As the clocks change, the nights draw in and the weather begins to feel colder, we start getting lots of questions about winter worming, what wormers people should be giving, what tests to do and most commonly when is it cold enough to worm for the encysted redworm.
We are going to try to answer some of the most common questions we get asked. However before we do we need to discuss the single most important thing we should be thinking about when we plan our worming programme, and that is resistance.
Resistance to wormers
There are currently no new wormers being brought to market by the drug companies. Without new drugs to kill the worms we must rely on the ones we have been using for years. Except the problem is we’ve spent years worming every horse, every 6-8 weeks even if they didn’t need to be wormed, and we now have a population of worms that have evolved and become resistant to the drugs. Some horses are being given wormers that simply aren’t going to kill the worms.
So with that in mind we should only ever be worming if absolutely necessary and the way we do this is with a planned programme and regular testing.
What tests should you do?
We would recommend three faecal worm egg counts throughout the year in March, June and September and one saliva test which tests for tapeworm in November/December. With high risk horses we would recommend doing two saliva tests, one in June and one in December. High risk horses would be those on large yards with lots of different horses coming and going and/or no communal worming programme. If your horse has had a previous high result for tapeworm then we would also recommend testing twice a year.
There is also a blood test available to test for encysted redworm but these can be quite expensive as they need to be done by your vet, whereas you can do the saliva tests and collect the poo samples yourself.
What wormer should I be giving in the winter?
At this time of year the we are mainly looking to target the encysted redworm and tapeworm. The only wormer we have to treat encysted redworm is Equest (Moxidectin). If you need to worm for tapeworm, because your horse’s saliva test has come back high, then you will need to get an Equest Pramox, which treats both the encysted redworm and tapeworm. There are other wormers that treat tapeworm so you could use a different wormer for the tapeworm but you will still need to treat with an Equest.
What are encysted redworms?
At this time of year the encysted redworm burrow into the gut lining and will sit there quite happily until the spring. As the weather get warmer they can emerge in large numbers and cause colic. They can also migrate around the body via the blood vessels and can cause nasty complications for our horses. They cannot be treated with anything other than Equest.
When should we be giving the winter wormer?
It is important to wait until after the first proper, hard frost and by this we mean weather where we have 10 consecutive days at below 10 degrees. If we worm too early we risk having to worm again at the end of the winter which just contributes further to the problem with resistance. The ideal time is between December and February.
There are of course always exceptions to the general rules and we would recommend contacting your vet to get specific advice particularly if you have young stock or pregnant mares.
If you are on a livery yard ask your yard owner to put together a yard plan so that everyone is following the same plan, sampling at the same time and worming at the same time.
