Faecal Egg Count Testing

We encourage horse owners to incorporate Faecal Egg Count Testing - FEC - into their worming programme.

FEC tests will enable the identification of horses and ponies that have a worm burden - only these horses will then be treated.  

Click here to download a copy of the FEC info sheet


FEC tests are available through your vet and are provided in the form of a convenient courier-pack system from Horse Wormers Direct in association with Gribbles Laboratories. 

 What is a FEC Test useful for? 

FEC tests can detect the presence of egg-laying adult stages of Small and Large Redworm as well as Large Roundworm. 
FEC’s are normally reported as eggs per gram (epg).  FEC results will help you to target your worming treatments by only dosing horses with a significant worm burden (e.g. >200 epg).

Some horses and foals may require worming at much lower egg counts. Consult your vet for advice.

To check your worming programme is working, you can take a test before and after treatment. A failure to completely reduce the worm burden in your horse may indicate resistance to the type of wormer you used. 

FEC's don't detect Encysted Redworm, which is the most potentially harmful stage of the redworm parasite. Horses can have burdens in order of several million encysted larvae and yet show a negative orlow reading - <100epg. (3) Therefore, you need to strategically drench for the encysted and larval states of redworm at least once a year in late autumn / early winter. I Dowdall et al. (2002) Veterinary Parasitology 106, 225-242

What parasites can a Faecal Egg Count Test Identify?

Small Adult Redworm 
Large Adult Redworm 
Large Roundworm



Encysted Small Redworm




How does it work?
Very simply, dung samples are collected, collated and are sent to Gribbles Veterinary Laboratories.  The tests are interpreted by Gribbles parasitologists and the results are shown as the number of eggs per gram (EPG). 

The EPG reading indicates how many eggs active adult worms have laid in a small sample of dung and it will provide an indication as to the level of  the worm burden the horse is carrying. 

A PDF copy of your FEC test result will be emailed to you. If there is cause for concern, we recommend consulting your vet.  As a general guide a count of 100—200 is considered low, 200—500 is considered moderate and anything above 500 is considered high. 

To view a copy of an EPG test result from Gribbles:  

This FEC test was commissioned by a pony club.  The first test showed a high reading for Strongyles
Click here to view the FEC test result:  

The horses were drenched with Morabec and a FECRT was completed fourteen days after drenching 
Click here to view the FECRT result:

How Can I Order a worm egg count:
In the interests of equine health, we are offering FEC’s at a reasonable price to all our clients.  Janine Wallace manages the FEC service.  You can contact her by email or phone:

Email Janine at:  wallace@wormersdirect.co.nz
Phone or text: Janine on 021 488 093 to order your pre-paid FEC Kit. 
Text 'FEC Kit' to Janine and she will call you back

 A complete collection kit will be posted to you and will contain:
· Surgical gloves - for picking up the dung  
· Bags for each sample required (only 50 grams of fresh dung per horse is all that is required - a tablespoon amount)  
· Labels - to identify which horse the sample is for  
· Form for Gribbles with instructions  
· Courier Envelope for the samples to be despatched to Gribbles laboratory  

For your information the dung needs to be as fresh as possible and firm:  
Please select a fresh dung, preferably as it leaves your horse. Once in the bag the eggs are sealed and will not deteriorate.  If an old dung pile is used, then the eggs may have fallen out and a false low reading is given, which could be dangerous if you were planning not to worm your horse based on this false low reading from that dung sample.  If there is a delay in getting the sample to the laboratory, store it in a fridge. The lab report is normally available within 24—48 hours after the sample arrives at the lab. This report will be emailed to you.  

What is the cost of a complete Faecal Egg Count Collection kit in New Zealand? 
Individual FEC's cost $35 each. Included in this cost are sample bags, labels, gloves and a courier pack to get your sample to Gribbles and your laboratory fee. 

The most economical efficient way to do egg counts is to purchase our pre-pay FEC Ten Pack, which will cost you $15 per horse plus GST.  You must test ten horses at the same time.  If you don't have ten horses, then 'dial up a friend' and combine resources - it's cheaper that way.  

You will be invoiced upon your order and your pack must be paid for prior to dispatch to your address. 
We accept a cheque or electronic payments.  (electronic is the most efficient method)
The cost of your FEC kit includes the cost of the kit, courier fee and laboratory fee.  
Email wallace@wormersdirect.co.nz  to order your FEC pre-paid kit, or phone Janine on 021 488 093 
or 0800 292 766

For New Zealand clients - if you are ordering a Faecal Egg Count kit and you are on rural delivery, we recommend you allow 2-3 days for reception of the kit. Your laboratory results are generally available within 24 - 48 hours from the time the samples have been received at the laboratory.  Gribbles are excellent and generally the results are returned the next day, but it is best to plan it into your farming schedule so that all goes smoothly in case of unforeseen delays.  We also recommend that you do not send your samples on a Friday as the couriers do not normally operate over the weekend.

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