Secondly, if cattle are to graze on-farm the following year, effective flukicide
treatment over winter will ensure that the cattle are not shedding fluke eggs in their dung onto pasture after turnout and will not contaminate pastures," said Dr Forbes.
As well as ensuring maximum productivity, flukicide
treatments over winter will ensure that pasture are not contaminated the following year.
Out-wintered stock in some areas may require additional doses of flukicide
if wet conditions persist, including a spring treatment against adult fluke to reduce the shedding of eggs to infect snails over the subsequent summer.
Unfortunately, no flukicide
can repair liver damage.
Dr Vickers said: "Cattle rarely show signs of acute fluke disease, therefore unless acute disease is suspected or diagnosed, a flukicide
with activity against late immature/adult fluke stages (closantel, clorsulon, nitroxynil) may be selected, especially for treatments given in the late autumn/winter months.
NADIS said that stock should be dosed with a flukicide
around eight to 12 weeks after turnout to reduce the release of eggs from cattle infected already.
The research found the best long-term strategy is to use flukicides
in rotation, ensuring parasites do not come in contact with just one flukicide
She said that where fluke is confirmed, all ages of grazed cattle should be treated with a specific flukicide
Unless acute disease is suspected or diagnosed in cattle, a flukicide
that acts against late immature and adult fluke stages should be selected, such as closantel, clorsulon or nitroxynil, for treatment in the autumn and winter months.
She advised farmers to monitor flocks for signs of the disease and treat with an appropriate flukicide
Infected cattle can be treated with a flukicide
, preferably in consultation with a veterinarian for optimum treatment timing and success.
The challenge from high levels of liver fluke on pasture continued throughout the first two months of 2013, and many farmers seem unaware that if sheep are put back on high risk pastures they will need to be re-treated with a flukicide
five to six weeks later to avoid losses.