There are still farms reporting problems with chronic fluke in sheep despite the relatively low incidence of fluke last winter, warn experts.
Whilst the UK may be on lockdown due to Covid-19, livestock farmers are warned that liver fluke is carrying on as normal.
Despite the relatively mild winter, average temperatures have generally remained below 10 degrees Celsius from December 2019 to March 2020.
The development of fluke on pasture will have slowed or even stopped during this period, according to Sustainable Control of Parasites in Sheep (SCOPS) and Control of Cattle Parasites Sustainably (COWS).
Followed by a warm April, also one of the driest on record, snail activity and subsequent fluke development on pastures will also have been low this spring.
However, farmers are urged by the two groups to not become complacent about the risk of fluke later in the season.
Moyna Richey of the Animal and Plant Health Agency (APHA) said: “It is wise to test adult stock now to determine the need for any treatment to limit pasture contamination for the rest of the year."
“Across the APHA network this winter and early spring we saw a small number of cases where chronic fluke caused issues in pregnant ewes.
"In addition, we detected fluke eggs in faecal samples from sheep on farms in Wales and the South West of England.”
With temperatures beginning to rise into the summer, the top priority now is preventing contamination of pastures with fluke eggs, SCOPS and COWS explained.
A single adult fluke can produce thousands of eggs in one day meaning infected stock could be shedding large numbers of eggs.
If farmers haven’t treated this spring they are being urged to talk to their vets about checking livestock.
SCOPS and COWS advice for farmers
• Screen using faecal egg counts (FEC)- collect samples from 10 sheep or cattle, bag separately. They will be combined by the lab into a single composite for counting.
• Screen using a copro-antigen test - collect samples from 6-10 sheep or cattle, bag separately. They will be tested individually by the lab.
• Fallen or dead stock are also very useful to check for fluke.
• Bulk Milk Tank monitoring - useful for dairy herds. Quarterly or monthly monitoring can help assess fluke exposure in cows and testing your herd now will provide a base line value and help identify when/if levels of exposure begin to rise later in the year.
"With the current virus restrictions, it is important to remember that sample collection and submission may be affected," both groups said.
"Before you begin sampling, check with your veterinary practice about any changes to their usual sample submission and testing procedures.
"For example, if you are submitting samples by post, consider any delays and check which day the recommend you post samples."
Most of the liver fluke inside animals at this time of year affect adults, so treatment with a product that targets adult fluke only is recommended.
Products containing albendazole, oxyclozanide (or clorsulon in cattle) are effective adulticides.
"For albendazole, remember that the dose rate for fluke is higher than that used for roundworms, so check the instructions," SCOPS and COWS said.