Parasite forecast

Parasite forecast



We recommend that any outwintered cattle should be treated with a flukicide as soon as possible.  Due to the wet autumn/winter period there could be significant numbers of fresh fluke eggs present on your pasture through February and March which will have re-infected your cattle even if they were treated last year.

Housed cattle – depending on the type of flukicide used in the autumn there may be some risk of overwintered fluke causing a problem in the cow.  This can be checked by looking for fluke eggs within the faeces.  We would recommend taking a few samples from individual cows particularly those that are thin to assess your risk.

Symptoms of fluke in cattle are usually most obvious between February and April.  Any cattle looking poor at this time of year should be considered at risk.


In most years sheep only pick up low levels of fluke from the pasture in March; however, this year has been particularly wet, and until recently we have not experienced many hard frosts which would normally reduce fluke numbers over the winter.  Fresh infection is also possible at this time of year and so if you are concerned about thin ewes we would recommend treating with an appropriate flukicide at this time of year.

It is important to carry out a post mortem examination on any dead stock to assess your level of risk.  Faecal egg counts are also valuable.


Another way of preventing fluke infection in your stock is eliminating the secondary host which is the water snail.  As the name suggests this snail requires water so if you are grazing any land which is marshy these areas should be fenced off or drained.

Animals should not be allowed to drink from ponds or ditches. They should be given fresh, clean water.  Smallholders might consider keeping foraging ducks which will eat the water snail.



Housed cattle are not at risk of picking up new infection from pasture.  Ostertagiosis is the biggest concern although cases of this are often seen after a dry summer (which was not the case last year!!)

Lungworm control needs to be considered on pasture where it has proved to be a problem before, vaccination with ‘huskvac’ is a successful means of control and should be done before turn out.


Nematodirus – the cold temperatures seen in December, January and February mean that we are likely to have a late hatch of nematodirus on the pasture this year.  This means that the main lambing crop is likely to be at risk.  The most likely time of year to see a problem will be May/June.

Prevention measures consist of trying to avoid grazing ewes and lambs on pasture that stocked pre-weaned lambs last year.  If this is not possible then prophylactic targeted treatment will be necessary, more information on this will be available once we have a more up to date forecast.

Parasitic Gastroenteritis (PGE) – Due to the relaxation of immunity in the ewes at lambing time, high levels of worm eggs can be dropped onto pasture.  To try to avoid pasture contamination for this years lambs we would advise either:

  1. Use a short acting anthelmintic pre turn out onto clean pasture (ie pasture not grazed last year)
  2. If turning out onto contaminated pasture use a longer acting anthelmintic
  3. Try to target treatment at ewes that will be under the most pressure, ie. First time lambers, those rearing twins or triplets and any thin ewes.

Selectively dosing the ewes in this fashion will help to reduce the risk of anthelmintic resistance developing.  The risk of PGE this year depends on the forecast which will be published soon.



Coccidiosis is normally a problem in calves 3 weeks – 6 months of age.  Cases are generally seen in the warmer summer months, so we would expect a low incidence at this time of year.  Good hygiene and avoiding overstocking is the key to prevention.

Coccidiosis can be diagnosed at the same time as a faecal egg count, if present then treatment with an oral drench is most appropriate.


This is normally seen in young lambs and in contrast to calves March and April is the time of year when most cases are seen.  Good hygiene and reducing stock rates are very important in preventing infection.

If there is a problem in the lambing sheds then in feed coccidiostats can be fed to pregnant ewes and lambs.  Treatment of clinical cases normally consists of an oral drench.

Symptoms to look out for are dull, scouring, poor doing lambs.