Spring Worming
by Helen Barnes BSc (Hons) DMM DipM MCIM,
Fort Dodge Animal Health.

Spring and rising temperatures sees the development of worm eggs, which were dormant on pastures, into infective larvae. In addition egg output from your horse increases with previously ingested larvae developing into egg producing adults. It is, therefore, now time to start planning your horse's worm control programme for the forthcoming year.

The objective of any worm control programme is to prevent worms completing their life cycle, whilst protecting the health of your horse.

It is, however, during this time of year that if your horse was not treated in the winter with a single dose of moxidectin (EQUEST) or 5-day course of fenbendazole for the control of encysted small redworm, that it may now suffer the consequences. Encysted larvae hidden the gut wall of your horse, if left untreated, will typically emerge en masse in the spring. Potentially fatal this emergence may result in diarrhoea, rapid and severe weight loss, or colic, requiring urgent veterinary attention.

Spring Worming Treatments:
	Routine Roundworm Control: Routinely treat against roundworm. Dosing intervals based on active ingredient, i.e. moxidectin every 13 weeks, ivermectin every 8-10 weeks or pyrantel every 4-8 weeks. When planning your routine worm control it is important not to use wormers against which there is known resistance. With resistance to both benzimidazole1 and pyrantel2 based wormers these should only be used following guidance from your vet.
Additional treatments to be added if not covered as part of routine treatment. Dependent on active ingredient used for routine roundworm control.
	Tapeworms: Treatment for tapeworm is recommended every 6 months3, with a treatment due in the spring in March/April. Control of tapeworm traditionally involved a double-dose of a pyrantel-based wormer, however in more recent years, praziquantel based wormers that specifically target tapeworm (i.e. EQUITAPE) have become available for use in horses.

Spring Worming Tips:

· As horses are now spending more time on pasture this is an optimum time to 'spring clean' stables. However, in order to help reduce horses' exposure to re-infection, regular cleaning should be carried out throughout the year to remove hardy worm eggs that can survive for many years within stables and to reduce mites, the intermediate host of tapeworms.

· Pasture should not be 'over crowded'/'over stocked'. Ideally fields should contain no more than one or two horses per acre, as horses lower down the pecking order will be forced to graze the rough pasture where worm burdens will be higher.

1. Fisher MA et al. Veterinary Record (1992) 130: 315-318.
2. Coles GC et al. Veterinary Record (1999) 145: 408.
3. Proudman CJ et al. Veterinary Record (1995) 137: 45-49.

For further information on worming plus a free worming calendar, call the EQUEST/EQUITAPE literature hotline on 01489 774232 or
Email: equest-uk@fdah.com

Information kindly provided by Fort Dodge For Further information visit:- www.wormingyourhorse.info