Print this page



Worms in excessive numbers cause many gastrointestinal problems in horses, ponies and donkeys. A combination of pasture management, worm egg counts (WECs) and targeted worming will ensure that these worm burdens are kept to a healthy level and minimise the risk of disease. 
XLEquine worm managemen in horses2
XLEquine worm managemen in horses1.5
It is important that you discuss each premises and horse needs with your veterinary surgeon, so advice can be tailored to individual circumstances.

On premises where there is little movement of animals and pasture management isgood, then WECs and targeted worming are recommended. This ensures those animals with a higher burden are treated, whilst those with low counts are not wormed unnecessarily. Note that a once yearly treatment for red worm larvae and tapeworm is still essential.

Not only are WECs a more cost effective means of ensuring the health of your horses, but they reduce the chance of parasites developing drug resistance. This wouldresult in wormers being partially effective or completely ineffective – a very concerning situation that is already developing (much like antibiotic resistance).

Pregnant and lactating mares and foals may only be treated with certain wormers. Discuss this with your veterinary surgeon and always follow manufacturer’s recommendations.

  • Any new horse/s on the premises should be wormed with a product that kills red worm larvae, tapeworm and roundworm. The animal should then be isolated for 2-3 days prior to turn out on grazing, to allow time for all the worms and larvae to be killed. 
  • Ensure every horse is dosed correctly according to their weight. Weigh tapes are available, or your veterinary clinic may have scales for a more accurate measurement. If you are in doubt ask you veterinary surgeon to advise you on your horse’s weight. 
  • Keep a record of which wormer was given to every horse and when it was administered, along with any WEC results. 
  • Talk to your veterinary surgeon about a plan for your premises. Ideally, review the system yearly, particularly if there are any major changes in yard management.
XLEquine worm managemen in horses3
                        XLEquine worm managemen in horses4  
  • Fenbendazole Will treat encysted small red worm larvae if used for 5 consecutive days, but some resistance reported. Will also treat large and small redworm and large round worm.
  • Pyrantel Can be used from 4 weeks old. Double dose will treat tapeworm. Also treats adult redworm and large roundworm. 
  • Ivermectin Treats most stages of redworm and roundworm. 
  • Moxidectin Treats encysted red worm larvae and roundworm. Not for use in foals <4months. 
  • Praziquantel Treats tapeworm only.
Prevntative healthcare is not a particularly sexy topic, but its something we believe all horse owners should invest in. It can of course, help reduce the risk of unexpected or significant vet bills, which can be associated with a sick horse. 
The trouble is that there are a huge variety of sources of information for you to access with the presence of the Internet, social media and other equine professionals. It can be quite confusing trying to unpick it all and truly identify what is best for your horse. 
We know, from a survey in Horse and Hound (April 2015) that horse owners are worried about troubling their equine vets with questions about basic healthcare or worry that they will be compelled to book and pay for a visit to get the information that they need. We want to reassure you that XLEquine vets are keen and able to help you with all and any questions you have about the health of your horse. Building a strong and loyal relationship enables us to better monitor what is ‘normal’ for your horse so we can pick up subtle signs of illness.

Look out for the Picture of Health activities which XLEquine practices will be undertaking through the Spring and Summer, offering a range of educational opportunities. Why not send us your photos of you and your horse looking a Picture of Health to This email address is being protected from spambots. You need JavaScript enabled to view it. ?

XLEquine currently has 35 members across the UK, ranging from large equine referral hospitals to mixed veterinary practices with an equine specialist component, incorporating over 120 equine vets. As a group of independently owned, progressive veterinary practices the XLEquine team work together sharing knowledge, experience and skills to deliver the highest quality equine care to their clients.
For further information on horse health issues, EquineSkills veterinary training for horseowners, and much more visit or follow us on facebook at

A-Z Horse Ailments - more articles helping you understand the many ailments your horse can suffer from Read more