Agriculture Reference
In-Depth Information
During an outbreak of EAE, giving tetracycline (300 to 500 mg per head
per day) is helpful in bringing the situation under control. If more than one
ewe aborts, this should be started immediately and continued until test
results come back. Also, because EAE is contagious, aborting ewes should be
removed and strictly quarantined for 30 days. Bedding from quarantine pens
should be burned.
Vibriosis
Campylobacter fetus
and
Campylobacter jejuni
are the bacteria that cause vibrio-
sis, the second-most-common cause of abortion in North American fl ocks.
These bacteria, which live in the gallbladder and intestine of the ewe, invade
the uterus, placenta, and fetus during late pregnancy. When they are intro-
duced to a clean fl ock, 90 percent of the ewes lose their lambs, but once
that has happened, the ewes become immune to the bacteria and won't abort
again. However, they can be carriers that contaminate the feed and water,
thereby infecting other ewes.
Ewes can be vaccinated at the beginning of the breeding season and then
again about 90 days later. Once vaccinated, they require one annual booster
shot. Your veterinarian may recommend tetracycline or a penicillin prepara-
tion for treating ewes in a newly infected fl ock.
Toxoplasmosis
Toxoplasmosis is caused by a microscopic protozoan (coccidium) whose natu-
ral host is a cat. Other species, including sheep and humans, can become an
unnatural host to this organism when it “gets lost” in its normal migratory
route. This parasite invades many tissues, causing infections in the brain,
eyes, uterus, fetal membranes, and the fetus itself. Clinical signs are consis-
tent with the particular tissue that has been damaged. Abortion and stillbirth
are most commonly observed. Infection occurs when cats defecate, leaving
the infectious organisms on hay, grain, and other food consumed by sheep.
Ground-up grain is a common target because it constitutes a ready-made litter
box. There is no vaccine or effective treatment for sheep, though farm cats
can be treated. Stray cats should be removed immediately. Strict sanitation;
clean, uncontaminated water; dry, protected storage of hay and grain; and off-
the-ground feeding troughs reduce the incidence and spread of disease.
