Volunteer Chassidy Klein demonstrates proper cleaning techniques as explained by Dr. Sockett during the Nov. 14 Calf Care Connection workshop held in Eau Claire, Wis. 
Volunteer Chassidy Klein demonstrates proper cleaning techniques as explained by Dr. Sockett during the Nov. 14 Calf Care Connection workshop held in Eau Claire, Wis. PHOTO SUBMITTED
    EAU CLAIRE, Wis. – According to Dr. Donald Sockett, DVM, from the Wisconsin Veterinary Diagnostic Laboratory, salmonella is an emerging problem in the dairy industry.
     He presented information about the strains of the bacteria and how to combat them on Nov. 14 during a Calf Care Connection workshop hosted by the Professional Dairy Producers of Wisconsin in Eau Claire, Wis.
    “The dairy industry provides a perfect environment for salmonella,” Sockett said. “It’s a ticking time-bomb for the industry.”
    Sockett pointed to non-sanitary designs of many facilities, which is a problem, particularly at the critical control points such as close-up pens, calving pens, hospital pens, the neonatal calf feed mixing rooms and the calf rearing areas.
    Vaccines are available to help prevent against salmonella infections, which Sockett calls an important tool that producers must use; however, he cautions that they can have limited results, ranging from only 25 percent to 60 percent efficacy. Vaccines do not actually provide protection against salmonella infection or prevent fecal shedding of the bacteria from occurring.
    According to Sockett, not all salmonella strains behave in the same manner, and in order to determine how to deal with them, the isolates must be serotyped to determine what strain of the bacteria is present.
    There are three tiers of salmonella. Tier 1 salmonella are non-invasive strains that cause no problems. Tier 2 salmonella are mildly to moderately invasive and are the most frequently occurring. They include strains such as Typhimurium and Montevideo. The dairy industry’s current best-practices are highly effective in combatting the stains that make up both Tiers 1 and 2. The most deadly strains are in Tier 3, which are highly invasive. The salmonella strains Panama, Dublin, Newport and Heidelberg are not effectively combatted with the industry’s current best-practices.
    One of the most concerning strains of salmonella to the dairy industry, particularly the dairy beef industry, is Heidelberg. The current outbreak of Heidelberg started in 2015 and peaked during the summers of 2016 and 2017. Eighty-three percent of the cases reported were in dairy beef calves that had a history of being trucked to a calf-raising facility.
    “Calves are put under the stress of going to the sale barn, they miss a meal or two, and then they are trucked to the farms,” Sockett said. “They start dying about five to 10 days after arriving, usually at about seven to 14 days of age.”
    The calves typically die within four to eight hours of the first signs of being ill, and death losses range from 20 percent to 65 percent of a calf group.
    Heidelberg is resistant to most drugs, making it difficult to treat.
    Salmonella is a zoonotic disease, meaning it can be transmitted to humans, and during this outbreak of Heidelberg there have been 56 human cases confirmed throughout 15 states. Of those, 17 required hospitalization and 66 percent were confirmed to have had direct contact with dairy beef calves that were sick with Heidelberg.
    According to Sockett, the best treatment is preventative, and he encourages all producers to be conscientious in the details of cleaning and sanitizing their facilities through several easy steps.
     “You can’t disinfect filth,” Sockett said. “It’s actually more important to clean than to disinfect. By cleaning you remove over 90 percent of the pathogens before you even start disinfecting. I’ll ask people about how they clean their facilities between calves, and they’ll tell me they removed the old bedding and spread barn lime. That’s not cleaning. Cleaning to a microbiologist is what happens after you remove the bedding.”
    Breaking up the biofilm layer that covers surfaces is the primary goal of proper cleaning. In cleaning livestock pens and trailers, Sockett does not recommend using a pressure washer because of the possibility of cross-contamination. He recommends taking swabs from the area to be cleaned prior to beginning and using an ATP meter to check the bacteria load in the area. Swabs can be repeated during the cleaning and disinfecting process to ensure the desired results are being achieved with a decrease in the amount of bacteria present with each step.
    After removing the bedding material, the first step is to properly clean to break up the biofilm by soaking the affected area thoroughly with hot water. Sockett recommends following that up with an alkaline foam cleaning solution that has a pH that ranges from 11 to 13. After thoroughly soaking the area with the alkaline foam, the solution should be allowed to sit on the surface for at least five minutes before being rinsed off with cold water.
    Then an acid foam cleaner, with a pH of three to four, should be applied using the foam sprayer. That should be allowed to soak for five more minutes before being rinsed with cold water again. The final step, after the area is dry, is the application of chlorine dioxide with the foam sprayer.
    “Chlorine dioxide is the world’s best sanitizer and disinfectant,” Sockett said. “It works like ozone, but is 1,000 times more soluble in water.”
    Sockett cautions not to use chlorine dioxide with warm water, as it has a boiling point of 51.8 degrees Fahrenheit.
    Chlorine dioxide eliminates both planktonic and sessile bacteria, migrating into the biofilm, destroying the habitat for bacteria. It provides a quick kill against coccidian and cryptosporidium oocysts; giardia cysts; bacterial, yeast and mold spores; salmonella; E. coli; rotavirus and coronavirus.
    In addition to these steps, Sockett encourages frequent replacement of boots, replaced at the first sign of wear. He also advocates wearing shoe covers over boots when entering calf areas.