The risk of Liver fluke infection is hjigh this year and early treatment will make for a better winter and easier lambing time.
Liver fluke when left untreated can and has in the past resulted in the death of sheep. It is vitally important that farmers can spot signs of the disease as early as possible so treatments can be started without delay.
Liver Fluke is caused by the trematode parasite, Fasciola hepatica. It can affect both cattle and sheep. It is mainly influenced by the climate, with milder winters and wet summers leading to an increased risk year after year.
Other minor causes include increased stock movement, intensification of farming and triclabendazole resistance. Disease in animals is caused when the flukes migrate through the animal’s body and burrow into the liver tissues or when adult flukes find their way onto bile ducts of the liver, causing inflammation.
The fluke cycle involves two separate hosts, the mud snail and cattle/sheep.
Both host must be present for the flukes cycle to continue. The snail is usually found on wet farmlands in areas with poor drainage. The snail host is known for its rapid reproduction rates, they can produce up to 100,000 eggs in just 3-4 months. This increases the risk for sheep farmers and their stock.
In sheep live fluke disease can have three stages:
Acute- Leads to sudden death.
Subacute- leads to anaemia and causes rapid weight loss.
Chronic – this causes long term weight loss and again anaemia.
There are many ways to spot the signs of Liver Fluke, and to be frank, the earlier the better.
The majority of fluke infections in sheep are present as acute liver disease, compared to subacute or chronic in cattle.
Acute: Acute infections can usually be observed in Autumn/ early Winter. Clinical signs include a reduced weight in animals caused by reduced grazing, Sudden death happens in up to 10% of instances. Infected lambs can lose up to 30% of their weight gain. Fluke numbers are in the thousands in this stage, although these are immature and means no eggs can be found in an animals faeces.
Subacute: Subacute infections occur usually in winter months. They result in rapid weight loss and a reduced physical condition in animals. Lower fleece quality can also be observed along with lower lambing percentages and fertility in animals. Fluke numbers in this stage are approximately 500-1,000, and eggs can be observed in your animals faeces if infected.
Chronic: This stage usually occurs in Summer, or Winter. Numbers of fluke are around the 200+ range with all flukes in their adult phase. Eggs in faeces will be observed if the animal is infected.
Signs of this stage in an animal include, continued weight loss, poor body condition and bottle jaw. This means your sheep could die in an emaciated state, and this occurs more often if the sheep is in the late stages of pregnancy or early lactation. This obviously can mean a farmer losing both ewe and lamb, whilst lamb birth weights may be reduced by more than 5%.
There are many different treatments (anthelmintic) available for Liver Fluke in local co-ops and veterinary practices, although which to use is down to what stage of fluke is infecting the animal. The repeated use of the same products can also lead to flukes developing and resisting the treatment, as a virus would in humans.
The department of agriculture usually advises the treatment for liver fluke to be carried out in November, January and again in April. Although treatment may be required as often as every 7-8weeks depending on your farms history with the disease. It is advised to consult your vet when choosing a treatment or devising a prevention programme.
When treating in Autumn/Winter, the dosing should be directed at all stages of the disease. Late in the winter, once animals are housed, the treatment can be directed more at the mature stages of fluke. It is therefore vital that farmers study their animals daily to help narrow down which stage the infection is in.
If possible to help prevent the disease, farmers should avoid wet farmlands where possible. Or if that’s not feasible an effort should be made to drain the land. It is advised, after treatment, that farmers should also place sheep back onto the dirty pastures for a couple of days before moving them on to new pastures. Farmers should make a conscious effort to avoid placing lambs on the same pastures where last year’s lambs would have grazed, and the same with older sheep.
Prevention and precautions are as vital as treatment to stopping the spreading of this parasite.
Although it might take more work in the short term, farmers if keeping a close eye on their stock, would save themselves a lot of future hard work and potential heartbreak. Don’t let Irelands interchangeable weather fool you or keep you off guard. Stay Vigilant and keep your animals fit and healthy for another year.