Agriculture Reference
In-Depth Information
The left side of a bloated sheep blows up like a balloon; the sheep goes off
feed and acts very uncomfortable. Prevention is the best medicine: feed dry
hay before turning the sheep onto lush pasture.
Grass Tetany
Grass tetany is a nutritional disease that results from a defi ciency of magne-
sium. Affected animals (often lactating ewes) avoid the rest of the fl ock, walk
with a stiff and unnatural gait, and quit eating. They may appear nervous,
twitch or stagger around, or frequently lie down and get back up. In the late
stages, an animal lies fl at on its side and pedals its legs at the air; its breathing
becomes labored, which is followed by convulsions and death.
Grass tetany is seen most often in areas that have low levels of magnesium
in the soil and is worse if the area also has high levels of potassium or nitrates.
Your county Extension agent can advise you on magnesium levels in your
area. The disease is less likely to be seen in sheep grazing pasture that has a
good mix of legumes in with the grass, because these deep-rooted plants help
to bring up magnesium within the soil matrix. It is also much more common
in animals that are in poor body condition than in those that are in good con-
dition with an adequate overall plain of nutrition.
The recommended treatment is 50 to 100 mL of a 50 percent saturated
magnesium sulfate solution injected subcutaneously. For prevention, shep-
herds in areas where grass tetany may be a problem should provide a high-
magnesium, trace mineral, salt mixture.
Diseases Caused by Viruses
Several disorders in sheep are caused by viruses. Aside from ovine progressive
pneumonia, most of these disorders are not often fatal in full-grown sheep;
however, bluetongue can be fatal in lambs, and soremouth has zoonotic
potential — in other words, it can be transmitted from animals to humans.
Bluetongue
Gnats carry the virus that causes bluetongue. This disorder occurs in warm,
wet weather, when the gnats are out. Affected sheep develop a high fever and
infl ammation of the mucous membranes. Subsequent signs include ulcer-
ations around the lips, tongue, and dental pad and crusty discharges from the
nose. Though generally not deadly in mature sheep, it causes birth defects
in a high percentage of lambs if the ewes have the disease during pregnancy.
Because it is a viral infection, it must run its course, but your veterinarian
might prescribe antibiotics to stave off secondary infections.
