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worm egg counts

Equestrian Faecal Worm Egg Counts and Tape Worm Testing Kits experienced suppliers of wormers, testing kits, health supplies, supplements and equine herbs.

Faecal Worm Egg Counts for Horses

What does a worm egg count actually count?

The results are measured in EPG or eggs per gram which indicates the actual level of worm eggs found. When we use the symbol < followed by a number such as <200 EPG this means that the level of worm eggs found is less than 200 per gram. A count of less than 200 EPG 

would be considered a low count and would indicate to us that your worming measures are working which would in turn suggest delaying the next routine treatment. A count between 200 EPG and 1200 EPG would be considered as a medium count indicating that the particular horse in question needs treatment and perhaps the overall treatment strategy needs some attention. If the count is more than 1200 EPG it is a high count that horse should be treated without haste and the management and worming strategy and planning will need considerable attention. 

The dangers of encysted smallredworm

Results cannot show encysted stages of redworm potentially the most harmful stage of the redworm parasite. Horses can have burdens in the order of several million encysted larvae yet show a negative or low count (<100 EPG) FWEC  (Dowdall et al. 2002, Veterinary Parasitology, 106, 225-42). 


Pinworms are not reliably detected in standard egg counts because they don't consistently lay eggs as part of their life-cycle and bots are not identified in FWECs either. Bots will rarely appear in a dung sample. FWEC's are not a definitive test for tapeworm. A separate testing method is used for tapeworm. Eggs are not shed at a constant rate and immature parasites don't lay eggs so a FWEC will only ever provide a snapshot of a horse's adult worm burden at that particular time. FWECs are useful to identify which horses are shedding high numbers of worms but are not the whole answer.

Consult your SQP for advice on how and when to treat for parasites that are not detected.

Factors effecting the results


Results usually refer to Strongyle eggs which is redworm the most common parasite that affects horses. When you interpret your results a full risk assessment needs to be undertaken and we could never specifically say that NO treatment is necessary as there are many factors to be considered. There are occasions when the results are less than accurate due to variations with regard to sample taking, seasonal timing and the actual larvicidal cycle. The age of the animals can also affect the result. Older animals tend to have greater resistance to internal parasites, so the correlation between number of parasites and worm egg count is not always as clear as with younger animals 

Free advice on all worming and testings issues from an E-SQP provide independent advice and horse worming and testing programmes that are impartial. Alongside our range of horse wormers we have an extensive range of equine herbs for the equestrian.