Calf Scours – Causes And Management
LITTLE ROCK, ARK.
Calf scours or diarrhea is a very costly problem for many producers.
Calves that suffer from scours can become critically ill in a short
period of time. The possible pathogens that are the causative agents of
this disease are numerous. These infections lead to clinical signs such
as diarrhea and dehydration, but the critical issues occurring on the
calf’s body, electrolyte depletion and acid-base imbalances, can be the
underlying cause of the animal’s demise. If the calf fails to receive
the proper amount of colostrum, it will be more susceptible to the
pathogens that cause neonatal diarrhea.
The type of agents that lead to an infection can often be related to
the calf’s age as well as the integrity of the calf’s immune system. One
of the most important bacterial causes of scours is Escherichia coli
(E. coli). It typically affects very young calves less than a week old.
By releasing a toxin in the intestine, E. coli leads to what is termed
hypersecretory diarrhea. Signs include severe watery diarrhea that is
generally yellow to white in color. Calves are normally nonfebrile and
exhibit no blood, fibrin or mucus in their stool. Failure to promptly
treat this disease may lead to certain secondary problems such as
meningitis or polyarthritis.
There are primarily two viruses that can lead to diarrhea in young
calves. One is a rotavirus. This virus is very prevalent across the
U.S., and estimates are that 80 to 90 percent of adult cattle are
seropositive for this virus. The rotavirus survives well in the
environment, affects the small intestines leads to a malabsorptive
diarrhea. Most calves infected are from five to fourteen days of age. It
leads to a milder disease that has a lower mortality rate. Affected
calves may only show clinical signs of diarrhea for a few days. Another
virus leading to neonatal diarrhea is a coronavirus. This virus also
infects the small intestine and sometimes the proximal colon. It causes a
more severe, prolonged disease than rotavirus. Most cases are seen in
calves one to three weeks of age. Clinical signs include diarrhea and
occasionally mucus or bloody discharge and increased straining if the
colon becomes involved. Coronavirus leads to more intestinal damage and a
longer recovery period that rotavirus.
A protozoan cause of neonatal scours is Cryptosporidium. It mainly
affects calves one to three weeks of age and leads to a mild
malabsorptive diarrhea. The calves usually exhibit good appetites but
may show weight loss and emaciation if diarrhea continues for days to
weeks. This disease has a low mortality rate and is primarily due to
poor sanitation practices in the calf’s environment or with calf
equipment. Cryptosporidia can be zoonotic, meaning that people could
also be infected; therefore, people who treat infected calves should be
diligent about sanitation practices.
Coccidiosis is also a protozoal disease affecting calves three weeks
of age and older. It usually involves young, stressed animals. Stress
may be related to overcrowding, sudden changes in feed or poor
sanitation.
These infections are usually self-limiting, and mortality rates are
low. Symptoms include mild to severe bloody diarrhea, decreased
appetite, lethargy and dehydration. Clinical diagnosis is made by
finding significant numbers of parasites in a stool sample. Hygiene, dry
conditions and isolation of infected animals are indicated for further
prevention of coccidiosis.
Prevention is a key factor when dealing with calf scour issues on a
farm. In order to decrease the incidence of disease in the herd, it is
important to:
• Maximize colostrum transfer.
• Capitalize on environmental sanitation – clean boots; sanitize
bottles, buckets and feeders; minimize traffic from adult to calf pens.
• Minimize stressors such as overcrowding or poor nutrition.
• Vaccinate dry cows for E. coli, rota, corona and C. perfringens 60 days before calving
Recommendations for diseased calves should focus on these key factors:
• Correcting dehydration is critical, and correcting the fluid
deficit is the most important treatment for scours. The practice of
skipping milk feedings and replacing them with water can be very
detrimental. It is better to give regular feedings and add
water/electrolyte supplementation in between to correct dehydration. If a
calf is down and won’t suckle, IV fluids are typically needed.
• Treat electrolyte imbalances by adding electrolyte powders to oral fluids.
• Provide nutritional support since young animals have little energy reserve.
• Administer a systemic broad spectrum antibiotic if a bacterial
cause of scours is suspected, which can be beneficial to prevent
septicemia.
In the case of coccidiosis, a sulfa-antibiotic (sulfaquinoxaline,
sulfamethazine) or amprolium (Corrid) should be used because they are
effective against these infections. It is important to consult with your
local veterinarian, since he/she will know what diseases may be
prevalent in your particular area.∆