The number of positive liver fluke cases is beginning to rise following a wet, mild summer and autumn, with farmers now facing 'high challenges' in some areas.
Results of testing and post-mortem examinations in recent weeks suggest liver fluke activity in early autumn was still quite low.
However, the number of positive cases is now increasing and industry groups SCOPS and COWS are urging farmers to keep up with testing to avoid being caught out.
They explained that the forecast predicts a medium to high risk on the west coast, all the way from north Wales up to northern Scotland.
However, unpredictable weather patterns mean it is likely snail habitats, and therefore liver fluke will be more widespread – and the window for infection more prolonged – than in previous dry summers.
Therefore, the industry bodies are urging farmers across the country to 'stay on their guard and keep testing'.
Speaking on behalf of SCOPS, independent sheep consultant Lesley Stubbings said there were particular concerns about those farmers who had treated sheep already.
"Flukicides do not have any residual effect, which means a dose given too early offers no protection if sheep have been put back onto infected pastures.
"It is vital to establish if fluke is present – so treatment can be given at the right time," she explained.
Highlighting the importance of testing, Dr Philip Skuce of Moredun added: “The coproantigen test can detect the presence of liver fluke a little earlier than faecal egg detection, which is particularly useful when the risk is considered high on a farm.
"But as we head into December, faecal egg count testing methods are likely to be most appropriate, particularly post-housing.”
Rebecca Mearns, of Biobest, warned of the potential perils of over-use of flukicides, in particular closantel.
She said: “We are concerned about reports that sheep farmers are repeatedly treating sheep with closantel against Haemonchus contortus (the barber’s pole worm).
"Dosing at intervals of less than six weeks risks adverse effects in sheep, including blindness. If farmers then also use the same drug to treat liver fluke, the risks of overdosing are even higher.
"This risk is made worse because some producers have assumed they have resistance to triclabendazole, ruling out the use of this potentially useful flukicide on their farm.
"Talk to your vet about how you can confirm the position rather than jumping to conclusions," Ms Mearns said.
