08/04/2025
📣Let's talk about worms - we need your help 🪱
Small redworms (cyathostomes) have once again caused serious disease and fatalities this winter, especially in youngstock.This dangerous disease is seen mainly in horses upto 6-7 years old and occurs from October through to March.
The immature worms (the larvae) which cause this winter disease do not lay eggs and worm egg counts in the autumn/winter months can be misleading.
April and August are the peak months for egg laying by the adult worms with the eggs being passed out in the droppings.
In general, horses don’t show clinical signs during this time of year but store up this trouble for the youngsters in winter by shedding eggs in their poo.
By doing worm egg counts in April, June and August, you can identify the big shedders and target your worming. Worm egg counts done monthly is ideal but the April, June, and August counts are a good strategy too.
Resistance to wormers is undoubtedly increasing and there is no sign that new worming drugs will be produced in the immediate future.
In many situations we can kill these spring/summer adult worms from the big shedders without using the wormer moxidectin (Equest), which is our lifeblood when it comes to treating the sick youngsters in the winter. This tactic also reduces worm resistance to moxidectin.
So worming the big shedders is the way forward. The high shedders may need a dropping check after worming to ensure they were not resistant to the wormer used, we cant tell this, until after worming and looking at the droppings.
We believe this to be a good strategy for horse and pony owners to consider egg counts from your horse’s droppings during this spring/summer season to help fight back against this disease and drug resistance.
So go and get your worm egg counts done and help us beat this horrid disease.
Correct way to collect a dropping sample
Try to avoid sampling within ten weeks of the previous wormer, as this effects results. Take a small amount of manure from 3 dung balls, taken from across the pile of droppings, sample less than 12 hours old and place in zipper bag and remove air. Don’t use frozen samples or diarrhoea samples. 99% of eggs in a dropping egg count will be small redworms.
