Worming advice is really given on a farm to farm basis depending on the flock in question and the management systems on the farm.

The main issue with the existing wormers is the increasing levels of resistance to certain classes of wormers. Resistance to white drenches is common place and resistance to yellow and clear wormers is increasing. Some farms in Britain already have a triple resistance problem.

Before worming, Faecal Worm Egg Counts should be carried out to find out if the sheep are actually requiring a worm dose. Faecal Worm Egg Counts should also be carried out post worming to check the wormer has worked as well as it should have.


Bulk samples of faeces from sheep, goats and cattle can be tested for worm or fluke eggs. This gives a better estimate of the parasite burden in your flock or herd as a whole as compared to individual counts in only a few animals. Collect 10 samples into individual containers and submit them to the laboratory where the samples are individually weighed, pooled (mixed) and examined. These tests require 10 samples, otherwise the results are not valid.

Testing for lungworm larvae and coccidiosis can only be done on individual samples. Such samples should be individually identified.

Collection of Samples

  1. Gather the flock or herd into a corner of the field.
  2. Hold the animals in the corner (for at least 10 minutes) and allow them to dung.
  3. Allow the animals to move away, then select freshly voided faeces (warm and steaming).
  4. Wearing disposable gloves, completely fill a plastic pot with a fresh faecal sample.
  5. Screw on the pot lid to seal the sample and exclude air.
  6. Clean the outside of the pot as much as possible and place it in a bag.
  7. Repeat this procedure until ten samples have been collected (include a mixture of sample types i.e. pellets, firm and runny).
  8. Samples should be labelled to indicate which group has been sampled and to allow individual testing if this is considered necessary.
  9. Remove and dispose of the gloves hygienically.
  10. If possible samples should be delivered on the same day as collection. If this is not possible, samples must be kept cool (NOT FROZEN) until delivered.


  1. Worm eggs can hatch in faecal pellets or dung pats that have been on the ground a period of time. This reduces the worm egg count. Select only fresh samples.
  2. Faeces from farm animals can carry disease organisms dangerous to human health. Always wash your hands after collecting faecal samples and before eating, drinking or smoking.