How to plan a Strategic Worm Control Programme

Good worm control starts with knowing which parasites could be a threat to horse health at which times of year and using worm counts and tests to monitor infection levels in the horse, only adding wormer doses as they are needed. Combine this with pasture management and animal husbandry techniques to reduce the parasite challenge to your horse. Westgate Labs advises...

There are two tests that should form the basis of an effective targeted worm control programme – worm egg counts for redworm and roundworm and the EquiSal saliva test for tapeworm. Both tests give statistical results for the levels of parasites present that can be used to determine whether the horse needs treatment or not. You may also need to consider bots, pinworm, lungworm and liver fluke in your programme if you suspect a problem

When should you test?
A mature, healthy horse can follow a very simple pattern of testing and dosing. The basic idea is to test a small dung sample about three times a year to check for the presence of redworm and roundworm (ascarids) and a saliva sample twice a year to test for a tapeworm infection.

A suggested programme
Worming is only required if the tests indicate infection above a certain level. Complete the year by treating for possible encysted redworm in winter. Foals, youngsters, neglected or older horses will require more attention.

The following programme is a good basis for a healthy adult horse:
    SPRING    Worm egg count for redworm and ascarids.
                    Saliva test for tapeworm
    SUMMER  Worm egg count for redworm and ascarids    
    AUTUMN   Worm egg count for redworm and ascarids   
                    Saliva test for tapeworm
    WINTER    Worm for possible encysted redworm, resistance test to check drug efficacy. 

Encysted stages of redworm are not mature so don’t lay the eggs which are counted in the dung sample. It is important to treat with an effective product in the winter months (December to February) then you can rely on your worm count results over the next season.

Once you’ve got the result, what next?
An explanation will be given by the laboratory to help you decide whether to worm or not. Alternatively  you can ask an SQP, vet or pharmacist for advice, who will want to discuss your horse’s test results in the context of worming history and general health, and can then advise on an appropriate wormer to use if this is required.
Westgate Laboratories has a friendly, knowledgeable team of SQP’s and the follow-up advice is included free of charge in the worm counts and testing service.

Good pasture management and animal husbandry techniques will also help to reduce your horse’s worm burden:•    If possible keep horses with the same grazing companions, not constantly changing groups.
    •    Poo-pick as much as you can, at least twice a week to keep parasite levels down.
    •    Keep stables, buckets and communal areas clean. Disinfect from time to time.
    •    Rest and rotate grazing and don’t overcrowd fields.
    •    Cross graze pasture with other species, for example sheep.
    •    Keep new horses separate until tested and treated accordingly.
    •    Don’t worm and move; after worming ensure horses stay on the same pasture for a few days to help slow down resistance.
    •    When first starting to use a targeted worming programme all horses should be tested, at a point when worming is due or slightly overdue, so as to get a true result.

A Veterinary View

Carolyn Cummins MVB Phd MRCVS, consultant vet to Westgate Laboratories, gives her view on the importance of good parasite control:

Why do you think good worm control is important?
Working as a first opinion equine vet I see a wide and varied caseload. Every year this includes horses that are suffering from a severe worm burden. In some circumstances this is due to neglect or other underlying illnesses. More worryingly, in others, these are horses with owners who believe that they are worming their horses appropriately.
In these horses problems can arise from worming at the wrong times of year, not using the appropriate wormer, under-dosing, or overuse of a particular wormer leading to resistance so that the drugs we have are no longer effective against the parasites that are a threat to horse health.
A horse suffering with a severe worm burden can go from an apparently healthy horse to a severely ill one in a very short space of time, hence the importance of a regular testing regime.

This article first appeared in the July issue of Equine magazine. Back issues and annual subscriptions can be purchased securely online from www.theequinestore.co.uk