Infectious Causes of Abortions in Sheep
Expect an infectious cause if >2% of flock aborts.
Diagnosis of abortions
- Submit fetal tissues, blood from dam, placenta.
Best management practices
Isolate all aborting females.
Improve nutrition to all.
Be sure all feeders are elevated.
Treat females with tetracycline if warranted under veterinary care.
Completely dispose of all materials associated with aborted births and normal births, including dead lambs by incineration or land fill.
More than one agent or cause may be active at one time.
Chlamydiosis-EAE Enzootic Abortion of Ewes
Caused by Chlamydophila abortus
Acquired at birth, from aborting ewes, intestinal carriers and venereal spread.
Will abort at next pregnancy.
Abort in last two to four weeks of pregnancy.
Fetus can be fresh, autolyzed, or weak alive.
Vaccine available, flock treatment available. Consult with veterinarian.
- Caused by Campylobacter fetus or C. jejunum
- Spread by carrier ewes in endemic flock and possibly by birds.
- Abort last 4-6 weeks
- Fetus will be autolyzed. Placenta will be normal.
- Vaccine available.
- Caused by Toxoplasma gondii
- Ingestion of oocysts of parasite in cat [kitten] feces.
- Abort any stage of pregnancy.
- Mummification-think toxo first.
- Mummification, resorption, stillbirths, infected weak lambs.
- Placenta will have white 1-3 mm foci in cotyledons.
- Can use serology to diagnose.
- Caused by Listeria monocytogenes
- Likes cold and dark to grow. Grows in spoiled silage.
- Fetus is septicemic
- Causes retained placenta and metritis.
- Caused by any Salmonella species
- Causes abortion, stillbirths, weak neonates.
- Ewe will be sick. May die.
- Caused by Coxiella burnetii
- Organism can be shed in placenta and birth fluids at normal parturition
- Causes abortion in the last 2-4 weeks
- Fetus will be autolyzed
- Placenta will be thick.
- Can be treated with antibiotics.
- Caused by Brucella ovis
- Usually causes ram epididymitis
- Causes a few abortions, stillbirths and weak lambs.
- Have about 20% smaller lamb crop.
- Results in longer lambing period.
- Causes placentitis.
- Caused by Leptospira species
- Can be in urine contaminated water or food.
- Causes late gestation abortions with autolyzed fetuses.
- Causes nephritis, hemoglobinuria in the ewe.
- Also agalactia and infertility.
- Caused by Sarcocystis sporocysts in canine feces.
- Aborting ewe is clinically ill.
Cache Valley Abortion
Caused by Bunyanviruses
Has Culicoides and mosquito vectors
Causes abortions, mummifications, arthrogryposis, hydrancephaly, December and January lambings.
Can diagnose with serology
This material taken from Dr. Mary Smith's Infectious Abortions in Sheep and Goats - Sheep and Goat Medicine - 2014.