What to do when
A healthy adult horse can follow a very simple pattern of testing, which we call a targeted worm control programme.
Worm egg count every three months through Spring, Summer and Autumn. Test for tapeworm every six months in either Spring and Autumn or Summer and Winter. Worm only the horses that need it based on the test results.
In the winter, we also need to be aware of a specific stage of the redworm lifecycle that can be very dangerous to horse health.
When the weather turns cold the larvae of this parasite burrow into the gut wall and hibernate in the horse’s belly. Many thousands can hang out here and then emerge all-together in Spring when the weather warms up. When this happens it can be such a shock to the horse’s intestines that it can bring on a very severe type of colic that is hard to treat.
Horses can be protected from this either by doing a blood test through your vet to make sure they’re clear or by giving a specific wormer that can target larval as well as adult stages of the worms.
Other parasites that can affect horses include pinworm, lungworm, liver fluke and bots but tests and treatments don’t need to be done regularly, only if we spot certain symptoms.
Worming ONLY when we need to treat
Even though there are many brand names of wormers available, there are just five different worming chemicals available in the UK. The more often we use these the chemicals the more opportunity we give the worms to evolve ways that stop the worming treatment from working. We call this wormer resistance.
All of the wormers now have some documented resistance problems. It means we can no longer give a wormer and just expect it will work. With no new wormers being developed, we need to carefully protect the ones we have. This means testing first and using them only when we know we need to rather than ‘just incase’, and selecting the right chemical. Ask your vet or a qualified person at your testing lab, saddlers or feed store where you buy your wormers who can help with this.
Testing for Resistance
When worming treatment is needed, we can test again to make sure treatment has worked. This is called a reduction test. Repeat worm egg counts 10-14 days after worming and EquiSal saliva tests two months after worming. If there is no resistance the reduction test results should come back low.