Summer months 'to increase parasite risks'

As July is typically warm and sunny, the forecasts this year predict that unsettled weather will continue throughout the next month at least. According to new reports, this will have an effect on parasite levels in both sheep and cattle.

Wet summers have a knock on effect to parasite development on pastures; increased rainfall during the milder conditions can increase this threat, with the potential to deliver dangerously high levels of larvae.

A period of 10 days of dry conditions followed by wet weather is currently predicted to be a regular pattern in large areas of the country causing this increasingly high risk.

Lungworm cases in cattle are often detected in the months of June and July. Fiona MacGillivray of Merial Animal Health, sponsors of the NADIS Parasite Forecast, said: “The symptoms to look out for include increased breathing rate, coughing, a rapid loss of condition, reduction in milk yields, and even death in severe cases. Often the only indication of infection in adult dairy herds is a marked reduction in milk yield.

Lungworm should be treated as soon as possible after its onset and it is important to treat the whole herd.

“A suitable wormer can be used to control both lungworm and gutworms in youngstock. It is important that it provides persistent protection against re-infection with lungworm, allowing cattle to continue grazing pastures without risk of further disease for that period.” says Ms MacGillivray.

Liver Fluke from winter infection of snails in many areas will prove a risk this summer. In order to assess whether this will be a serious issue, high levels will be determined by the rainfall in June, July and August. The recent temperatures in May and June will have allowed some development of fluke eggs and the start of mud snail activity.

There is also a risk of blowfly strike in sheep which will continue throughout July and August in lambs, the risk for adult sheep is less likely due to shearing. However the choice of dip/pour-on preparation needs to be talked through with your vet due to meat withhold times.

Due to the increased confirmation of cases of Schmallenberg Virus (SBV), which has now been reported in all counties of the England and Wales with reports also coming in from areas of Scotland, "it is advisable to speak with your local vet on a preventative programme," NADIS, the Animal Disease Information Service said.

The National Farmers' Union have said they are writing to all its members urging them to assess if their livestock are at risk of contracting the Schmallenberg virus (SBV) this summer.

Spread by midges, SBV was first identified on German and Dutch farms in 2011 and has since spread throughout Europe with more than 1750 cases in the UK. Cases have been confirmed in Dumfries and Galloway and Aberdeenshire and there is the expectation that the virus will start to circulate more widely in Scotland in 2013. NFU Scotland, along with SRUC and Biobest, has a monitoring programme in place to help track the spread of SBV.

Exposure to SBV can result in relatively mild conditions in cattle and sheep but where infection takes place during the early stages of pregnancy (25-50 days in sheep, 70-120 days in cattle); it can result in congenital disorders of lambs and calves. Infection also causes a drop in milk production and may also be linked to poor breeding performance.