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COLLECTION: GOAT HANDBOOK
ORIGIN: United States
DATE INCLUDED: June 1992
Extension Goat Handbook
This material was contributed from
collections at the National Agricultural Library.
However, users should direct all inquires about the
contents to authors or originating agencies.
DOCN 000000019
NO B-13
CHEVRES FOR GOURMET
G. F. W. Haenlein; U. of Delaware, Newark
D. L. Ace; Pennsylvania State U., University Park.
Management and Housing
DOCN 000000060
NO G-6
COCCIDIOSIS
M. C. Smith; Cornell U., Ithaca, NY
S. B. Guss; Pennsylvania State U., University Park
Health and Disease Management
1 Coccidiosis is a contagious disease of goats, especially
young kids, throughout the world. The disease is caused
by one or more of approximately 12 different species
of protozoa, called Eimeria, which parasitize and
destroy cells lining the intestinal tract of the goat.
Sheep are also very susceptible to coccidiosis, but
even though the sheep forms may share the same names
with goat coccidia, many parasitologists believe that
the disease cannot be spread from goats to sheep or
from sheep to goats.
2 An infected goat sheds thousands
of microscopic coccidial oocysts in its feces every
day. When first passed, the oocysts are harmless to
another goat. However, under favorable conditions
of warmth and mositure, each oocyst matures (sporulates)
in 1 to 3 days to form 8 infective sporozoites. If
a young kid swallows the sporulated oocyst, the sporozoites
are released and rapidly penetrate the intestinal
cells. From here on, the life cycle gets very complicated.
The coccidia pass through several periods of multiplication
during which large schizonts are formed. The intestinal
cell of the goat is destroyed and thousands of small
forms called merozoites break out and invade other
intestinal cells. Eventually sexual stages are reached
and new oocysts are produced. The entire life cycle
from oocyst to new oocyst takes 2-3 weeks.
3 If a young kid is suddenly exposed
to many sporulated oocysts, it may become severely
ill 1-2 weeks later. It will be off feed, listless,
and weak. It may show abdominal pain by crying or
getting up again as soon as it lies down. At first,
the kid might have a fever, but later the body temperature
is normal or even below normal. Diarrhea begins pastey,
then becomes watery. The kid may dehydrate rapidly.
Contrary to various reports written by people more
accustomed to calves than kids, the diarrhea is only
rarely bloody. Neither is straining common. Signs
often show 2-3 weeks after the kids are weaned, because
the lactic acid produced by the digestion of milk
helps to inhibit occidia in the nursing kid.
4 Young kids may be killed quickly
by a severe attack of coccidiosis. Others - those
initially stronger or less heavily infected - will
develop a chronic disease characterized by intermittent
diarrhea and poor growth. Tails and hocks are dirty.
The kid with chronic coccidiosis cannot digest its
feed properly because the intestines have been severely
damaged. As a consequence, such a kid will be a potbellied
poor-doer for months afterwards. Frequently, such
a stunted kid will be too small to breed it's first
winter.
5 Even though coccidiosis is typically
a disease of the young growing kid, most adults are
mildly infected and continuously shed oocysts which
serve to infect young kids. Occasionally an adult
goat shows temporary diarrhea when stressed or exposed
to a new species of coccidia. This is especially common
after the doe has been boarded on another farm for
breeding.
6 Diagnosis of coccidiosis can be
based on clinical signs or microscopic fecal exams.
Coccidiosis is so common that it should be suspected
whenever kids older than about 2 weeks of age are
scouring. Sudden dietary changes can also cause diarrhea,
but these make the kid more susceptible to coccidiosis.
Thus diarrhea that begins with the consumption of
too much milk, grain, or lush grass may drag on for
days because of coccidiosis. Older kids and adults
with diarrhea may have worms rather than coccidiosis,
or they may have both problems together. Oocysts can
be identified if the feces are mixed with a concentrated
sugar solution. The oocysts float to the top, along
with larger worm eggs. They are collected and examined
with a microscope. Oocysts may be shed in the feces
as early as 10 days after a kid is infected, but often
the first attack of diarrhea occurs before oocysts
are available to be identified. In these cases, the
trained technician can do a direct fecal smear to
look for smaller merozoites, which do not float in
the sugar solution.
7 If a kid dies of coccidiosis, post-mortem
examination will quickly give the diagnosis. The small
intestine will have many irregular raised white areas,
often about 1/8 to 1/4 inch in diameter. A smear taken
from these white spots will show many coccidial forms
if examined under a microscope.
8 Whether or not a goat gets sick
with coccidiosis depends on several factors. One is
the number of oocysts swallowed at one time. Small
exposures, frequently repeated, lead to immunity.
Large exposures destroy all the intestinal cells at
one time and kill the kid. The age of the goat is
also important. This is partly because the older animal
has usually had time to develop some immunity. Also,
very young kids are more fragile creatures. Good nutrition
(including vitamin E-selenium supplementation in selenium
deficient areas) helps the goat to defend itself against
coccidiosis. Immunity to coccidiosis is rarely complete.
This means that the healthy adult goat continues to
pass many oocysts in her fecal pellets. However, most
of her intestinal cells are safe from invading coccidia.
As each of the 12 or so coccidia species is completely
independent from the others, with no cross immunity,
a goat that is happily living with one type of coccidia
may develop diarrhea when exposed to a different type.
9 Prevention of coccidiosis is very
important in larger herds if young kids are to thrive.
Once diarrhea has developed, most of the damage to
the intestine that leads to stunting has already occurred.
Sick kids are treated to save their lives and to limit
contamination of the pens, but the owner has already
lost control of this contagious disease. Several key
facts will help to design a prevention program. The
first is that the adult goats are the original source
of infection for young kids, because they shed oocysts
constantly. All old bedding and manure should be removed
from the kidding pens before the new kids are born.
Sporulated oocysts are commonly present on the skin
of the udder; thus the kid may become infected at
the same time as it takes its first drink of colostrum.
The doe's udder should be washed and dried before
the kid nurses or else the kid should be removed from
its dam at once and bottle or pan fed the colostrum.
10 If only one doe and her kid are
present on a farm, and the pens are dry and spacious,
coccidiosis is not apt to be a problem. The kids may
be safely left with the doe. In larger herds, it is
best to raise kids completely separate from the adults
until they are ready to breed. Even when rushed from
the doe to a clean barn, kids still manage to pick
up a few coccidia. As multiplication is rapid, a few
can become many very quickly unless good sanitation
is stressed. Fecal contamination of feed and water
must be prevented. This means that feeders and waterers
should be outside the pen whenever possible, and arranged
so that fecal pellets can't fall in. Grain should
be put in keyhole creep feeders rather than the open
troughs that kids love to play and sleep in. Hay racks
also must be covered to keep kids out.
11 Because oocysts have to sporulate
to become infective, exposure can be reduced by cleaning
the pens daily. Slotted floors are helpful. However,
daily cleaning entails a vast amount of work and give
disappointing results, if used alone. Ordinary disinfectants
don't destroy oocysts. Even 5 225683497622587700000000000000000000000000000000000
to concentrate on keeping the pens very dry, as mositure
is necessary for sporulation. Leaking waterers should
be fixed at once. Otherwise, the wet ground or floor
around the water source is a perfect environment for
oocyst sporulation. Small grassy ''exercise lots''
are also very dangerous and should not be used. It
is very important to avoid overcrowding; spreading
the kids out decreases the number of oocysts on any
given square inch of pen floor or pasture. If many
kids are present on the same farm, they should be
grouped by age. Putting a 2-week-old innocent kid
into a pen with kids 2 months old, where coccidial
numbers and immunity have been building up for some
time, is to invite disaster for the newcomer. Oocysts
are killed by very cold temperatures (far below zero)
or by hot dry conditions above 104. Thus, at the end
of the kidding season, pens and feeders should be
moved out into the hot sunshine for natural sterilization.
12 A variety of drugs may be given
orally to treat the kid sick with coccidiosis. These
include sulfa drugs such as sulfaguanidine and sulfamethazine,
tetracyclines (aureomycin or terramycin), and amprolium
(Corid R). Each of these has associated dangers if
overdosed. Sulfas can cause kidney damage in the kid
that is dehydrated. Tetracyclines will interfere with
rumen function in older kids and adults. Very high
levels of amprolium may lead to a fatal nervous disease,
called polioencephalomalacia, because of a thiamin
deficiency. Usually treatment is continued for about
5 days. Labels and veterinary instructions should
be followed. If the diagnosis is not certain, and
the kid may have bacterial enteritis or pneumonia
rather than coccidiosis, sulfamethazine or tetracycline
is usually given instead of amprolium.
13 All of these drugs are coccidiostats,
which means that they slow down rather than kill the
coccidia. Thus, if a kid is very heavily infected
when treatment is begun, medication may not help that
kid much. The drugs will greatly reduce the contamination
of the environment, and thereby give other kids time
to develop immunity. After kids have become immune
to the disease they still continue to shed oocysts.
Fecal exams may reveal thousands of coccidia per gram
of feces. Medicating these older kids or adults will
temporarily reduce the passage of oocysts but will
not improve growth rate. Within 2 or 3 weeks after
medication is stopped, coccidial levels will return
to pretreatment values. Thus, except for protection
of younger kids, it is a waste of time and money to
treat older apparently healthy animals that don't
show diarrhea. It is far better to separate the young
kids from these older carriers.
14 Medication of apparently healthy
animals is necesary for kids on large farms with previous
problems with coccidiosis. The aim is to prevent damage
to the intestines rather than waiting for diarrhea
to occur. For instance, it may help to treat the kids
with anticoccidial drugs on a daily basis for a week
or more before stressing them by weaning or moving
onto pasture. In some herds, a drug such as amprolium
may have to be given daily beginning at 2 weeks of
age and continuing until the kids are several months
old. Amprolium levels of 25-50 mg/kg daily should
be used. This is approximately 10-20 mg per round,
and is 21/2-5 times the treatment level recommended
for calves. Amprolium is not approved for use in goats
in this country. It can be given to each kid individually
or it can be mixed with the food or water. As an example,
if there are 50 pounds of small kids in a pen, 500
mg of amprolium is mixed with the water, milk or feed
that they will consume in one day. The larger kids,
by eating more, get more of the drug than do the smaller
kids.
15 Other newer coccidiostats may
be mixed with the feed, but most of them have not
yet been adequately tested on goats. Rumensin R (Monensin)
at 15 ppm in the starter grain has eliminated the
coccidiosis problem on at least one large goat farm.
This drug is very toxic to horses, so the medicated
feed should not be left where a horse can eat it.
Another potentially useful coccidiostat, now available
only for poultry, is lasalocid. This drug has protected
experimental lambs at 2-4 mg/kg/day. The poultry industry
has found that the coccidia often become resistant
to a drug after 1 or 2 years. Goat owners may also
need to change drugs if the one in use ceases to be
effective in controlling coccidiosis.
16 In summary, although most goats
carry coccidia and will have positive fecal exams,
normally only the young kids become sick with coccidiosis.
Deaths and stunted kids result. Raising kids separately
from adults, keeping pens clean and dry, preventing
fecal contamination of water or feed, and, in some
herds, continuous preventative medication are necessary
to prevent the disease. It is neither possible nor
desirable to completely eradicate coccidia from the
adult goats. A low level infection with the parasite
serves to keep these goats immune to the disease.
COCCIDIOSIS
COLLECTION;GOAT HANDBOOK
ORIGIN;United States
DATE_INCLUDED;June 1992
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