With autumn now upon us, it’s important to know the most effective practices when it comes to autumn worming for horses. The consequences of ineffective worming can be huge, and with wormer (anthelmintic) resistance already a widespread problem, a targeted horse worming programme is essential. This blog article discusses the importance of targeted, responsible worming and how to manage your horse’s worming programme this autumn.
In the past, horse owners would apply a ‘blanket’ approach to worming, and this is still something often seen on large yards. All horses on the premises receive a deworming treatment at the same time.
However, it is estimated that only a small proportion of treated horses will actually require worming, meaning many wormers are given unnecessarily. Worming unnecessarily can lead to an increase in anthelmintic resistance, a problem which is already widespread. The blanket approach also means some owners will be using the wrong wormer or using an incorrect dosage, which will also contribute to wormer resistance.
Instead, carrying out worm counts for horses and treating as necessary is recommended. This targeted approach has several benefits over traditional methods.
Targeted worming:
Wormer resistance - or anthelmintic resistance - means that a high proportion of parasites are no longer killed by the wormer administered.
This has a few causes, but the most common is using wormers too frequently. The wormer kills susceptible worms before they reach maturity, meaning only those that are genetically resistant survive. They go on to breed with another partially resistant worm to produce resistant offspring.
Under-dosing can also lead to wormer resistance. This helps worms that are already partially resistant to survive and breed.
If left unchecked, wormer resistance can render even the most potent deworming treatments ineffective, leaving horses vulnerable to the harmful effect of worms.
Carrying out regular worm counts for horses is best practice as it allows owners to assess whether their horse needs worming, and treat accordingly. This will slow the development of resistance, white rotating between different treatments can help prevent resistance from emerging in the first place.
The CANTER Initiative (Controlling ANTiparasitic Resistance in Equines Responsibly) has a website with some useful information for horse owners, including advice on controlling parasites and assessing your horse’s risk profile.
A strategic approach throughout the year is vital when it comes to effectively worming your horse, while also reducing wormer resistance. Autumn is a critical period for target worming, as horses are more susceptible to certain types of worm during this season.
In autumn, we should be targeting tapeworm, encysted small redworm and large redworm.
Tapeworms don’t reliably show up in a standard faecal worm egg count. Instead, owners must test using either a saliva test or a blood test. Saliva tests measure the antibodies to the tapeworm parasites present in a horse’s saliva, and owners can do the test themselves using a swab collection kit. This is then tested and scored to determine whether the horse needs worming for tapeworm.
Encysted small redworms are another risk in autumn, although these can be a problem throughout the year. They can cause diarrhoea and colic, and cannot be detected by a faecal worm egg count. We recommend treating your horse for this type of worm in autumn or winter, after the first frost.
Check out our other blog article on How Often Should I Worm My Horse? for more information on worming.
It is best to follow a set horse worming programme throughout the year, which uses regular faecal worm egg counts to inform the frequency and type of worming. At Avonvale Equine Vet Practice, we offer a worm control package to our clients. This annual package includes three worm egg counts, a weigh tape, an Equest Pramox wormer (usually administered in the winter) and unlimited, up-to-date advice from our vets.
If you require any advice on autumn worming for your horse, or you would like to take advantage of our annual worm control package, please contact us on 01295 670 501.
