Farmers should be alert for ill-thrift in animals as levels of chronic liver fluke disease in cattle and sheep peak in late winter/early spring, according to the February NADIS Parasite Forecast, sponsored by Merial Animal Health.
“Chronic disease due to liver fluke infection can affect finishing times and cost farmers money” says Fiona MacGillivray, Veterinary Health Advisor for Merial Animal Health, “With one in five bovine livers condemned by slaughterhouses due to fluke damage, farmers are advised to request details on condemnations to assess the level of fluke exposure amongst the herd and enable appropriate treatment.”
Checking for the presence of fluke eggs
in faeces should be considered where beef cattle are grazing potentially infected pasture over winter and did not receive an autumn flukicide treatment.
Not all sheep display the typical symptoms of chronic infestation, such as ‘bottle-jaw’, but many will experience significant weight loss. In areas of high fluke risk, most flocks will have already been treated with triclabendazole, for immature fluke; however it is important to reduce reliance on this drug.
“Good husbandry measures, such as use of ‘safe grazing’ at turnout and in mid-summer, and choosing alternative treatments for chronic fluke can help preserve the use of triclabendazole for acute cases of the disease in sheep,” says Fiona.
Nitroxynil (Trodax) and closantel are effective against immature fluke (7 weeks post infection) and should be used for the treatment of sub-acute and chronic fluke disease in cattle and sheep. Albendazole and oxylozanide are effective for adult fluke infection (from 12 weeks post infection) in spring.
Parasitic gastroenteritis (PGE) in store lambs and yearlings is likely throughout the winter, due to continuing mild weather. The risk is particularly high on paddocks which were heavily contaminated earlier in the year by grazing lambs. The risk to out-wintered animals can be assessed by monitoring pooled faecal egg counts and dosing accordingly.
The late spring in 2013 caused considerable production losses in young lambs from late-hatching roundworms when lambs were grazing. If the mild weather pattern continues, an early spring could result in a lower risk of nematodirosis in 2014. More details will be released on the level of disease risk when March meteorological data is available.