Schmallenberg vaccine could be in short supply

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Current stocks of Zulvac® SBV, the vaccine for Schmallenberg Virus (SBV) have a sell by date of July 2018 and the availability of new stock is still uncertain. The fact that AFBI has now reported the disease in sheep in all six counties of Northern Ireland has sparked interest in vaccination, which has to be administered prior to the breeding season.

Aurelie Moralis, Veterinary Consultant with Zoetis, points out that the disease is spread in the summer months by the Culicoides midges, which are widely present across Europe and move easily between farms and regions allowing rapid and extensive spread of infection. However it is often not until calving or lambing that the disease is discovered.

The disease can affect cattle and sheep and veterinary advice is where possible protection by vaccination prior to the breeding season plus an effective insecticide against the Culicoides midge such as the deltamethrin in Fly & Lice Spot On™ in the spring, summer and autumn months.

Zulvac® SBV is the only vaccine licensed for Schmallenberg and beef or dairy farmers planning to breed cattle over the next few months could protect their animals from this virus which is so unpredictable.

Zulvac® SBV is licensed for active immunisation of cattle and sheep from 3.5 months of age to reduce viraemia associated with infection of SBV. Cattle require two doses given three weeks apart every 12 months, whereas female breeding sheep require only one dose given at least 14 days prior to breeding.

One farmer reported showering ewes a number of times during pregnancy in an attempt to control the vector but still ended up losing a lot of lambs.

Commenting on this treatment Aurelie said: “Whilst vector control methods are an important part of a Schmallenberg Virus control strategy, and will certainly be useful at farm level, alone they are unlikely to be successful at controlling disease over a large area, because of the behaviour and movements of the midges. Therefore vaccination alongside an effective insecticide is the most effective way to protect your flock/ herd against SBV.”

There have been some suggestions that mixing this year’s breeding ewe lambs with mature females as early in the season as possible will help protect the ewe lambs by exposing them before they become pregnant, but Aurelie strongly advises against this.

She added: “Mixing older ewes with younger ones will not ensure exposure as there is no direct transmission from one sheep to another. Without vaccination, the only hope is that the naïve ewe lambs get bitten by an SBV infected carrier midge. Mixing them with older ewes will not increase the chance of this happening in any way.”