Bloody Scours - What do they mean?

Discovering blood in calf scours can be alarming. However, when the cause is identified, it is possible to successfully treat the calf and prevent the spread of the disease. Although sometimes newborn calves will have a little blood or mucous in their stool, most of the time bloody scours indicates intestinal damage. 

There are typically 3 main causes of bloody scours; salmonella, coronavirus, or coccidiosis. Each one of them are completely different pathogens and require different approaches to treat.

Salmonella is an infection of the intestinal tract caused by a bacterium called Salmonella enterica. Common strains effecting calves are Salmonella Newport, Salmonella Dublin, Salmonella Typhimurium, and Salmonella Heidelberg.

Infection can be passed by seemingly “healthy” animals or by those showing acute symptoms. Calves that are colostrum deprived or have failure of passive transfer are most at risk of becoming infected. Disease onset will typically occur around 5-14 days of age.

Salmonella causes a malabsorptive diarrhea as it destroys a lot of the intestinal cells and the microvilli. Infected calves may have a fever of (105-107 degrees F/ 40.5-41.6 C), diarrhea containing blood and mucus, and will rapidly dehydrate. 

Treatment should include supportive therapy to keep the calf hydrated and to correct blood acidosis. Antibiotics may be given as this is a bacterial disease.  Work with a veterinarian who has knowledge of the drug resistance patterns of organisms previously found in your area. They will be able to help you select an antibiotic that will be most effective.

As antibiotic resistance increases, it is becoming more important to find alternative solutions. In a study performed by Dr. Alfanso Lago, DVM, Surveillance Calf was found to bind more than 40% of Salmonella Newport, Dublin, and Typhimurium when fed at the maintenance level of 6 ml/day. When given to calves at a higher level of 20 ml/day, Surveillance Calf bound 100% of all 3 strains of Salmonella. Visit with your veterinarian about alternative solutions such as Surveillance that may be beneficial for use on your operation.

Coronavirus attacks the cells of the small intestine, as well as some of the cells of the colon. It completely destroys the villi and causes a malabsorptive diarrhea.  Calves with coronavirus are often also infected with rotavirus, or secondary bacterial infections. 

Infected calves are usually 5-30 days of age and may also exhibit respiratory problems. The disease is passed through shedding in the feces of infected animals.

Treatment should include supportive therapy to correct hydration and restore acid-base electrolyte balance.

Coccidiosis is an infection by the coccidia parasite. This can occur anytime from about 3 weeks of age to several months of age. The coccidia parasite has a 3-week incubation period from the time of infection, to the shedding of infectious parasites into the environment.

Most coccidiosis infections are subclinical. Calves may appear unthrifty, have watery feces with or without blood. Severely infected cattle have thin bloody diarrhea that may last for more than one week. Animals will appear depressed, may develop a fever, and lose weight.

Coccidiosis is a self-limiting disease, and spontaneous recovery without specific treatment is common once the multiplication stage of the coccidia has passed.  Drugs that can be used to treat coccidiosis include; sulfa quinoxaline, amprolium, decoquinate, lasolocid, or rumensin.

All three of these “causes” of bloody diarrhea are completely different. It is extremely important to work with your veterinarian to accurately diagnosis the cause and prescribe an effective treatment. 

In all cases of calf scours. It is important to provide supportive therapy in the form of extra fluids and electrolytes to correct acid-base imbalances.  Surveillance Calf and Sync can also provide an effective scour solution as they bind pathogens, support the immune system, and improve gut health. 

You can shop for Surveillance Calf and Sync at the Calf Distinction Store. 

Written by: Mariah Gull, M.S.