Sheep organisations release advice amidst EAE vaccine shortage
SVS and SAGG say that it is not appropriate to use any routine prophylactic antibiotics to control abortion.
The Sheep Veterinary Society (SVS) and the Sheep Antibiotic Guardian Group (SAGG) have issued advice for veterinary surgeons and farmers, as they criticise the lack of enzootic abortion (EAE) vaccine.
The advice offers support to veterinary surgeons and farmers, who may now need to make difficult decisions during tupping season.
On encountering an aborting ewe, veterinary surgeons and farmers are first recommended to isolate the ewe from the rest of the flock. Samples can then be taken to identify which abortion agent might be responsible.
SVS and SAGG say that it is not appropriate to use any routine prophylactic antibiotics to control abortion. They say that antibiotics should only be used in late pregnancy if it is to protect other ewes from an outbreak, or used in a group of ewes following a confirmed laboratory EAE diagnosis the preceding year.
Where flocks have previously been regularly vaccinated against EAE, there will this year be a small number of unvaccinated replacement ewes. The risk to these ewes is low if the remainder of the flock is vaccinated, but they should be marked and vaccinated next year when they are not pregnant.
If flocks are at high risk of disease, due to a recent outbreak or EAE-shedding ewes, sheep could be treated with an inactivated vaccine (Inmeva; Hipra).
Two doses are necessary – the first dose at least five weeks before mating, and the second dose three weeks after the first. A further booster may then be needed within a year. The vaccine can be given safely during pregnancy, with efficacy proven in the mid trimester, but it is not recommended in the final month of pregnancy.
Alternatively, if unvaccinated ewes are confirmed by a laboratory to be at high risk of disease, they can be treated with a single injection of oxytetracycline (at 20mg/kg) between day 91 and 126 of pregnancy.
Groups with lambing spread across four to five weeks should be injected exactly three weeks before the first lamb is due.
Veterinary surgeons are advised to contact MSD Animal Health for more information.
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Joanne Webster, a professor of parasitic diseases at the RVC, has been elected as a Fellow of the Royal Society (FRS).
