BUILDING THE CALF MICROBIOME: THE BATTLE BETWEEN BENEFICIAL BACTERIA AND EVIL PATHOGENS

Written by: Steve McGill

A well-balanced microbiome is beneficial for immune function, gut microbiota, the function of the gut barrier, and the key evolutions of core microbiota in the gut of calves of all ages. The cell structure of a gut micro-bio is beneficial and essential for nutritional, immune system development, and the long-term health of the calf as it matures into a productive animal. Poor microbiome leads to digestive diseases in calves, like diarrhea and intestinal inflammation. The microbiome within a cow’s gastrointestinal tract comprises a diverse population of bacterial species that play a crucial role in health, immune response, and productivity. The development of a mature cow’s microbiome is a dynamic process that begins at birth and evolves throughout the cow’s life. At birth, a calf’s gastrointestinal tract is essentially a clean slate, with its initial bacterial population derived from the mother. The calf’s immune system is naive, and its microbiome is virtually nonexistent, making the early days critical for establishing a healthy microbial community. This period represents a pivotal competition between beneficial bacteria and potential pathogens. To ensure the development of a healthy microbiome, it is imperative to initiate the transfer of immune knowledge from the cow to the calf through colostrum immediately after birth. The significance of this process in fostering a robust microbiome in the calf cannot be overstated.

To ensure an effective colostrum delivery process, follow these steps:

Vaccinate the cow: Quality colostrum begins with colostrogenesis, where immunoglobulins are transferred from the cow’s blood circulation to the calf via the mammary gland. Cows with higher levels of immunoglobulins produce superior colostrum. Vaccination enhances antibody levels for specific diseases in the cow, which are then transferred to the calf through colostrum.
Proper harvesting: Capture colostrum from mature cows in a clean environment. Test it for quality — high-quality colostrum should have an immunoglobulin level exceeding 50 mg/ml, be free of blood, and have a standard plate count of less than 50,000 colony-forming units per ml. Pasteurize the colostrum before storing or feeding it to the calf.
Feeding promptly: Calves should be fed approximately 10% of their body weight in colostrum, about four quarts. Since the calf’s abomasum cannot handle this volume at once, divide it into two feedings. The first feeding should occur within 1–2 hours of birth and the second within 12 hours. Time is critical, as the intestinal gaps that absorb colostrum close within 24 hours.
Feed a highly nutritious diet: Start your calf’s diet on day two or three with a high plain of nutrition with one pound of solids. Increase these solids until you have the calf on two-plus pounds of solids daily by week three or four. Make sure your protein-to-fat ratios are correct to maintain proper growth. The right stature for body weight is important. Generally, consult your calf specialist for a recommended replacer to complement your on-farm feedstuffs.

While establishing an immune system in the calf to combat pathogens, creating a clean, pathogen-free environment for the calf’s birth and initial hours of life is essential. Although a completely antiseptic environment is impractical, measures can be taken to minimize pathogen presence in the calving area. To ensure a professional and effective approach to colostrum delivery and calf rearing, consider the following steps:

Use clean, dry bedding: Utilize straw or wood shavings as bedding. Ensure that soiled or wet bedding is promptly removed and replaced with clean, dry bedding after each calving
Regularly disinfect the calving area: Depending on your facilities and the number of calves born daily, it may not be practical to disinfect the entire area between each calving. If possible, create individual calving areas that can be cleaned and disinfected without disrupting the rest of the herd. Use a broad-spectrum disinfectant effective against viruses (e.g., rotavirus, coronavirus), bacteria (e.g., E. coli, salmonella), and parasites (e.g., cryptosporidium)
Enforce employee cleanliness: Ensure that all personnel entering the calving environment maintain high standards of cleanliness. Minimize the transfer of bacteria and pathogens from the milking herd to the calving area using dedicated coveralls and boots. Employees should have clean hands and use disposable gloves when handling calves. Consider implementing footbaths before entering the calving facilities.
Clean equipment: Disinfect all equipment used in the calving process, especially those involved in the collection, storage, and feeding of colostrum, between uses

Once you get through the critical first 24 hours, the job of building the microbiome does not stop there. Pathogenic bacteria can enter the calf through soil, water, and feed. Provided that calf milk replacer is mixed with clean water in a clean mixing tank with clean utensils it should be sterile. Consider using a probiotic with your calf milk replacer to help fight the pathogen burden that your calves are facing. Given your daily presence on the dairy, it may be challenging to identify areas for improvement in your calf management system. Therefore, it is advisable to seek external assistance to evaluate your program. Engage a DFA Animal Nutrition calf specialist to analyze all aspects of your calving program, from dry cow care to post-calving processes. They can identify potential entry points for pathogens and recommend control measures. Additionally, they can provide training and resources for your team on proper calving protocols. Establishing a healthy gut microbiome from day one of a calf’s life is crucial. The competition between beneficial and harmful bacteria is significant, and the outcome will influence the calf’s health and productivity throughout its life. Investing in a healthy microbiome will yield substantial benefits, including higher productivity once the calf joins the milking herd. Contact your local calf care specialist for advice on how to build your calves’ microbiomes.