sheep abortion
Approach to abortion
History | · How many abortions? · When are they aborting? – last 3w gestation = EAE, last 6w = campylobacter · Are the ewes systemically well? – D+, anorexia = salmonella · If lambs are alive, are they normal? – hairy little shakers = BDV, weak = campylobacter, normal = BDV · Previous history of abortions? · Poor conception/scanning? · Recent stressful events? · Management and nutritional status? Any recent changes? · Vaccination status? · Closed flock? Any new animals? |
Investigations | · Clinical exam of any ewes or lambs · Examine the placenta and aborted material o Placentitis + brown exudate – EAE o Grossly normal but dark cotyledons and necrosis – toxoplasma o Normal – salmonella o Mummified/stillborn foetus – toxoplasma · Collect samples to send to lab o Placenta, incl. >1 cotyledon – modified Zieh Nielson stain = EAE, PCR = toxoplasma, immunohistochemistry = toxoplasma, campylobacter o Foetal liver/spleen – virus isolation/PCR = BDV o Foetal stomach contents – gram smear or culture = salmonella, campylobacter o Foetal fluid (thoracic/abdo) – indirect fluorescent ab test = toxoplasma |
Management | · Immediate action o Isolate cases and mark ewes – don’t foster lambs onto these o Treat any systemic disease o Maintain good biosecurity and hygiene o Explain zoonotic risk to famer – EAE, toxoplasma · Long term control o EAE – vaccinate, 3w before tupping, purchase accredited disease free stock and keep separate until after 1st lambing § Can give oxytetracycline between day 90-126 of gestion to help maintain placenta o Toxoplasma – vaccinate, prevent transmission via direct host (keep cats out of feed stores) o Campylobacter – prevent feed/water contamination, no vaccination license o Salmonella – can use cow vaccine off license o Border disease – closed flock, test replacements, don’t mix pregnant ewes with cattle |
Causes | · EAE – ZOONOTIC o Chlamydia abortus – gram -ve intracellular bacteria o Spread via aborted material and veneral fluid o If infected before or during pregnancy = abortion in last 3w gestation o Clinical signs: placentitis (thick) and brown exudate · Toxoplasma o Protozoa – ZOONOTIC o Infected via ingestion of oocysts, shed in cat faeces (sheep = IH) o If infected § Non-pregnant = immunity § Pregnant = abortion, stillbirth, mummification, infertility o Clinical signs: grossly normal placenta, but dark cotyledons with areas of white necrosis · Campylobacter o Gram -ve bacteria o Transmission: via wildlife, carrier sheep, aborted material (NOT venereal spread) o If infected during pregnancy = abortion in 7-25d (usually last 6w gestation), then sheep develops immunity o Other clinical signs seen: D+, weak lambs · Salmonella o Spread via ingestion of aborted material or contaminated faeces o Clinical signs in ewes: D+, anorexia, sudden death o No lesions on foetus or placenta · Border disease o Pestivirus shed by PO o When infected § <60d gestation = foetal death or hairy little shakers § >85d gestation = normal foetus, born with ab |