'How to' guide to worming horses

'How to' guide to worming horses

Make sure your worming programme is effective

Parasitic worms can seriously undermine the health and wellbeing of horses. Ensuring that your horse is not carrying a heavy burden is all part of a day to day health care plan. Now, with worms becoming resistant to some worming drugs, simply dosing all horses with routine wormers is not adequate.

To preserve existing wormers for the future, and create effective worming programmes, we need to use wormers only when they are needed and as part of a wider strategy. Here’s a step by step guide to ensuring you get the best from your wormers now - and in the future.

Look after your pasture

Most parasites release their eggs into the faeces of your horse. Deposited onto the pasture they will hatch and develop into infective larvae, ready to be ingested, starting the worm cycle over again. Any worming strategy, therefore, should start with pasture maintenance.

Pasture maintenance for worm control:

  • Avoid over-grazing
  • Avoid over-stocking
  • Rotate paddocks
  • 'Poo pick' at least twice a week
  • Cross graze with other species (ideally sheep) if possible

Routine testing, not routine worming

With 80% of parasites being carried in only 20% of horses, a targeted approach which considers each horse on an individual basis is needed. Routinely dosing all horses with the same wormers is no longer enough to give good worm control. Costly and ineffective it can, in itself, encourage the development of resistant worms. Routine testing - rather than routine worming – is simple to do and the results will help you and your SQP advisor to decide:

  • Which horses do, and do not, require worming
  • Which types of worms are present on your pastures
  • Which are the appropriate worming products to use
  • How to achieve the most cost-effective approach to worming
  • How to reduce unnecessary treatments
  • How to maintain the efficacy of wormers by only using them when needed
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Choosing the right test

Different tests are needed to detect the presence of different parasites:

The most appropriate test for parasites

Parasite, Faecal Egg Count, ELISA Blood Test, Other, Season most prominent Small redworms Large redworms Large roundworms Tapeworms Bots Encysted Small Redworm Larvae Lungworms Pinworms Season Key

A Faecal Egg Count By counting how many eggs are found within the faeces of your horse a FEC test (known as a worm count) can act as a good indicator of the level and type of intestinal parasites present. Some parasites, including encysted small redworm larvae, bots and pinworms are not apparent in a FEC and should be presumed present or diagnosed by clinical signs. Order your kit.

Tapeworm Tests Worm egg counts have never been reliable for identifying tapeworm problems in horses. Now a new, easy to use new saliva test that shows the presence of tapeworm in the gut is available from EquiSal also an ELISA blood test conducted via a vet will identify tapeworm burdens.

When to test – and worm if necessary

Regular testing will mean that you worm your horse only when he needs it. Discussing the results with your Countrywide SQP will ensure you choose the right wormer for the job. By killing egg laying adults and suppressing egg output, worming also reduces pasture contamination. Here’s a sample targeted worming programme for a mature, healthy horse, kept at low risk from worms:

Winter FEC (optional) + Worm for encysted Redworm
Spring FEC all horses. Worm any with a count of 200+ epg
Summer FEC all horses. Worm any with a count of 200+ epg
Autumn FEC all horses. Worm any with a count of 200+ epg
  • Horses have their droppings analysed for the number of eggs present and animals with more than 200 eggs per gramme of droppings are then wormed.
  • Worm for encysted redworm in the winter, even if counts are clear. These parasites can remain in the dormant larval stage for a long time within the horse before making their presence known as mature egg-laying adults
  • Test for tapeworm twice a year with a six month gap between tests

How Countrywide can help

All Countrywide Stores have highly qualified professionals known as SQPs (Suitable Qualified People) who receive regular training to keep them at the forefront of knowledge on equine worming. Find your local store

Our SQPs are able to recommend testing kits, and will be on hand to interpret the results, devise a worming programme if needed and offer good advice on pasture management and general worming health. Some top tips include:

  • Always dose your horse accurately according to weight
  • If possible weigh using a weigh bridge or ask your Countrywide SQP for a weigh tape and add 10% to the measurement.
  • Test new arrivals and worm if necessary, keeping new horses stabled for 48 hours after worming to ensure any eggs are passed before turning them out to avoid contamination to pasture
  • Worm pregnant mares before and after foaling
  • Don’t forget to monitor foals very regularly and worm as necessary
  • Keep a record of your worming programme
  • Always follow manufacturers’ recommendations

For further advice on worming your horse or pony please speak to your Countrywide SQP. If you would like Countrywide to remind you when your horse requires a worm count, please register your details to automatically sign up to this free service.

Bots

Bots are the larval stage of the bot fly Gasterophilus sp. These larvae are found adhering to the stomach lining. Bots cause a mild inflammation of the stomach.

Control

The removal of the larval stages in the late summer or winter will break the life cycle of this parasite. The Group 3 class of anthelmintic will effectively remove this infection.

Tapeworm

The adult tapeworm lives in the small intestine and caecum. The damage done to the intestine is not great as they feed of the contents of the food within the gut rather than off the horse itself. However they do attach themselves to the gut wall and may cause ulcers to develop. These ulcers may predispose the horse to the
development of colic, abscesses and other more serious gut conditions.

Control

As it is not possible to control the intermediate host, control of tapeworms is usually carried out after mite activity has reduced in the Autumn (October). Depending upon whether the horse is stabled or left at grass over the winter another treatment could
be carried out in April or July. Pyrantel and Praziquantel are currently the only drugs available to treat tapeworm infection in horses in the U.K.

Small Redworms

There are many species of worms which come under the classification of Cyathostomims (formerly Cyathostomes). The characteristic, apart from size, which differentiates them from the large Strongyles, is they migrate into the wall of the intestine
where they form small cysts. At the end of migration and the period of inhibition a mass emergence of larvae occurs and this can have serious implications for the animal. Diarrhoea, mucosal ulcers and bleeding, and colic are common signs.

Control

Prevention/reduction of the accumulation of inhibited larvae is one method which is used and this involves minimising reinfection either by regular use of an effective anthelmintic and by reducing pasture contamination by collecting the faeces of animals using the pasture.

Pinworm

Infection by this nematode is common but it is not a serious condition. The signs of the disease are an irritation of the skin surrounding the anus (perineum).

Control

The local irritation caused by the eggs can be alleviated by wiping away the eggs, however the infection is easily removed by a regular worming routine.

Lungworm

The lifecycle of this parasite is similar to that of the cattle lungworm. D arnfieldi is primarily a parasite of donkeys and horses become infected by sharing a pasture with them. In spite of carrying the infection, both donkeys and horses do not often
show signs of a respiratory infection, however the damage done by the adult parasites in the lungs may contribute to the development of chronic respiratory disease in later life.

Control

The regular use of avermectin or benzimidazole anthelmintics for gut roundworm infections will simultaneously reduce lungworm numbers.