Campylobacter can cause late-term abortions in ewes

Campylobacter is a common bacteria that causes late-term abortion and still births in ewes. Occasionally an outbreak can lead to a devastating abortion storm causing up to 50% foetal loss. These occur several years apart, when a naïve (previously unexposed) group of ewes get exposure to the organism. However, research shows that less obvious lower-level losses are occurring yearly in maiden ewe and ewe lambs, causing marking percentage losses between 5-10% that effect the bottom line.

If tested, the majority of farms would test positive for at least one of the two known strains of Campylobacter that cause abortions, C. fetus fetus or C. jejuni. In the past it was regarded to be an issue of cooler, higher rainfall regions but it is being detected in drier, mixed farming and pastoral regions right across Australia. The bacteria survive best in cool, wet conditions so issues are more common when ewes are lambing in winter and spring.

Campylobacter is an oral infection. The majority of ewes will clear the infection and develop lifelong immunity. Some ewes however become chronic carriers, carrying bacteria in their intestine that are shed in their faeces and urine, contaminating pastures and water sources. Ewes ingest the bacteria, with some developing septicaemia, leading to infection of the placenta that spreads to the foetus. Infected foetuses may die and decompose inside the ewe, be stillborn, or born weak and struggle to survive after birth.

Can you detect Campylobacter carrier sheep?

There’s no way of detecting carrier sheep – most appear healthy and productive. Problem signs are noticed when there’s a large gap between scanning percentage and the number of lambs marked, especially in maiden ewes that haven’t developed immunity yet. You might also see a large gap between the marking in maidens and the rest of the flock. Other problem signs are ewes with brown vulva discharges or blood-stained breeches in late pregnancy, abortions and stillborn lambs, and weak lambs that die soon after birth. Occasionally ewes develop a significant uterine infection and will die or have reduced fertility in subsequent seasons.

How does it spread?

Infected ewes shed millions of bacteria for up to 6 weeks after aborting or giving birth, which presents a risk for other ewes. Birds and foxes can also carry Campylobacter if they’ve fed on infected, aborted foetuses and dead lambs. Collect and safely dispose of aborted foetuses, placenta and dead lambs, ensuring you don’t come into contact with infected material (causes gastroenteritis in humans).

Managing Campylobacter

Isolate affected ewes away from the main flock in an open, sunny paddock. Maintain good hygiene in the lead up to lambing, especially if ewes are containment fed in late pregnancy in cool wet weather, keeping water and feeders clean. Other risks are trail feeding pregnant ewes and intensive rotational grazing which bring ewes into close proximity, buying in replacement ewes with unknown disease status, and increasing length of time since the last exposure to Campylobacter (ewes have not had a chance for exposure to build resistance).

Managing the risk of Campylobacter

To manage the risk of Campylobacter causing abortions in your flock, vaccinate your first-time maiden ewes with Campyvax at ~$1.50/dose. Give 1st dose pre-joining and the 2nd dose 3-6 weeks later or when rams come out. Provide an annual booster to adult stud ewes. There’s no benefit to vaccinating already pregnant ewes in the face of an outbreak.

To investigate abortion in ewes, talk with your local vet. PCR tests using vaginal swabs, are cost-effective and fast, and can be used to check for other common infectious causes of abortion in ewes.

Are lamb loses an issue on your farm?

Consider Campylobacter if lamb losses are an issue, particularly in maiden ewes. Use pregnancy scanning to measure conception rates, and to provide a reference point to assess lamb marking percentages against. Vaccinating maiden ewes will be cheap insurance for their first lambing in colder, wet months.

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