Equine worming protocol

Equine worming protocol

In order to conserve our current efficient equine wormers we need to act responsibly.
ALWAYS USE THE CORRECT DOSEAGE. If in doubt get a weigh tape.
There are currently 3 basic classes of equine wormers for treatment of Roundworms.
1 – Benzomidales or ‘white drenches’ e.g. Panacur, Telmin
2 – Pyrantel – Strongid P or Pyratape
3 – Avermectins – e.g. Eqvalan, Panomec,Vectin,Noromectin Also includes Equest(Moxidectin)
NO SINGLE CLASS TREATS THE RISKS FROM ALL ROUNDWORMS/ TAPEWORMS &
BOTS. However Equest praemox combines moxidectin for roundworm treatment+ bot +inhibited
cyathostomes along with Praziquantel to treat tapeworms.

Each product has a different interdosing interval.
In a group of horses all kept under the same management there will be those individuals that are very
susceptible to worms and those that are inherently resistant. By taking regular faeces samples of
individual horses an owners vet can build up a picture of the relative sensitivity to worms for each
horse. This knowledge can allow a longer inter dosing interval for some horses thereby prolonging the
effectiveness of the wormers and limiting resistance. Young horses less than 4 years of age are
relatively susceptible to worms and so require more worming. Aged horses or those that are sickly have
poorer immunity and so harbour more worms which produce a greater level of pasture contamination.
Where horses grazing together are owned by different people it is essential that all parties treat their
horses together as a grazing group and with the same wormer/group.
If faeces can be removed from pastures twice weekly then the pasture worm burden is reduced
twenty fold!

Appropriate harrowing of pastures in dry weather breaks up the faeces and allows them to dry up
thereby killing the worm larvae. In hot weather worm larvae are hyperactive and use up energy
resources much quicker. If done in wet weather the harrowing process distributes the worm larvae from
the roughs to the lawns and increases the risk to the horse!
Essentially use one wormer group per grazing season. However as we need to treat certain worm types
on a strategic basis e.g.Tapeworms in late April and late September, Bots in winter,so we have to
compromise this ideal. Eradication is not possible, we aim for control and to minimise clinical disease
as a result of these parasites.
Basic programme, (Ideal for youngstock)

Year 1
Equest every 13 weeks (or Ivermectin product every 10 weeks) with Equitape given in late April and
late September to control Tapeworms ( or substitute Equest Praemox but not for foals). NB – Equest
not to be used in foals ( use Eqvalan for foals).


Year 2
Panacur type given every 8 weeks. With a 5 day course in late March and early December to control
encysted stages. Also a Double dose of Strongid P or Pyratape P given in late April and late September
to control Tapeworms. When giving these tapeworm doses as these products also control Roundworms
they can be substituted for a Panacur dose. Bots need to be controlled by a separate product in late
December e.g. Eqvalan.
Year 3
Strongid P or Pyratape P every 6 weeks with a Double dose of Strongid P or Pyratape P given in late
April and late September to control Tapeworms. With a 5 day course of Panacur in late March and
early December to control encysted stages. Bots need to be controlled by a separate product in late
December e.g. Eqvalan.
Other considerations
If horses are housed overwinter and have no access to grazing then they cannot pick up any worms.
Hence no further treatments are needed until the spring about 3-5 weeks after turnout.
As above if pasture faeces removal is practised then worm egg counts are likely to allow less frequent
wormer dosing because of this extra information for your vet.
Mixed grazing with cattle or sheep will help limit the pasture worm burden as the eat the equine worms
which ends the life cycle. i.e. They act as biological worm Hoovers!
There is only one species of roundworm common to Cattle, Sheep & Horses and currently it is not
thought to be a risk to horses.
Mixed grazing therefore reduces the risk to the horse and so can extend interdosing intervals. Monitor
by worm egg counts during the grazing season remembering that each grazing season is subtlety
different.
There is no point using worm egg counts (WEC) to monitor infection levels for tapeworms but a blood
test is available. Inhibited worms do not lay eggs so WEC are useless to monitor Larval
Cyathostomyasis. Do not take a sample immediately after worming. Taking one at the time of worming
and about 2 weeks later can check for wormer resistance.
Remember Foals & Yearlings are more susceptible due to lower natural resistance so must be treated
more aggressively.

Source: http://www.northparkvets.co.uk/equine_worming_protocol.pdf