Flock Health

Ovine Abortion
With the festive season behind us it means many of you will be starting lambing – unfortunately as always this means you may also start seeing abortions. Everyone is likely to experience a couple of sporadic cases but if levels exceed 2% of the flock then an infectious cause is more likely and you should contact us and consider investigation.

In any abortion case the following action should be taken:
• Remove any aborted lambs, afterbirth and contaminated bedding ASAP. Thoroughly disinfect the area
• Make a note of the ear tag of the affected ewe to ensure the following are both done properly:
- Isolate her – she should remain in isolation for at least 3 weeks and until all vaginal discharges have ceased
- Do not use these ewes as foster mothers for any ewe lambs that may be used for breeding
• Contact us to discuss if treatment is required or if we should start investigations – when submitting samples to the laboratory it is important that both the lambs AND afterbirth are sent for the best chance of a diagnosis
- Currently there is free of charge testing for Schmallenberg virus – please contact the surgery if you get any deformed foetuses and we can advise you further

The 3 most common causes of abortion we experience are:
Enzootic Abortion

Caused by Chlamydophila abortus – affected ewes are generally well and just show a red/brown vulval discharge, lambs are often freshly dead or weak and die despite supportive care. It is highly contagious and is spread from ewe to ewe or directly to their lambs. The bacteria is in any aborted material and afterbirth and is shed by the ewe for about 3 weeks following abortion, it can survive in the environment for up to 6 weeks. Infected ewes will generally abort during the next lambing period (unless they are more than 6 weeks from lambing at the time). Any ewe lambs exposed will abort in their first year.
Enzootic abortion can be readily vaccinated against; in the face of an outbreak whole flock administration of oxytetracycline can be considered – please contact the surgery for further advice if you think this may be necessary.

Toxoplasma is spread primarily in cat faeces which can contaminate pasture and feed. A stable cat population on farm is fine as it will keep away other cats and control vermin but you should try to minimise access to feed stores. If the parasite is ingested by ewes during mid pregnancy they will abort, if exposed earlier on it can lead to early embryonic loss and high barren rates at scanning. There is no ewe to ewe spread and once infected a ewe will then become immune meaning it is more commonly seen in younger ewes.
Again there is a vaccine available.

Several Campylobacter species can cause abortion – it is spread in the faeces of birds and rodents but also by carrier sheep. It is more common in intensive systems and where there is poor hygiene. Affected sheep can be well or can also be off colour and/or scouring. There is no real treatment option as the bacteria has often spread widely before the first cases are seen but it is particularly important to isolate those affected. Once infected ewes are then immune to further challenge and will not abort again. A vaccine is not readily available in the UK but can in some circumstances be imported under a special licence.
Finally please remember some of these are also transmissible to people and pregnant women should stay away from sheep, and avoid any contact with any excretions, during lambing.

With reference from NADIS

Related SEV Branch