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The November 2022 Liver Fluke Forecast collated by the Department of Agriculture in collaboration with Met Éireann, UCD, Teagasc and Animal Health Ireland predicts infection being prevalent in the west and northwest with occasional losses in the midlands, east Munster and north Leinster.
The forecast highlights that May was wet in the northwest and dry in the south while June was also wetter in the west than the rest of country, giving rise to a higher risk.
The forecast also highlights the importance of selecting a product that targets the stage of liver fluke parasites likely to be presenting the greatest threat. It states that “for sheep, a drug effective against early immature as well as late immature and mature flukes should be used to protect against acute disease. In addition, sheep should be moved from affected pasture to prevent re-infection.”
The duration between treatments will depend on the risk profile, taking in to account the history of issues on the farm. The traditional recommendation for outwintered sheep was to administer treatment in November, January and April.
On farms where issues with liver fluke were serious, the recommended treatment time in cases is reduced to every four to six weeks.
Decisions on such a treatment plan should be taken in consultation with your vet to ensure that treatment is definitely warranted as with such a short duration between treatments there is a significant risk of resistance developing.
Product choice and alternating between active ingredients is critical in reducing the rate of resistance developing. Accurately estimating the liveweight of sheep and administering the correct volume is also vital in this regard.
Faecal egg counts can play a role in determining the level of infection as the liver fluke risk season progresses, with the main threat changing from acute to sub-acute and then chronic liver fluke. All possible information sources should also be utilised including following up on the health status of livers in slaughtered sheep and submitting any cases of mortality where there is not a straightforward cause detected for laboratory analysis.
This week’s focus supplement outlines the requirements of the ram action in the new Sheep Improvement Scheme. The final terms and conditions of the scheme have also clarified the parasite control action. This was stated as a faecal egg count reduction test in the initial document released but has since being clarified as a faecal egg count.
Under the action, participants with lowland flocks must collect and submit two faecal egg counts each year between 1 June and 30 September, while hill sheep flocks must carry out one faecal egg count within four weeks of lambs being weaned. The action is aimed at identifying the worm burden and making informed treatment decisions.
A number of farmers have also made contact in the last week with concerns that flocks which scan in January will not be in a position to select the pregnancy scanning action. This is due to the fact the first year of the scheme starts on 1 February and runs to 31 December while year two starts on 1 January 2023. It is probable that the Department will provide a mechanism to overcome the transition in to the new scheme and this will be clarified online or in next week’s edition.
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