Abortions
As we approach lambing time we are confronted with the occasional or sometimes the true abortion storms.
- What do we do?
- How do we approach the problem?
Diagnosis
We must first diagnose the problem before we can have a chance at stopping the abortions. The success of making a diagnosis is proportional to the quality of the sample delivered to the laboratory. It is important that both the placenta and the fetus be presented in as fresh a state a possible. Diagnosing abortions is a numbers game. The more samples submitted the better the chance of a diagnosis.
When an abortion occurs:
- 1. Place the fetus and membranes in a plastic bag and get it to the laboratory immediately.
- 2. If you are not submitting the fetus to the laboratory bury or burn the fetus, membranes and any soiled bedding or feed. Make certain that other ewes do not have access to contaminated bedding, feed or water.
- 3. Abortion storms (numerous abortions near lambing time) - Although many organisms can cause abortion, there are three that cause the majority of the problems: Campylobacter, Chlamydia and Toxoplasma.
What to do before the diagnosis comes back from the laboratory
Medicate the entire flock with LA200 or Tylan 200.
Consult your local Veterinarian for specific details.
Preventing Abortions
SANITATION : Do not feed on the ground. Keep feed and water free from contamination of placental membranes and fluids. Remember, no bacteria or virus has developed a resistance to good sanitation.
VACCINATIONS : vaccines are available for campylobacter and chlamydia. Our recommendation is to use these separately as they have different incubation periods. Keep in mind that all vaccinations take the initial dose followed by a booster in about 10-14 days, then an annual booster. Chlamydia needs to be given prior to breeding. Campylobacter boosters are probably more effective given the last 1/3 of gestation. To give the lamb protection, through the colostrum, from Clostridial infections, the clostridial vaccines can be given at the same time with the Campylobacter. If E.coli and roto/corona are annual scours problems, the ewes can be vaccinated at this time with these products.
Consult your local veterinarian on the availability of products and their use in your flock.
Toxoplasma Abortions
Toxoplasmosis is caused by a protozoan parasite that infects most species of warm-blooded animals, including birds and man,throughout the world. The causative agent is Toxoplasma gondii. The parasite has a rather complicated life cycle which includes rodents and cats. When placed in the sheep's environment, it will cause abortions. Members of the cat family are the only definitive host of the Toxoplasma organism and, therefore, serve as the main reservoir. Cats become infected early in life and develop an immunity after shedding the organism for about 20 days. This fact is important in the control of the disease in sheep. The disease is transmitted to sheep via contaminated feed or water. Barn cats, using the feed bin or bunk for a liter box, are a common source of contamination. In sheep, the abortions happen in late pregnancy from the disruption of blood flow through the placenta to the fetus. This causes necrosis of the placental attachment (cotyledons) resulting in death of the fetus with resorption, mummification, maceration of the aborted fetus or stillborn and weak lambs. The ewes do not appear ill and recover from the abortion quickly. The ewe develops a lifetime immunity.
Diagnosis
If your flock has a history of abortions, the telltale sign that it's Toxoplasma abortions is that the cotyledons are red to tan-colored with white pinpoint areas of calcification. For definitive diagnosis, take both fetus and placenta to the diagnostic laboratory. In a large flock, more feti and placentas taken to the laboratory will result in a quicker diagnosis.
Treatment
There is no treatment in sheep.
Prevention
Since cats are the primary reservoir of the Toxoplasma organism, prevention is directed at controlling the cats. Infected kittens develop an immunity and cease shedding organisms after about 20 days.
Some producers neuter their cats to maintain an adult population as it is the young cats that spread the organism. Partial control of the problem in sheep has been reported by the use of 15mg/head/day of Rumensin in the feed on a daily basis. This must be started prior to exposure. Rumensin is not approved for use in sheep in the US.
CAUTIONS: This disease is transmissible to humans. Pregnant women are at a very high risk as the organism can pass through the placenta to the fetus and may cause birth defects or mental retardation. Cats are the main source of the organism but abortions from sheep also are a source of human infection. Pregnant women should be especially cautious of exposure from sheep at lambing time or contact with cats. The organism can live in the environment for up one year, therefore, cats can contaminate the garden, the flower bed or other places. Sanitation is the main prevention.
Prepared by Cleon V. Kimberling, Gerilyn A. Parsons, Jay Parsons, and Wayne Cunningham
Optimal Livestock Services, LLC
970-231-2477
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