin which is believed to be effective against the larval stages of the parasite).

Older horses that are considered to be at low risk of accumulating large numbers of larvae do not necessarily need treating; the small redworm blood test may be useful in these cases to confirm that no treatment is required. The test estimates the total burden of small redworm in the horse's body (adults and larvae) and therefore is of little value in horses that have repeatedly high FEC results or at high risk for other reasons since the result of the blood test will also be high.  Our vets and SQPs can advise you further if you have any questions.