Investigating Abortions in Cattle and Sheep
An abortion outbreak can be devastating to听a听flock听and/or听herd听and听poses听a potential health risk to humans.听Early听diagnosis is听vital听to prevent further spread and to minimise losses听in both the current and听subsequent听breeding seasons. Abortion rates higher than 2% are suggestive of an infectious cause and should be investigated.听Collection of听samples from听both听foetuses and placentas听are key to reaching a diagnosis.听听
Causes of听Abortion听听
Abortions can occur due to both infectious and non-infectious causes.听Injury听can lead to abortion.听To reduce听the听risk of this it is important to ensure there is adequate feeding space and that animals are handled gently in late pregnancy.听听
Ensuring adequate nutrition is also key. Conditions such as hypocalcaemia and twin lamb disease can lead听not only听to听the death of the dam but also听to still听births and abortions.听
Abortion rates higher than 2% are usually caused by infectious causes.听See below for听causes of abortion in sheep and cattle. Those listed in bold are the most common causes in Scotland.听
Causes of Ovine Abortion
- Chlamydia abortus causing enzootic abortion in ewes (EAE)
- Toxoplasma
- Campylobacter
- Salmonella species
- Listeria
- Schmallenberg virus
- Blue tongue virus
- Border disease virus
Causes of Bovine Abortion
- Bacillius licheniformis
- Salmonella species
- Trueperella pyogenes
- Neospora
- Listeria
- Campylobacter
- Infectious bovine rhinotracheitis (IBR)
- Bovine viral diarrhoea virus (BVD)
- Leptospira Hardjo
- Schmallenberg virus
- Blue tongue virus
When to听Investigate?听
Ideally every abortion or still birth should be investigated.听Your veterinary surgeon can听provide听specific advice relating to your flock/herd however investigation is听usually听warranted听in听the听following situations:听
- More than听2%听of dams abort/suffer stillbirths听听
- There听are multiple听abortions in a seven-day period听听
- Still听births and/or weak calves or lambs听are听born听
- Foetal deformities听are听present听听
It is a legal requirement to听report all听cattle abortions to the APHA within听24听hours. They will decide听if听statutory听testing听for Brucella听is听required. This testing is normally carried out by your own veterinary surgeon.听Their visit听provides the perfect听opportunity for听your vet听to take other samples to investigate听other听causes of abortion听listed in Table听2. There is no legal requirement to report sheep abortions.听
What听Samples听to听Take and听How?听
Care should be taken when handling aborted material as there is a risk of transmission of infection to humans. Gloves should be worn, and pregnant women must not handle abortive material. Both aborted foetuses and placentas should be collected and bagged. If you are unable to听submit听whole foetuses and placentas, whether听it鈥檚听a Holstein or a Hebridean, there are three key samples to collect:听听
- Foetal stomach contents听
- Foetal fluids听
- Placenta听
These samples allow all routine testing听required听to screen for the most common causes of infectious abortion to be carried out.听听
Samples can be听submitted听to your local听伊人直播 Veterinary Services PM Centre,听alternatively听your听own veterinary听surgeon can听undertake an abortion investigation听and听take samples.听Ovine or bovine abortion kits can be collected from your local 伊人直播 Veterinary Services PM Centre.听听听
Dam blood samples are worth collecting and can be stored pending foetal results.听听
What to Do听in the Event of听an Abortion Outbreak听
- Isolate aborted animals for at least one month听
- Reduce stocking density听
- Keep groups听static听
- Dispose of/collect aborted material and surrounding bedding听
- Be aware of the potential risk of infection to humans (especially children and pregnant women)听
Cause of Abortion Identified 鈥� What Do I Do?听听
Discuss the results of the abortion investigation with your veterinary surgeon. To limit the impact of certain diseases on听subsequent听breeding seasons, vaccinations may be recommended and must be administered appropriately and at the correct time.听听
Sometimes a cause of abortion is not听identified听this may be due to tissues being too autolytic (rotten) or inability to culture the organism. If abortions are still occurring submission of further听abortion听material is recommended. Remember听even if a cause is not found听many infectious causes will听have been excluded听providing useful information听on听what is听less likely听present in your flock/herd.听
Key听Points听
- Consider investigating every abortion,听if in doubt contact your vet听swiftly as听early investigation is key.听
- All cattle abortions should be reported to APHA within 24-hours.听听
- Collect both aborted foetus and placenta and store securely in a plastic bag.听
- Remember the potential infection risk to humans.听Wear听appropriate protective听clothing and ensure pregnant women and children are not exposed.听
- Discuss next steps with your vet. Early diagnosis can allow management changes which reduce losses in both current and听subsequent听breeding seasons.听
- To reduce risk of spread of infection isolate the dam and remove all aborted material and contaminated bedding.听
Lyn Gibson, Veterinary Investigation Officer, Lynn.Gibson@sruc.ac.uk
Posted by SAC Consulting on 17/02/2026
