Drs. Samantha Locke, Alex Fonseca-Martinez, and Greg Habing, Department of Veterinary Preventive Medicine, The Ohio State University
Cleaning and disinfection (C&D) practices are often laborious and time-consuming, but successful C&D is critical to reducing cattle exposure to pathogens, even if you don't see an immediate response. Many factors can influence the effectiveness of your cleaning and disinfection practices on any given day. Some things are difficult to control, for example, temperature and relative humidity can impact the success of your hygiene practices. However, there are strategies you can implement to make the most out of your C&D (Figure 1).
The Basics 
- Plan your C&D. Organize your C&D in a way that would minimize the impact of pathogen spread. For example, when possible, clean and disinfect starting with the youngest animals moving to the oldest. In lactating barns, scrape beds before flushing alleyways. After flushing, scrub water troughs.
- Don't forget the cleaning in cleaning and disinfection! Organic material, such as manure or feed residue, that are left on surfaces can interact with disinfectants and reduce their effectiveness. Rinsing or sweeping away any visible contamination from surfaces is the first step to successful C&D.
- Include a washing step. Washing equipment or surfaces with soap or detergent can remove residue that was left behind after rinsing/sweeping an area – some soaps can even eliminate certain microorganisms. Scrubbing can also help remove strongly adhered residues or biofilms that would interfere with disinfectants. Just make sure to rinse away any product used, as disinfectants can be inactivated by soap. Note: it can be tempting to use pressure washers to efficiently clean heavily soiled areas; however, these should be used with caution. Some pathogens, like Salmonella, can be spread further with pressure washing and can cause animal and human health concerns.
- Let areas/equipment dry before disinfection. Extra water can dilute disinfectants, reducing their working concentration and effectiveness. If allowing an area to dry completely is not possible, try to allow at least 5 to 10 minutes before applying a disinfectant.
- Have a plan for cold weather C&D. Cold temperatures can negatively impact disinfectants. If temperatures are predicted to rise throughout the day, consider moving your C&D to whenever the warmest temperatures will be reached. Alternatively, some disinfectant companies have instructions on how to add antifreeze to their products to preserve their effectiveness in winter conditions.
How Much C&D is Enough?
If you want your C&D to be successful, routine is important, but it can be difficult to identify how often different areas or equipment should be cleaned. Supplies like calf bottles, esophageal tubers, and calving chains should be cleaned after each use. Daily cleaning of animal housing areas is often not considered feasible from a time and labor standpoint. Intermittent cleaning (for example, weekly or monthly) allows bacteria to establish biofilms. Biofilms are communities of microorganisms that attach to a surface and produce a protective “slime". They are extremely resistant to disinfection and can persist in environments for a long time, consistently causing contamination issues with farm equipment. Biofilms can even result in animal infections. Porous surfaces and areas with lots of cracks, crevices, and hard to reach corners are difficult to clean, and provide lots of opportunities for biofilm formation. In laboratory settings, Salmonella can form biofilms within 48 hours. Currently, very few disinfectants have been tested to determine their effectiveness against biofilms. If C&D of animal housing can't be completed daily, consider adopting a more rigorous protocol in order to disrupt biofilm formation and make sure that your efforts are having an impact.
What is the Best Disinfectant?
Disinfectant choice is specific to your facility and which pathogens you are most concerned with. Discuss with your veterinarian what disinfectants and C&D protocols may work best for your herd. However, here are some tips to make sure the disinfectant you choose will give you the most bang for your buck.
- Check the label. Companies often list the organisms that a disinfectant has been tested against in the lab and found effective. Double check to make sure the microorganisms that cause the most problems in your herd are covered.
- Actively manage your disinfectants. Some products - like bleach - can lose strength over time. Test strips are available for most disinfectants to ensure that: 1) Concentration of your stock is known and 2) Disinfectants are mixed appropriately when diluted. Disinfectants applied at lower concentrations than instructed on the label are usually ineffective.
- Follow the contact times listed. The ability of disinfectants to inactivate or kill microorganisms is a function of concentration and contact time. Failing to follow label guidelines regarding concentration and contact times will negatively impact C&D.
Unfortunately, there is no perfect cleaning and disinfection protocol available. However, if you keep in mind the information provided above, you can avoid common mistakes that reduce the effectiveness of C&D protocols.
If you’re interested in learning more about cleaning and disinfection and how to develop your C&D program, check out https://www.cfsph.iastate.edu/infection-control/disinfection/.