Horse Worming

How do I worm my horse?
As the information on equine worming can be complex (see the page Parasite Control in Horses) it can be difficult to decide how and when to worm your horse.
This problem is simplified if we consider different age groups and the horse's environment and also the desirability of using antparasitic drugs in cases where they may not be totally necessary. This unecessary usage is expensive, potentially detrimental to the horse and ultimately can lead to uncontrolled resistance in the worm population whereby no wormers work. This situation can be put off as long as possible by responsible worming which has a good chance of saving you money too!

Pregnant Mares and Foals
Pregnant mares should be wormed thoughout their gestation with suitable equine wormer and a final dose given 2-4 weeks prior to the foal being due.
The foals themselves should be wormed as they start grazing and this should be repeated in their first year again with a suitable equine wormer at manufacturer's recommended intervals. Tapeworm infection is less likely in horses less than two months of age so a narrow spectrum wormer is suitable at this point.

Adult Horses over 3yrs
Many inaccuracies are often quoted with regards worming programmes in adult horses. These include that tapeworm need treated for twice yearly, that only young and old horses need to be treated for cyathostomes and that all horses need regular roundworm treatment. The facts of the matter are very different and are often surprising to people who have wormed their horses religiously in the past (to the obvious benefit of the wormer manufacturers and their shareholders!).
These facts are:

  • horses in the UK only need to be treated for tapeworm once a year (there is no evidence to support twice yearly tapeworm treatments being necessary)
  • all horses should be treated for cyathostomins in the winter to prevent accumulation of encysted worms in the gut wall
  • on average 80% of horses do not need regular roundworm treatments as their burden is so so low that worming makes no difference to the horse but only promotes resistance in the roundworm population as a whole

Horses up until 3 years old tend to have higher roundworm and tapeworm infestations than older horses (until they get to 15-20 years) and so these youngstock are more likely to need regular worming based on the results of faecal egg counts.
The only extra advice is that any treatment given should alternate year to year to avoid the problem of resistance occuring.

So we get to this outline for worming an adult horse:
Worm against tapeworm (Double dose Strongid P or Pyratape P one year, Equimax or Eqvalan Duo the next year)

Mid June
Collect faeces from every horse and check roundworm output by faecal egg count. 80% of horses on average will not need wormed. If they dont move to the Winter worming for Cyathostomins. If they do need wormed against roundworm then use a usually effective product (Eraquel, Eqvalan, Strongid P, Pyratape) but always follow up with a repeat worm egg count 2 weeks later to ensure the product used is actually working. Without this follow up egg count the product may already be ineffective and the money spent on it is 100% wasted.

Protect against cyathostomins with Equest or similar one year and a 5 day course of Panacur Equine Guard the next year.

Stomach Bots
Bots are the larval form of certain flies (Gasterophilus spp.) which attach themselves to the stomach lining and can in thankfully rare cases cause stomach ulceration and even perforations with devestating consequences. Modern equine wormers of the avermectin family (eg Eraquell and Equimax) will kill Bots so removing this problem.

For the latest prices on equine wormers and faceal egg counts as standalone items or in conjunction with a yearly booster or vaccination course please contact us.