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Probiotics play an essential role in early calfhood diarrhea prevention

Kimberley Morrill, David Ledgerwood and Keith A. Bryan for Progressive Dairy Published on 30 April 2021

Day in and day out, dairy farmers provide the best in animal husbandry. There are occasions when animals get sick and need antimicrobial therapy to overcome a specific disease challenge.

Prudent use of antimicrobials is of great importance for today’s modern dairy farms. The avoidance of milk and meat residues in the dairy industry takes an on-farm team effort.



A key component of judicious antimicrobial treatment is only treating animals when antimicrobials are expected to have added value. In simple terms: If the animal does not have a bacterial infection that would respond to antibiotics, don’t use them. The first step in reducing antibiotic usage is focusing on prevention, followed by reducing the risk of spreading the infection to herdmates. Treatment protocols and compliance become important to optimize cure rates and minimize recurrent episodes.

Let’s focus on reducing sick calves, specifically those with digestive challenges. Based on USDA data, 21% of pre-weaned calves are affected with digestive problems; 75.9% of these calves were treated with antimicrobials, and 54.6% of pre-weaned calf deaths were due to digestive problems. If we were to apply those numbers to a farm raising 500 calves per year, that would equate to 105 calves per year with a digestive problem and 80 calves that were treated with antibiotics.

Prevention is key

When we step back and look at what organisms cause calfhood scours, we realize very quickly that not all organisms are bacteria (Figure 1), and antibiotics are not always our best option.

Common organisms responsible for calfhood diseases during the first 80 days of life

This is where prevention becomes even more important – we shouldn’t be using an antibiotic to treat a virus (rotavirus and coronavirus) or a protozoa (cryptosporidium and coccidia), as it won’t have an impact on the organism causing the disease.


Many times calf diarrhea problems are caused by a combination of factors, not all of which are infectious. Inconsistent feeding practices such as continually changing the source of milk, the fat and energy content of milk, timing and volume of feeding can lead to digestive upsets and changes to the normal microbiome of the gastrointestinal (GI) tract. Pathogenic bacteria, as well as viruses, protozoa and parasites, can be transmitted to calves through nose-to-nose contact, fecal contamination of feed, as well as contaminated milk. Poor hygiene practices including dirty feeding equipment, dirty pens and even employees can also cause the introduction of pathogenic organisms. When calves are normal, healthy and not under stress, they are often able to fight off many pathogens; however, when the calf is under stress, and the immune system becomes compromised, these pathogens are able to flourish and cause illness.

Specific prevention of digestive illnesses begins in the calving area. Calves should be born in a clean area and moved into a clean pen that limits their exposure to pathogens from the environment (manure) as well as those carried by older animals. Colostral immunity is an essential part of enteric disease management, and all calves should receive high-quality colostrum (greater than 50 milligrams IgG per millilitre) within the first few hours of birth. While colostrum is one of the most important management practices, we need to look at other management practices that help keep calves healthy throughout the pre-weaning and weaning period.

The use of probiotics has increased in popularity as an alternative therapy that helps reduce the use of antibiotics through prevention of illness and, thus, reduces the emergence and spread of antibiotic-resistant bacteria and residual antibiotics in milk and meat. Lactic acid bacteria (LAB) are natural components of the normal intestinal microbiota in both humans and animals and have been used to control the effects of pathogens such as Salmonella spp. and Escherichia coli. In addition to LAB, bacillus organisms have emerged on the probiotic market with benefits including enzyme production that improve digestion of feed and aid in absorption but also the ability to attack potentially pathogenic bacteria through the production of bacteriocins.

Direct inhibition of Clostridium perfringens Type A, Clostridium perfringens Type C and Salmonella enterica typhimurium are observed with specific probiotic strains of Bacillus licheniformis in an in vitro model designed to look at pathogen inhibition. These four pathogens (salmonella, Clostridium perfringens Type A and Type C, and E. coli) were chosen since they are the most common bacterial pathogens associated with calfhood diarrhea during the first 30 days of life.

It’s important to reduce the prevalence of GI infections in young calves because when animals are sick at this stage, their subsequent growth is impaired, thus affecting their future productivity. Research from Cornell University estimates that pre-weaned calves treated with antibiotics produce around 500 kilograms less milk in their first lactation as compared to healthy calves. A separate study from Cornell University reported that the average treatment cost (medicine only) per calf was $18.17 (ranging from 20 cents to $129.11), with the average treatment cost (medicine only) for scours being $1.12 (ranging from 36 cents to $29.12; Table 1).

Average cost of treatment by illness and overall total treatemtn cost per calf


These two studies confirm that calfhood illness is expensive and has a long-lasting impact.

If we go back to our earlier example of 500 calves per year, with 80 calves being treated with antibiotics, we suddenly see our treatment cost (antibiotics only) for just digestive challenges being $89.60. While this might not seem like a lot, that just includes the cost of antibiotics. That value does not include the additional cost of electrolytes, labour, diagnostic testing, lost revenue due to poor growth, dead calves, later entry into the milking herd or lost revenue from lower milk production.

Treatment protocols

Treatment protocols should be written for common calfhood illnesses your calves experience on your farm and should be developed with your herd veterinarian. The protocol should include disease identification, treatment course, including what antibiotic should be given (if any), the dosage, where and how to administer the treatment, how often the injection should be given and the withdrawal time. The treatment protocol should also include who the employee should contact if there is a question. If only certain people are allowed to treat animals, all employees should know who they are and how to contact them. The last part of the protocol should be record-keeping. Without written treatment records, it’s unknown as to what animal was treated. This can lead to an animal accidently being sent to slaughter with a residue. Treatment records also play a valuable role in evaluating calf management practices and disease outbreaks, but that’s a topic for another article.

Calfhood illnesses, specifically digestive challenges, can lead to long-term revenue losses for dairy producers. Prevention during the first weeks of life by providing science-based, research-proven microbial support in milk (or milk replacer) provides an opportunity to complement current management practices and can help reduce the risk of diarrhea caused by pathogens. This allows nutrients to be used for growth and aids in the goals of reducing antibiotic use and managing treatment costs while supporting enhanced growth and productivity. The end goal is to have normal, healthy and productive animals.  end mark

David Ledgerwood is a technical service manager for silage inoculants and cattle probiotics with Chr. Hansen Animal Health & Nutrition. Keith A. Bryan is a technical services manager, Ruminant DFM & Silage Inoculants, with Chr. Hansen Animal Health & Nutrition.

References omitted but are available upon request. Click here to email an editor.

Kimberley Morrill
  • Kimberley Morrill

  • Technical Service Manager
  • Chr. Hansen Animal Health & Nutrition
  • Email Kimberley Morrill