Agriculture Reference
In-Depth Information
areas if possible. Snail-destroying chemicals are available but must be used
with caution: most of these chemicals contain copper sulfate, which would
poison the pasture for the sheep. In addition, they cannot be used in areas that
drain into water inhabited by fi sh or water that humans or livestock use for
drinking.
As with other parasites, liver fl ukes cause loss of body condition, diarrhea,
weakness, potbelly, bottle jaw, and often death. Liver-fl uke infection can be
diagnosed accurately in the liver of a slaughtered sheep and can sometimes
be diagnosed by microscopic examination of feces.
Coccidiosis.
Coccidia are microscopic protozoan parasites that are present
in most fl ocks, but they rarely cause problems.
It once was believed that each species of animal had its own type of
coccidia and that crossinfestation did not happen. Later experiments have
proved that some types of coccidia are transmissible to different animal spe-
cies, which act as intermediate hosts. When coccidia-infested muscle tissue
(or even intestinal tissue) was fed raw to dogs, they became infected and
passed sporocysts. However, cooking or freezing apparently renders these
CAUSES AND PREVENTION
OF COCCIDIOSIS
Outbreaks of coccidiosis happen mainly in 1- to 3-month-old feedlot
lambs being raised in crowded conditions other than in the pasture
arrangement of a farm fl ock. Any rapid change of feed ration may
predispose the lambs to coccidiosis, which usually appears within
3 weeks of the time they are brought into the feedlot. Other factors
are chilling, shipping fatigue, and interruption of feeding during
shipping.
Small amounts of coccidial oocysts may be found in most
mature sheep, but these sheep develop immunity, so they seldom
show symptoms of infestation. However, they can contaminate their
surroundings, and then weak lambs become infected. To prevent
this, lambs should be fed during shipping and should not have their
ration changed too abruptly from grass to concentrated feed. Over-
crowding and contamination of feed and water must be prevented,
for these are the main sources of infection.
