Small Strongyle Worm Management – Seasonal Guide

Use this year-round guide for managing worms, particularly small strongyles, in healthy, adult horses from the age of 3 years.

Young horses, broodmares, seniors and horses with health conditions (e.g. Cushings) require a tailored worm control program.

MOST IMPORTANTLY always integrate FECs with good pasture hygiene and horse husbandry strategies.

Gear up in SPRING!

Spring is Faecal Egg Count (FEC) Time!

Warmer temperatures and good moisture means pasture grass will grow quickly. These are the best conditions for small Strongyles to begin laying eggs.

So, about a month into Spring… undertake a faecal egg count (FEC) for each horse and record the measurements (eggs per gram or EPG), for your future reference.

  • LOW (0 – 100 EPG) – No treatment necessary.
  • MODERATE (between 100 and 200 EPG) – No treatment, FEC monitor in 4-6 weeks or after warm, moist weather.
  • MODERATE-HIGH (between 200 and 500 EPG) – Treatment advisable, monitor with additional FEC at the end of the efficacy period (you will find this information in the product manufacturer’s statement).
  • HIGH (more than 500 EPG) – High-egg shedder. Treatment is necessary. Continue to monitor these horses.

Always treat HIGH egg-shedding horses with a targeted treatment (read the product label) and continue to monitor with FECs.

Exercise restraint in SUMMER (and during extended dry conditions)

In summer, non-resistant worms will be trying to survive hot, dry pasture conditions so, only use worming chemicals at this time if it’s absolutely necessary. We need these worms to help keep the population of resistant worms at low levels.

  • Continue to monitor high egg-shedding horses with FECs every 8 weeks or so, but BEFORE any treatment (otherwise the result might be false).
  • About 4-6 weeks after significant summer rain, it is useful to undertake FECs for all horses (keep an eye on the grass – is it growing? If the grass is growing, worms will be active).

Treat for all parasites in (late) AUTUMN

In late autumn, the weather is cooling off and is less attractive for Strongyles to be laying eggs. This is the best time to treat all horses (including low-egg shedders) for all parasites including bot fly larvae and tapeworm.

Treatment at this time is also the time where the treatment is likely to have minimal impact on our precious dung beetles!

  • Use a product with Praziquantel for treatment of tapeworm. Wormers often identify this ingredient by using ‘Plus’ in the label. Ivermectin/abamectin will target bots.
  • Continue to monitor and treat high egg-shedding horses.

Important! Horses that have a track record of no, or low egg test results, generally only need worming once a year – LATE AUTUMN IS THE TIME TO DO IT!

Scroll down to download this guide as a poster!

Have a break in WINTER

In most parts of Australia, the weather cools sufficiently for this to be a time of low Strongyle egg production, but our winters are seldom cold enough or long enough to seriously deplete eggs that winter-over in the pasture.

The main job at this time of the year is to:

  • Treat your horse for bots and tapeworm if you didn’t get around to doing this in late autumn.

Become Worm Wise

  • When the grass is growing, the worms will be laying eggs so, after warm, moist conditions (yes, these can even occur in winter) be FEC-vigilant!
  • This means that in the tropics your FEC-ing regime will be governed by the wet and dry seasons and on irrigated pastures it will be year-round.
  • Veterinary advice always takes precedence over FECs, especially where there is doubt about a horse’s wellbeing.
  • Learn to do FEC-testing yourself (it really is not that hard!) and test your horses at your own convenience. It is easy with the right support, equipment and a manual.
  • For more about worm management, read The Ultimate Guide to Worming Your Horse.

Why not do it yourself? Count Your Eggs Before They Hatch!

You can learn more about managing worms in horses and do FEC testing with the help of Evidence Based Worming’s stress-free, do-it-yourself manual!

Get your copy and get in control of your horse’s worming program! Click here to learn more about managing worms in horses…

Jude Matusiewicz, Post Grad. Certificate Animal Science (Parasitology)

Jude has combined her professional expertise in equine gastro-intestinal parasitology with her passion for working with people to enable change. Jude’s goal is to provide all horse owners with the tools to manage environmental populations of Strongyle worms as a hedge against increasing resistance to anthelmintics.


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