A shortage of EAE vaccine: what sheep farmers need to know

By Megan Fergusson – Veterinary Investigation Officer

Sheep farmers are likely already aware of the issues with the availability of the Enzootic Abortion (EAE) vaccine prior to this tupping season. This shortage could lead to difficulties for some flocks next lambing season. The impact of this vaccine shortage will vary depending on individual flock circumstances. Here’s some advice from the Sheep Veterinary Society, Sheep Antibiotic Guardian Group, and SRUC Vet Services.

Managing the Shortage

For flocks that have previously vaccinated all stock with no recent outbreaks of EAE, the ‘at risk’ group will be the hogg or gimmer group that may have to enter the breeding flock without vaccinal cover. A practical decision may be to not breed the hogg group this year. However, if they are to enter the breeding flock, ideally, they should be lambed separately from older ewes. This group should be marked to ensure they are vaccinated pre-tupping next year when the vaccine becomes available.

Recent EAE Outbreaks

For flocks with recent EAE outbreaks, the vaccine shortage may prove to be more problematic. There is an inactivated vaccine (Inmeva; Hipra) that may be appropriate for use in your flock. This vaccine requires two doses: one at least 5 weeks pre-tupping and a second dose 3 weeks after the first, which can be given during pregnancy. A yearly booster is required to maintain immunity if using this vaccine.

Prophylactic Antibiotics

Historically, prophylactic antibiotics were used in the control of EAE outbreaks. While this is no longer appropriate as a blanket approach, it may be applicable to groups within the flock where a positive laboratory diagnosis of EAE has been made. In these cases, a single injection of oxytetracycline (at 20mg/kg) between day 91 and day 126 of pregnancy may be used as part of a control plan. For groups with lambing spread over a 4 to 5 week period, this means injecting them exactly 3 weeks before the first ewe is due to lamb. This should be discussed carefully with your vet and only used in the face of a confirmed diagnosis.

Buying New Breeding Stock

If buying in new breeding stock this autumn, please consider your flock status and the status of those being bought in.

Control of Abortions

Previous advice on control of abortions remains:

• Aborted ewes should be isolated from the rest of the flock.
• Take steps to investigate the cause of abortion; foetus and placenta are required for a full investigation. Please collect these in a sealed bag or glove and contact your vet. Note that the placenta is particularly essential to diagnose EAE.
• Mark any lambs that are twinned onto ewes that aborted or had weak/dead lambs and do not retain these as breeding replacements.

Please contact your vet to discuss the most appropriate actions for your flock.

Posted by SRUC Veterinary Services on 12/09/2024