Beef/Cattle Extension Program
Calf Scours: Causes, Prevention and Treatment
by Don Hudson, D.V.M., R. Gene
White, D.V.M, University of Nebraska
* Editorial Note: This article was presented in
the Beef Questions and Answers newsletter, Montana Beef
"Calf scours is not
a disease--it is a clinical sign of a disease
which can have many causes."
Calf scours or calf diarrhea causes more financial
loss to cow-calf producers than any other disease- related
problem they encounter.
Calf scours is not a disease--it is a clinical sign
of a disease which can have many causes. In diarrheas,
the intestine fails to absorb fluids and/or secretion
into the intestine is increased.
A calf is approximately 70 percent water at birth.
Loss of body fluids through diarrhea can produce rapid
dehydration. Dehydration and the loss of certain body
salts (electrolytes) produce a change in body chemistry
and severe depression in the calf. Although infectious
agents may be the cause of primary damage to the intestine,
death from scours is usually due to loss of electrolytes,
changes in body chemistry, dehydration, and change in
acid-base balance rather than by invasion of an infectious
agent. The infectious agent that causes scours is important,
however, from the standpoint of prevention.
The age of the calf when scours begins is an important
consideration in its survival. The younger the calf,
the greater the chance of death.
Recent research has indicated that many scour cases
can be directly related to colostrum intake by the newborn
calf. A calf that is well mothered and consumes 1 to
2 quarts of colostrum in the first few hours after birth
absorbs a higher level of antibodies. This calf is far
less susceptible to scours and other calf hood diseases.
A reo-like virus can cause scours in calves within 24
hours of birth. However, when the infection- is first
introduced into the herd, it can affect calves up to
30 days of age or older. Infected calves are severely
depressed. There may be a drooling of saliva and profuse
watery diarrhea. The feces will vary in color from yellow
to green. Calves lose their appetite and the death rate
may be as high as 50 percent, depending on the secondary
Diagnosis depends on an accurate history, clinical
signs, and proper specimen collection and submission
to a laboratory. The reo-like virus infection alone
causes no diagnostic gross lesions in the intestine,
but there is an increased volume of fluid in both the
small and large intestine.
Scours caused by coronavirus occurs in calves that are
over 5 days of age. When the infection first starts
in a herd, calves up to 6 weeks of age may scour. These
calves are not as depressed as those infected Calf Scours:
Causes, Prevention and Treatment Don Hudson, D.V.M..,
R. Gene White, D.V.M, University of Nebraska with rotavirus.
Initially, the fecal material may have the same appearance
as that caused by rotavirus. As the calf continues to
scour for several hours, however, the fecal material
may contain clear mucus that resembles the white of
an egg. Diarrhea may continue for several days. Mortality
from coronavirus scours ranges from 1 to 25 percent.
Gross lesions are not significant. The intestine is
often full of liquid feces. If lesions are observed
in the intestine, they are the result of secondary bacterial
Treatment for coronavirus scours is the same as that
for rotavirus scours. Many herds have been found to
be infected with both the rota- and corona viruses.
A vaccine that is specific for the rota- and coronaviruses
is available. It can be administered in one of two ways:
orally to the calf soon after birth; or as a vaccination
to the pregnant cow. The first year that a vaccination
program is started in the beef cow herd, the cow receives
two vaccinations--the first at 6 to 12 weeks before
calving, and the second as close to calving as possible.
The next year, the cows are given a booster vaccination
just before calving. In herds where the calving period
extends over more than 6 to 8 weeks, cows that have
not calved at the end of a 6-week period should receive
a second booster vaccination. Following this procedure
insures that the calf receives a high level of rota-
and coronavirus antibodies in the colostrum. However,
the calf must receive adequate colostrum, preferably
within the first 4 hours after birth as the antibodies
cannot be absorbed later than 24 hours after birth.
This cow vaccination program fits well into a beef cow
herd health program and helps prevent virus build-up
in the herd.
Diagnosis of Rota- and Coronavirus Scours.
Accurate diagnosis of viral scours can be made only
by laboratory tests. Your veterinarian knows what material
to submit for examination.
Bovine Virus Diarrhea.
The virus of bovine virus diarrhea can cause diarrhea
and death in young calves. Diarrhea begins 2 to 3 days
after exposure and may persist for quite a long time.
Ulcers on the tongue, lips, and in the mouth are the
usual lesions that can be found in the live calf. These
lesions are similar to those found in yearlings and
adult animals affected with bovine virus diarrhea.
Diagnosis is by history, lesions, and diagnostic laboratory
assistance. Treatment is similar to that used for other
viral scours. Bovine virus diarrhea is controlled by
vaccinating all replacement heifers 1 to 2 months before
breeding. Caution: do not vaccinate pregnant heifers
or cows with modified live virus. Consult your
veterinarian before starting a bovine virus diarrhea
Escherichia coli (Colibacillosis). Escherichia
coli (E. coli) has been incriminated as a major cause
of scours. Many times this is the only organism identified
following routine bacteriologic culturing. Certain E.
coli can cause diarrhea. Many different serotypes (kinds)
of E. coli have been identified; some cause scours while
others do not. E. coli is always present in the intestinal
tract and is usually the agent that causes a secondary
infection following viral agents or other intestinal
E. coli scours is characterized by diarrhea and progressive
dehydration. Death may occur in a few hours before diarrhea
develops. The color and consistency of the feces are
of little value in making a diagnosis of any type of
diarrhea. The course varies from 2 to 4 days, and severity
depends on age of the calf when scours starts and on
the particular serotype of E. coli.
Upon postmortem examination, lesions are nonspecific.
However, the small intestine may be filled with fluid
and the large intestine may contain yellowish feces.
Diagnosis depends on an accurate history, clinical
signs, and culture of internal organs for bacteria and
serotyping of the organism. The location at which the
culture from the intestine was taken is also important.
Control of E. coli scours can be difficult in a severe
herd outbreak. All calves should receive colostrum as
soon after birth as possible. This helps the calf resist
E. coli infection. Early isolation and treatment of
scours helps to prevent new cases. There are new E.
coli cow vaccines now on the market. These vaccines
contain the K99 antigen which should give immunity to
many types of E. coli. The vaccine is administered 6
weeks and 3 weeks prior to calving. The new E. coli
vaccine is also available in combination with the rota-
and coronavirus vaccine. This vaccination builds high
antibody levels in the colostrum, but the calf must
get colostrum in the first few hours of life for the
vaccine to be effective.
There are more than 1000 types of salmonella, all of
which are potential disease producers. Salmonella produces
a potent endotoxin (poison) within its own cells. Animals
may be more severely depressed following treatment with
antibiotics as treatment causes the salmonella organisms
to release the endotoxin, producing shock. Therefore,
treatment should be designed to combat endotoxic shock.
Calves are usually affected at 6 days of age or older.
This age corresponds very closely to the age of the
coronavirus infection. The source of salmonella infection
in a herd can be from other cattle, birds, cats, rodents,
the water supply, or a human carrier.
Clinical signs associated with salmonella infection
include diarrhea, blood and fibrin in the feces, depression,
and elevated temperature. The disease is more severe
in young or debilitated calves. Finding a membrane-like
coating in the intestine on necropsy is strong presumptive
evidence that salmonella might be involved. Salmonella
isolations should be checked by a bacteriologic sensitivity
test to determine the antibiotics of choice.
Enterotoxemia can be highly fatal to young calves. It
is caused by toxins produced by Clostridium perfringens
organisms. There are 6 types of Clostridium perfringens
that can produce toxins, of which types B, C, and D
appear to be the most important in calves.
The disease has a sudden onset. Affected calves become
listless, display uneasiness, and strain or kick at
their abdomen. Bloody diarrhea may or may not occur.
It is usually associated with a change in weather, a
change in feed of the cows, or management practices
that cause the calf to not nurse for a longer period
of time than usual. The hungry calf may over-consume
milk which establishes a media in the gut that is conducive
to the growth and production of toxins by the clostridial
organisms. In many cases, calves may die without clinical
signs being observed.
Postmortem lesions may be a hemorrhagic intestinal
tract; thus, the common name, “purple gut.”
In the small intestine, there may be large hemorrhagic
or bloody, purplish areas where the tissue looks dead.
This is usually attributed to type C. Types B and D
may produce diarrhea without the usual postmortem lesions.
Diagnosis of these toxins is by finding the toxin in
the small intestine by laboratory methods. This toxin
breaks down rather rapidly so the contents of the intestinal
tract must be collected very soon after death and preserved
by freezing. Finding lesions of hemorrhagic enteritis
at postmortem in a calf that has died suddenly is basis
for a tentative diagnosis.
This disease is best controlled by vaccinating the
cows with Clostridium perfringens toxoid 60
and 30 days before calving. A single booster dose of
toxoid should be given annually thereafter before calving.
If this problem is diagnosed in calves from nonimmunized
cows, antitoxin can be given to the calf. Administration
of antitoxin and oral antibiotics is the only treatment
that is effective.
Other Causes of Scours
Coccidiosis is caused by one-celled parasites that invade
the intestinal tract of animals. There are many species
of coccidia. Two, Eimeria zurnii and Eimeria bovis,
are usually associated with clinical infections in cattle.
Coccidiosis has been observed in calves 3 weeks of age
and older, usually following stress, poor sanitation,
overcrowding or sudden changes of feed. It often occurs
in calves 7 to 14 days after they are moved from the
calving lots onto pasture.
Clinical coccidiosis is diagnosed by finding significant
numbers of parasites in the feces. The results of the
fecal examination must be related to the clinical signs
and intestinal lesions. Occasionally, clinical coccidiosis
will be present with bleeding and very few parasites
in the fecal material.
Laboratory examination of sections of the intestine
may be required for diagnosis. A typical sign of coccidiosis
in young calves is diarrhea with fecal material smeared
over the rump as far around as the tail will reach.
This may or may not contain blood. Death may occur during
the acute period or later from secondary complications.
Sulfonamides have been the treatment of choice for
coccidiosis for many years. If treatment is given before
signs appear, the disease can largely be prevented.
Amprolium has been cleared for use in calves as a preventative.
This should be supplied at the rate of 5 mg/kg of body
weight for a period of 21 days to cover the time period
during which this disease is anticipated. Good feeding
practices, management, and sanitation are the control
methods of choice.
Cryptosporidium is a protozoan parasite that is much
smaller than coccidia. It has the ability to adhere
to the cells that line the small intestine and to damage
the microvilli. Several reports from researchers and
diagnosticians have associated cryptosporidium with
outbreaks of calf scours. As a rule, cryptosporidium
is detected in combination with coronavirus, rotavirus,
and/or E. coli. Calves infected by cryptosporidium have
ranged from 1 to 3 weeks in age.
Under range conditions, a calf adapts a pattern of
nursing that fills his needs. Nutritional scours can
be caused by anything that disrupts this normal habit.
A storm, strong wind, or the mother going off hunting
for new grass disrupts the normal nursing pattern. When
the hungry calf does get an opportunity to nurse, the
cow’s udder may contain more milk than normal
and the calf may overeat resulting in a nutritional
scours. Erratic nursing patterns may also be conducive
to enterotoxemia. Nutritional scours is usually white
scours caused by undigested milk passing through the
This type of scours usually presents little problem
in treatment. If the affected calves are still active
and alert, no treatment is required. If the calf becomes
depressed or fails to nurse, it should be treated. Oral
antibiotics can be used as a treatment.
Treatment of Calf Scours
Treatment for scours is very similar regardless of
the cause. It should be directed toward correcting the
dehydration, acidosis, and electrolyte loss. Antibiotic
treatment can be given simultaneously with the treatment
for dehydration. Dehydration can be overcome with simple
fluids given by mouth early in the course of the disease.
If dehydration is allowed to continue, intravenous fluid
treatment becomes necessary. The clinical signs of dehydration
first occur when the fluid loss reaches 5 to 6 percent
of the body weight. Ten percent loss of fluid results
in depression, sunken eyes, dry skin, and the calf will
probably be unable to stand. A 15 percent loss of fluids
usually results in death. Oral fluids used early in
the scouring process have been quite successful. Consult
your veterinarian for electrolytes to be given orally.
There are dry electrolyte powders available that can
be mixed with water for oral administration.
If electrolyte powders are not available, there are
three solutions for oral administration that can be
prepared on the ranch:
- Combine 1 can beef consomme, 1 package fruit pectin
(Sure Jell or Pen Jel),2 teaspoons low sodium salt
(Morton Lite Salt), 2 teaspoons baking soda, and add
enough warm water to total 2 quarts.
- Combine 1 can beef consomme, 3 cans warm water,
and 1 heaping tablespoon baking soda.
- Combine 1 tablespoon baking soda, 1 teaspoon salt,
and 250 cc (8 ounces) 50% dextrose or 8 ounces light
Karo syrup, and add enough warm water to total 1 gallon.
Do not overfeed! Administer up to 1 quart of any of
these three solutions every 3 to 4 hours, depending
upon the degree of dehydration and fluid loss. These
solutions can be used as the only source of nutrients
for a period of 24 to 48 hours. Do not use milk or milk
replacers during this period, as milk in the intestinal
tract makes an ideal medium for bacteria such as E.
coli to grow. Return the calf to the cow, which has
been previously milked out, as soon as the calf is able
to follow its mother.
Giving electrolytes orally is always a problem unless
the calf will nurse from a bottle. There is an esophageal
probe available which works very well for administering
oral fluids to calves. This device, or a stomach tube,
should be used when giving calves large amounts of fluids.
If using a stomach tube, do not go into the stomach
with the tube as this puts the material in the nondeveloped
rumen rather than into the true stomach where it should
be administered. To avoid the rumen, insert only 18
inches of the stomach tube into the calf’s mouth.
Antibiotics should be used both orally and by injection
whenever treating calves for diarrhea. In acute salmonellosis
outbreaks, antibiotics may cause the release of excess
endotoxins; therefore, consideration should be given
to using fluid therapy only.
Ear tag treated calves for identification and keep
a daily record on the treatment administered. This aids
in evaluating the treatment and utilizing follow-up
treatments as necessary. Valuable information can be
obtained by having the cows identified and identifying
each calf at birth. If an outbreak of scours occurs,
persistent treatment and records are essential for doing
a good job.
Scour problems are an ever-existing threat to baby
calves. A good program of adequate nutrition, sanitation,
management and a good herd health program are necessary
to minimize the incidence and losses. Early diagnosis
and treatment will reduce the threat of a herd outbreak.
The correct diagnosis is also very important when considering
vaccinations and other procedures for the cow herd the
next calving season. Calf Scours, from p. 9
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