Calf Scours – Causes And Management

DR. JEREMY POWELL

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.∆
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