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What are fecal worm egg counts?

Fecal Worm Egg Counts (FWEC) also known as Fecal Egg Counts (FECs) involve scientifically counting the presence of parasitic worm eggs in the manure (feces). The egg counts provide an indication of the level of parasitic worm burden in that particular individual animal (If collected from an individual), or herd (if multiple samples are collected from a herd).

 What worm species are included in FEC?

Nematode worms are included in FEC tests, predominantly

• Strongyles (small and large), and
• Ascarid (Parascaris equorum)

Species NOT included in FEC are (but not limited to) tapeworm, botfly, and pin worm.

 Why bother when there are species that are not included?

• FEC will help to you avoid unnecessary drenching/worming. Which can result in
  • saving money,
  • sustaining efficacy of drenching products longer term (reducing speed of resistance issues)
  • supporting beneficial bugs such as dung beetles
• FECs can assist you to
  • implement parasite control programs that are specific to other species (such as botfly) that will increase success rate of control long term, and
  • discover any existing resistance issues so that appropriate measures can be put in place to establish a more successful worm management program.

 Are there drench/wormer resistance issues in Australia?

Yes, the main problem is resistance of small strongyles to a chemical class known as benzimidazoles (e.g. fenbendazole, oxfendazole, oxibendazole). There is also early indications of small strongyles resistance to the chemical class known as macrocyclic lactones (e.g. abamectin, ivermectin, and moxidectin).

What causes resistance issues?

• Overuse of drenches (frequent, continuous, unnecessary treatment regimes year upon year)
• Using the same chemical year upon year without rotation to a different mode of action (a different chemical that acts differently in the way it works).
• Under-dosing
• Drenching/de-worming at the wrong time of year/season

When and how often should I get FECs?

FECs should be conducted prior to drenching to provide an indication of the worm burden.

If the count is low, and it is ‘off season’ for botfly, then drenching is likely unnecessary[1].

FECs can also be conducted 14 days after drenching to discover any chemical resistance issues.

[1] Dependent upon historical parasitic worm control program.