Updated: May 30, 2020
Diarrhea, commonly called scours, is one of the most common diseases affecting young livestock. It is important to identify the cause to successfully prevent and manage this disease. Inadequate nutrition (especially colostrum), a crowded or dirty environment, weather, and stress can all cause or exacerbate scours outbreaks, in addition to the many infectious causes of disease.
Ten Causes of Scours
These are the major causes of scours in rough order of the age that they affect livestock:
E. coli is primarily a disease of a dirty environment and can rapidly affect animals in the first few days of life. Sudden death is possible.
Rotavirus and Coronavirus only affect calves in the first few weeks of life. Lambs and kids are also susceptible to rotavirus, although this is a less common cause of scours for them.
Cryptosporidium is a protozoan parasite that is very hardy in the environment and can cause serious disease in humans!
Coccidiosis is a disease of stress or poor hygiene typically seen prior to six months of age. A coccidiostat, such as Bovatec, can aid in prevention. Bloody stool is possible and severe cases may exhibit neurologic symptoms.
Clostridium perfringens (enterotoxemia, overeating disease) can cause diarrhea and sudden death, primarily in small ruminants, but also in calves. Treatment is not always effective due to the rapid course of disease, but it is preventable through vaccination.
Yeasts and molds can be secondary invaders found in the guts of animals treated with multiple rounds of antibiotics.
Worms do not affect animals until they start grazing. While cattle tend to become fairly resistant to worms as they mature, small ruminants remain susceptible throughout life. Barberpole worm can become severe in sheep and goats without causing diarrhea so it is also important to watch your herd for signs of anemia or weight loss.
Salmonella can affect animals of any age and can infect humans. Blood, mucus, or fibrin in the diarrhea combined with a fever are signs indicating that salmonella is at play. Endotoxic shock, pneumonia, late-term abortion, and sudden death are possible. Aggressive treatment with antibiotics, anti-inflammatories, and fluids is necessary.
Bovine Viral Diarrhea can affect cattle at any age and is preventable through vaccination. Persistently infected individuals and reproductive disease is also possible.
Nutrition can also be an important cause of scours. Milk replacer that is poor in quality, mixed improperly, or overfed is a common cause of scours in bottle-raised babies. Lush pasture or a high concentrate diet can cause diarrhea. Young stock on lush pasture must consume a large amount of grass to meet their nutritional needs. Rumen acidosis caused by a sudden large intake of grain can cause diarrhea in ruminants of any age. Bloat, depression, laminitis, and even death are possible. If a known exposure occurs, it must be treated aggressively.
Six Ways to Fight Scours
Most scours can be prevented with attention to environment, nutrition and minimizing stress. Vaccination works for some of the diseases, but is less effective for others.
Treatment should focus on fluid therapy. Dehydration is the most common cause of death in scouring animals. Milk must be fed to meet nutritional needs of the animals. Depending on the degree of dehydration, oral electrolytes and subcutaneous or intravenous fluids may also be needed. These are other treatments to consider on a case-by-case basis:
Temperature: It’s important to ensure scouring animals are maintaining a normal temperature. It is possible for them to lose significant body heat. Always warm animals to a normal temperature before feeding milk.
Correct any nutritional issues.
Pepto bismol and anti-inflammatories can help in some cases. Use caution with anti-inflammatories in dehydrated individuals.
Yogurt or probiotics can help repopulate the gut flora.
Antibiotics are usually not necessary. Scours is most commonly caused by viruses, coccidia or nutritional issues, none of which respond to antibiotics. However, any of these causes of diarrhea can lead to secondary bacterial infection if there is severe gut damage. These animals will typically appear depressed and have a fever. Antibiotics are necessary in these cases, as well any time that E. coli or Salmonella are suspected.
Beef calves with runny stool who are bright and alert, staying with the herd, and nursing well, may not require any treatment. Their appetites and attitudes should be monitored closely so that timely intervention is possible with any change.
Consultation with your veterinarian is recommended to develop the best prevention and treatment strategies for your herd.