Internal parasites, otherwise known as worms, if left untreated can result in death!

All horses have some form of worm burden.  If not managed, or left untreated can cause anaemia, colic, loss of condition and even death.  A horse can be infected by more than one variety of worm at any one time. 

A horse with a worm burden will be forever hungry, with the food not being utilised correctly which will directly affect the ability of the horse to do the job required; it is also a waste of money.  A large number of colic cases are as a result of worm infestation.   There are a variety of worming programmes available with excellent advice and information on how best to manage your horse's worming programme to help ensure and happy, healthy horse.

Unfortunately it is not possible to have a horse 100% free of worms.  Horses at grass will  have worms, a fact of life.  We can however, control the worm burden to manageable levels, reducing the impact on the horse.

Types of worms

Large red worm (Strongylus vulgaris) Small red worm Roundworm Tapeworm Pinworm Lung worm Stomach worm

Bots are laid by the gadfly and are not a worm.

Symptoms of a horse infested with worms

Large appetite but fails to put on or maintain condition Poor topline and large belly Little energy and may be anaemic (anaemia will be confirmed by blood tests taken by your vet) Dull coat, staring to look at Skin feels dry and tight Loose droppings, or even diarrhoea, usually foul smelling Colic

Note:  It is important that all horses and ponies are on a suitable worming programme. It is possible for a horse to have a serious worm infestation without any visible signs!  If you think your horse has a worm problem, contact your vet at once.

What is a worm count?

This is a means of measuring the number of eggs per gram.  It is taken from a dung sample which is then sent off to a laboratory for analysis.  The count can vary from fifty thousand to tens of thousands of eggs.  A large egg count would suggest a large number of female, adult worms.  A low egg count gives an indication of that day only; this could rise drastically during the forthcoming weeks.

Life Cycle

A warm, moist environment is an ideal breeding ground.  In these conditions eggs are able to lie dormant for many months before hatching. Spring to early autumn is the optimum time for hatching and development.  Dry, cold weather will have an adverse effect on the larvae, killing large numbers.  The  first stage is hatching, with warmth and moisture they moult to become second and third stage.  Depending upon the time of year will depend on how long it takes to get from stage one to stage 3.  During stages 1 and 2,  if eaten by the horse will be digested, no harm done.  Stage 3, if not eaten within a few days will die.  All worms (stage 3) penetrate the mucosal  lining of the gut; they moult again to become fourth stage.  Eventually they leave the gut and migrate to the bowel, growing into adult males and egg laying females.

It is of paramount importance that horses, ponies and donkeys are wormed on a regular basis, especially those at grass.  It is wise to speak with your vet or specialist to agree how to proceed. Worms can develop a resistance to various drugs and it is important you are up-to-date with the latest thinking and products available.  Failure to do so is detrimental to your horse and a waste of money; speak to the experts.

Young animals, foals, have low immunity and it is essential they are wormed in accordance with veterinary advice from an early age.  Failure to do this may result in stunted growth, health and performance issues during their lives and even death!

Manage your grazing

Grass is the most natural feed for horses and also the commonest access to worms.  Collecting and removing droppings to promote clean grazing is a must.  Your muck heap should be far enough away from your paddocks the worms can't migrate back.  Ideally droppings should be picked up daily; at the very least weekly.   Rotating and resting paddocks for several months, taking hay off the paddock all help reduce the risk of infestation and allow the grass to recover.  Grazing with cows is a good way of managing the control of worms; sheep are also good.

New horse onto the yard New horses brought onto the yard should be wormed before being turned out with other horses.  It is important they are wormed then kept in for 72 hours to ensure all worms have passed through before having access to the .  An untreated horse can quickly contaminate pasture.  Currently there is nothing you can treat the land with to kill eggs and larvae, the only effective way is to follow a worming programme.

Methods of dosing

Powder, granules and pellets are all added to the feed. Dosing syringe with a paste or gel