Agriculture Reference
In-Depth Information
can run rampant through a fl ock. The good thing is that
D. nodosus
can only
live out of a sheep's foot for about 2 weeks, so if you keep sheep off a pasture
for 2 weeks, the organisms will die off in the soil. The bad thing is that some
sheep can act as carriers of foot rot, constantly reinfecting the soil that other
sheep walk on. Quarantining new animals for 2 weeks is the best way to stop
foot rot from being introduced to a foot rot-free fl ock.
D. nodosus
is an anaerobe, which means it grows in an oxygen-free environ-
ment, deep in the hoof tissue. This is why hoof trimming is an important part
of foot rot treatment, so that dead tissue is removed and oxygen can enter.
Foot rot starts with a reddening of the skin between the toes of the hoof.
Odor is faint or absent in the beginning but becomes noticeable as the infec-
tion worsens. Infection begins in the soft horny tissue between the toes of
the hoof, or on the ball of the heel, and spreads to the inner hoof wall. As the
disease progresses, the surface of the tissue between the underrun horn has a
slimy appearance. The horny tissue of the claws becomes partly detached, and
the separation of the hoof wall from the underlying tissue lets the claw become
misshapen and deformed. There is relatively little soft-tissue swelling.
In severe infections, it is often more practical to dispose of the most seri-
ously affected animals and concentrate treatment on the milder cases. Use
the following steps to treat for foot rot:
1.
Trim the hooves, removing as much of the affected part as possible.
Disinfect the knife after each hoof, and burn the hoof trimmings.
2.
After trimming, have sheep walk through a footbath prepared with zinc
sulfate.
3.
Hold the sheep on a dry yard or pasture for 24 hours, if possible.
4.
Vaccinate (see Vaccines and Other Biologicals, starting on page 234).
Foot Scald
Foot scald is sometimes mistaken for foot rot. It involves the soft tissue
between and above the toes and the “heel,” usually on only one foot. Hooves
with this disorder have infl amed, moist tissue and sometimes open sores.
Foot scald is very similar to athlete's foot in humans.
Causes of the disorder are dampness, wet pastures, prolonged walking in
mud, or abrasion caused by dirt or foreign objects lodged between the toes. It
occurs primarily during wet periods, and the condition sometimes improves
without treatment in dry weather. Foot scald is a major problem only because
it lessens the foot's resistance to more-serious disease, such as abscess or foot
rot, and causes sheep to eat poorly and not get enough exercise.
