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Are you over worming your horse?

With the use of regular faecal egg counts you could drastically reduce the amount of wormers you give your horse.

Why worm?
Worming is carried out because a large worm burden can cause:

1. An increased frequency of colic.
2. Ill-thrift and weight loss.
3. Enteritis (inflammation of the gut wall) and diarrhoea

Common problems with worming regimes

Resistance
Resistance to a wormer means that the drug given does not kill the target worm. At the moment resistance is on the increase. This means that in the future you can’t rely on certain drugs to kill some worms. This will leave no option but to accept a higher rate of disease and rely on management only to reduce burdens.

Overdosing / underdosing
Often horses are dosed too frequently. For example dosing with Equest at the same intervals as dosing with Eqvalan. This is totally unnecessary and means that resistance will develop quicker in your population of horses.
Underdosing will also cause an increase in resistance. If you can, get a “weight tape-measure” these are not very accurate but often more accurate than the eye of the observer.

Rotation
Rotation of wormers has traditionally been used to prevent resistance problems, but of the four classes of wormer:

• One has wide-spread resistance already.
• One must always be used to treat tapeworm.
• One must always be used to treat encysted redworm.

This leaves one class of wormer, which you are able to rotate!!

Diagnosis
It has always been difficult in the past to advise about worming because of the difficulty of diagnosing worm problems.
We are now using faecal egg counts to monitor roundworm burdens and blood tests to monitor tapeworm burdens.

Non-compliance!
This is mainly a problem in yards where horses are owned by different owners. Owners either treat their horses at different times or do not treat at all. The risk to your horses is obvious. Get a yard worming policy and make sure owners stick to it.

Control of parasites
Now for the bit you’ve all been waiting for so pay attention from now on!
There are two ways to control worms:

- Management
- Using drugs

Management

• “Poo-picking”!
  This is by far the most effective way to control worms. It should be done at least twice a week, but daily is best. This should start when the temperature increases in the spring and can stop after the first few frosts in the autumn.
• Do not over-stock.
• Graze with other species e.g. sheep.
• Do not chain harrow the fields when the weather is warm and wet i.e. especially not early spring as this simply spreads the eggs around.
• Graze young horses and those with high egg counts separately.

Use of drugs
As already stated the use of worming drugs is surrounded by problems.
By far the best way to treat is by targeted dosing. This involves regular faecal egg counts (FEC) and treatment of horses only with a worm count above a certain level. The advantage of this is that it will probably reduce your worming costs. It will slow down the development of resistance and you will be using less drugs on your horse.

Follow the five point plan!

1. Carry out faecal egg counts every 3 months from the spring, to end of autumn. (Once you know the patterns of infection you can increase this to every 6 months.) Faecal egg counts can be carried out by us. Please bring a small handful of faeces in a plastic bag, labelled with your name, address and the horse’s name. Don’t forget fresher is better!! So try to collect in the morning and drop them straight in.
2. Only worm your horses if the faecal egg count is over 200 eggs per gram of faeces.
3. In the autumn all susceptible horses must be dosed with Panacur Guard or Equest. Otherwise dosing is not necessary if routine faecal egg counts and pasture management are carried out. Susceptible horses are those younger than 7 years old and older than 25 years old including horses in high risk populations.
4. New horses should be dosed with Panacur Guard or Equest on arrival.
5. Routine dosing for tapeworm should be carried out at least once a year where blood tests are not carried out. If you want to carry out the blood-tests (advisable) then combine this with a visit, or a yard visit to reduce the cost.

Some common wormers available:

For further information, please visit http://www.diagnosteq.co.uk/