The overall risk of liver fluke infection in cattle and sheep this winter will be high across all areas of Northern Ireland, the Agri-Food and Biosciences Institute (AFBI) has said.
Rainfall levels in June, July and September were considerably higher than the national average.
Unusually high rainfall has kept ground conditions damp, which AFBI said is ideal for the intermediate host of liver fluke, the snail Galba truncatula.
In areas which are poorly drained and remain wet all year round, multiplication of snails will have continued and AFBI expects the likelihood of liver fluke infection in the autumn and winter to be particularly high.
Types of Liver Fluke
Liver fluke disease can occur in either acute or chronic forms AFBI advises, with the chronic form being the most common.
The acute form occurs in sheep and is caused by the migration of large numbers of immature flukes through the liver, this form can often be fatal and has serious welfare implications.
Symptoms of a severe infection include distended painful abdomen, anaemia and sudden death, while in less severe cases poor production and growth, coupled with reduced appetite and abdominal pain, are apparent.
Fluke infection can cause a reduction of 5-15% in the milk yield of dairy cows and loss of growth in fattening lambs and cattle, representing considerable financial losses, it said.
AFBI advises all farmers to review their fluke control measures at this time of year, while minimising access to snail habitats (wet and poorly drained areas).
At this time of year, it is recommended that farmers use a dosing product that is effective against immature and mature forms of liver fluke.
It is advisable to use such a product on out-wintered sheep once or twice in autumn and maybe in January, coupled with a treatment effective against adult flukes in early spring.
However, farmers need to be aware that resistance to fluke treatments is an emerging problem and has been detected in Northern Ireland, AFBI has said.
The effectiveness of treatments on individual farms can be checked by taking dung samples three-four weeks after treatment and submitting them, through your veterinary surgeon, for laboratory examination.
Stomach or Rumen Fluke
In recent years, stomach or rumen flukes have also become common in sheep and cattle in the North.
It is understood that the snail Galba truncatula serves as intermediate host to both liver fluke and rumen fluke.
Adult rumen flukes are less damaging to sheep and cattle than liver flukes, however heavy infections of immature worms may cause diarrhoea, ill-thrift and, possibly death in young animals.
AFBI advises farmers who suspect that a stomach fluke infection may be a problem on their farm to contact their veterinary surgeon to arrange for appropriate laboratory testing, and to discuss treatment options.