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Calf scours: Key considerations for prevention, treatment and recovery

Zach Janssen for Progressive Dairy Published on 31 July 2020

Scours – it’s an unwelcome but far too common problem on many dairies today. Thanks to education and development of new products, tremendous strides have been made in reducing the severity and number of calves lost due to the main causes of calf scours.

These primary causes remain the same: bacteria (E. coli, Salmonella sp.), viruses (rota, corona) and parasites (cryptosporidia, coccidia). Work with your veterinarian to identify the timeline of when calves are affected and use diagnostic testing. This is a straightforward way to determine which pathogens are prevalent on your farm and develop a prevention and treatment plan to deal with calf scours.



Scours prevention

Scours prevention is the best strategy to help your calves stay healthy and realize the genetic potential we have been working so hard to achieve. Cleanliness is a cornerstone of prevention, and it starts in the calving pen by providing a clean area so the calf is not exposed to that first “manure meal.” It is also critical to keep colostrum harvesting, storage and administration equipment clean and free of biofilms.

Equally as critical is to get the sufficient amount (4 litres) of high-quality (50 grams per litre IgG, greater than 22 Brix) colostrum into calves as quickly as possible (less than six hours after birth). High-quality colostrum is produced by healthy dry cows and springing heifers on a vaccination program to cover pathogens endemic to your farm, kept on a proper plane of nutrition and comfortably housed. Oral antibodies and vaccines administered to the calf at birth can be an effective tool as well.

Scours treatment

Although scours prevention is the objective, even the best calf managers will have to deal with calf scours. This means an intervention or treatment. The three main goals of treatment therapy should be to:

  1. Combat the scours-inducing pathogen

  2. Meet the calf’s physiologic needs (hydration, energy, acid/base balance)

  3. Restore gut health

Early in my career, it was not uncommon for farmers to try and combat calf scours by feeding a milk replacer medicated with the mycin twins, “neo” and “terra.” Public perception on overuse of antibiotics and the implementation of the veterinary feed directive (VFD) have curbed this practice. Blindly reaching for an antibiotic to treat calf scours should be critically evaluated.

The vast majority of calf scours is caused by rotavirus and cryptosporidium, neither of which will respond to antibiotic therapy. Scours-causing pathogens such as Salmonella sp. may be resistant to the antibiotics we legally have available to treat calf scours. And indiscriminate use of antibiotics may harm the natural flora or beneficial bacteria of the calf’s gut.


Critically important in treating calf scours is the selection of an appropriate oral electrolyte solution (OES). This solution must meet the calf’s physiologic needs by providing the proper amount of sodium, amino acids including glycine to promote the absorption of sodium, energy sources such as glucose to correct hypoglycemia and a buffer to correct metabolic (blood) acidosis, with acetate and propionate being the preferred alkalinizing agents.

Pay close attention to the osmolarity of the OES, with 400 to 600 mOsm per liter being ideal. Continue to feed milk, as it will be the calf’s main source of energy. The old idea of starving the diarrhea-causing bugs will also starve the calf. Finally, resist the urge to mix the electrolyte into the milk or milk replacer to save labour. This practice can cause the osmolarity to increase and actually worsen diarrhea by drawing fluid into the intestines. Calves will also benefit from the hydration the additional water mixed with the electrolyte provides.

All-natural options for combating scours-causing pathogens have demonstrated efficacy. Yeast cell wall, aka mannanoligosaccharides (MOS), can bind to pathogens before they have the ability to attach and destroy the absorptive layer of the small intestine. In addition, these compounds act as prebiotics or nutritional sources for beneficial bacteria such as Lactobacillus. Oregano oil with the active ingredients of carvacrol and thymol can inhibit pathogens, including parasites, and have the added benefit of stimulating the calf’s appetite.

Feed probiotics

Finally, providing a probiotic product, also commonly referred to as direct-fed microbials (DFMs), can boost the calf’s immune system and restore gut health after a scouring episode. These products contain targeted beneficial bacteria to enhance the normal microbiota and may also contain immune-stimulating vitamins such as vitamin A and vitamin E. Calf raisers can add them to milk, milk replacer or feed for seven to 10 days after treatment for scours. It is also common to feed a probiotic product for the first 14 days of life, as it represents the highest risk in a calf’s life for contracting scours-causing organisms.

Work closely with your veterinarian and animal health provider to implement protocols for effective prevention and treatment strategies when you have to deal with calf scours.  end mark

Zach Janssen is a bovine technical services veterinarian with TechMix. Email Zach Janssen.