Horse Worming Alternatives

Typically, horse wormers do not remove all the worm parasites from a horse, their purpose is simply to reduce the quantity of worms to an acceptable level, where they do not pose a threat to the horse's general health. By taking steps to reduce the level of parasites infecting your horse, you achieve much the same thing. This may allow you to reduce the frequency with which your horse is wormed.

  • Manure Removal. One way to reduce the number of worms in your horse is to regularly (e.g. twice a week) remove the manure from the horse's field. This is advantageous because many parasites reproduce by laying eggs in the intestine, which come out with the manure, subsequently hatching into larvae which infest horses grazing nearby. By removing the manure on a regular basis, you remove a large number of eggs and thereby reduce the quantity of worm larvae entering horses on the field.
  • Checking egg counts before worming. If you take a 'fresh' sample of manure (e.g. less than half a day old), this can be examined by your veternarian (or yourself, if you know how) to count the density of eggs. As the density of eggs is related to the number of egg-laying worms in the horse, this gives a rough indication of the extent to which the horse is infected with worms and thereby gives an indication if worming medication is required or not. The exceptions to this are tape worms (whose eggs can be difficult to detect in a standard manure egg count) and Cyathastomes (which can remain in the larvae state for years without laying eggs), so it may be advisable to treat for these specific worms once or twice a year even if there is no associated egg count. Although tape worm eggs are difficult to detect in manure, there is a blood test for tapeworms, which is an alternative detection method.
  • Mixed animals. In general, worms are species specific. So worms that infect horses do not infect other grazing animals such as sheep or goats, and vice versa. By mixing animals on a field, a portion of the eggs produced by worms infecting one species are harmlessly consumed by other species, reducing the rate of subsequent infections. An exception to this is lung worm (see worm types), which is typically contacted from donkeys.
  • Simultaneous Worming. Horses which are pastured together should be wormed at the same time (i.e. all on the same day) to minimize cross-infection from some horses (e.g. horses that have not been wormed and consequently are releasing a large number of worm eggs and larvae onto the pasture) to other horses.
  • Field Rotation. As the manure builds up on the fields, so does the associated worm population. Rotating the horses between different fields can take them away from an area high in eggs and larvae to an area which is much lower. The best time to rotate fields is 1-2 days after worming, so that the wormed horses can benefit from being in a field with a reduced egg/larvae population.
  • Harrow. A harrow is a farm implement, normally dragged behind a tractor, which is used to smooth a field. Driving it over the horse's pasture will break up and distribute the manure piles, exposing the eggs and larvae to the elements and thereby shortening their survival time on the pasture. This is most effective in hot and dry weather, where the sun and dehydration will kill the larvae and dry out the eggs,
  • Elevated Feeders. If the horses are fed in an area where they defecate ('shit'), the food (hay, grain) should be elevated off the ground to prevent eggs or larvae getting into it and infecting the horses with additional worms. Note that hay feeders should not be elevated too high, as horses are designer to eat near the ground; horses that are forced to eat much of their daily food at a high level can get jaw misalignment and other issues.
  • Clean boxes. Just as horses can contact eggs and larvae from manure on the field, they can be invested from eggs and larvae in their box, particularly if they eat food (or bedding) off the floor. When multiple horses share a large box, the risk of cross-infection is added to the problem. Two days after a wormer, some horse owners completely replace the bedding and disinfect the box in order to kill off any parasites there.
  • Immediately Worm New Horses. When adding a new horse to an existing herd, it is advisable to worm the horse as soon as it is added to the herd (or preferably one to two days before) to reduce the extent to which the new horse may infect the existing herd.
  • Avoid Over Stocking. Horses avoid grass with horse manure, in favor of eating grass without manure immediately nearby. This is a natural adaption, since most worms are spread through manure, so avoiding the immediate area greatly reduces the worm infection rate. In the case of mixed animals (see above), horses will avoid grass with horse manure but are much more willing to eat grass near the manure of other species, since the risk of worm infection from other species (e.g. goats, sheep) is low. However, if the pasture has very little grass left, the horses will be forced to eat the grass near horse manure, resulting in a more rapid and extensive infection by worms.
  • General Immunity. To a limited extent, a healthy horse with a good immune system will have more resistance to worms than an ill one. By keeping your horse in good condition, you provide some partial protection from the worming issues.
  • Bot Egg Removal. The Bot parasite (which is treated like a worm parasite but is in fact the larvae form of the Bot fly) lays its eggs on the coat of the horse. By removing the eggs (preferably daily) from the coat, one can greatly reduce this parasite. See Worm Guide for more details.
  • Herbal Solutions. There are a number of companies selling 'natural' wormers, using herbs (such as garlic) or homeopathic remedies. Some of these solutions may be effective for certain types of worms, providing an alternative to chemical wormers. However, as there is little reliable proof of their effectiveness, when using them it would be advisable to confirm their effectiveness afterwards (e.g. by doing an egg count, as discussed above). Furthermore, it appears that these natural remedies have little effect on eggs or larvae (being aimed mainly at the adult form), so more frequent worming may be required to keep the level of infection to acceptable levels.

For articles on other aspects of horse worming, see our Guide to Horse Worms, Worming and Wormers.