Sheep Faecal Egg Counting

Click here for printable version PDF

Faecal egg counting is usually performed on a group of sheep:

  • The same age
  • The same reproductive status
  • Grazing together in the same field
  • Having had the same worm treatments. 

Individual testing can be done if required please telephone the Office to discuss.

Collection of faeces

  • Simply walking around a field and picking up “fresh” faeces samples is not considered to be reliable
  • Easiest way to collect faeces is to loosely gather sheep in the corner of a field for 5 to 10 minutes, then let them walk away.  Fresh samples can then be collected from the pasture
  • At least 10 sheep should be sampled (this is generally accepted as an acceptable compromise between cost and repeatability).  Each sample should be at least a heaped teaspoon full. 
  • Sheep should be healthy and have access to pasture and/or feed before sampling.
  • Samples must be fresh when collected (less than 1 hour old) and then kept cool (not frozen) in an air tight container or plastic bag
  • The individual faeces samples should be collected separately and will be mixed in our laboratory to ensure a more accurate average result is given
  • Samples should be delivered to the Practice on the same day as collection, during Office hours
  • If samples are delivered to us before 10am we will try and get a result to you before the end of the day
  • If faeces is too old some eggs will have hatched and the FEC will be an underestimate
  • We recommend that separate groups of lambs and/or ewes are tested separately; this allows treatment decisions on a group by group basis.  They will not all be the same. 

Please bring with you the following information to enable us to give you the best advice:

Number of animals in the sampled group

The length of time on the current pasture

The age of the animals

The date they were last dosed on and the dose that was used

The condition of the animals

The length of time they are expected to remain on the pasture

Resistance Testing - Faecal Egg Count Reduction Test (FECRT)

A FEC is taken prior to dosing and should be at least 300epg.  A second FEC is then done following the treatment to measure it’s effectiveness.  The timing varies depending on the treatment given.

  • White drench, BZ, e.g. Rycoben SC – sample 10 to 14 days after treatment
  • Yellow drench, LM, e.g. Levacide 3% – sample 7 days after treatment
  • Clear drench, ML, e.g. Noromectin Drench – sample 14 to 16 days after treatment
  • Orange drench, AD, Zolvix – no resistance yet

If you would like to discuss faecal egg counting or anything else with regard to worming sheep please telephone the Office. 

Click here to print a form to accompany faeces to the Practice PDF

Click here for printable version PDF


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