Properly selecting, using disinfectants is critical to maintain herd health
Today’s confinement livestock operations help keep animals safe from diseases transmitted by wildlife and other outside sources. Yet, understanding the basics of cleaning and disinfecting barns is an important step for biosecurity protocols.
“Because we have the advantage of keeping animals confined, we minimize the risk of new introductions to diseases we don’t already have on our farm,” says Alejandro Ramirez DVM, MPH, PhD, Diplomate ACVPM, associate professor, Veterinary Diagnostic and Production Animal Medicine at Iowa State University. “The second part of our biosecurity is, once we have something in our farms, how do we control it to make sure it doesn’t spread to other farms and other stages of production.”
For example, porcine epidemic diarrhea virus (PEDV) may cause only minor health consequences infinishing operations. Yet, it can have devastating effects if carried into farrowing operations, Ramirez says. The goal of biosecurity is to minimize the risk of infection between different farms, stages and even buildings.
The benefits of good protocols are evident in healthy animals that maintain production and don’t require expensive veterinary treatments. This reduces costs – and contributes to judicious use of antimicrobials across the industry.
“The less disease you have, the less you need antibiotics,” Ramirez says. “It can even help with bacterial infections because, many times, viral infections can lead to secondary bacterial infections that cause more damage. We want pigs to be healthy, happy and minimize stressors. That can make welfare even greater.”
In addition to PEDV, porcine reproductive and respiratory syndrome (PRRS) is a persistent concern among pork producers, says Morgan Radford, senior manager, professional and technical services, at Virox Animal Health.
Production costs can be significant when producers face diseases like these, and others, she says.
“Only healthy animals can be harvested,” Radford notes. “If an animal is not marketed, a producer doesn’t get paid and any costs from raising the animal up until that point are lost. Even if the animal takes time to recover, it could require veterinary care and more feed and more days to market weight. In some cases, we might even have a whole herd culled. Not only do producers lose animals, but the barn loses productivity. In the cases of breeding stock, the time and investment in genetics is gone.”
The formula for disease is simple, Ramirez says. First, animals must be exposed to a live pathogen or virus. Second, that pathogen must be present in significant numbers.
“Pigs can fight off a low level of infection or attack,” he says. “As that exposure dose increases, it’s harder for the immune system to overcome it. Just having Salmonella present on the farm doesn’t mean sick animals unless we have Salmonella in high enough numbers.”
Cleanliness, disinfectants and biosecurity measures like restricting visitors help limit introduction of pathogens and can also decrease the potential pathogen load introduced on the premises.
Biosecurity protocols should be customized to each operation. Requiring clean clothes for everyone and disposable boots for visitors are typical requirements. If possible, showering before entering facilities helps reduce possible contamination.
“If you can’t shower, then washing hands when touching animals. Maybe I can put on disposable gloves – that’s another layer of extra safety. At the top of the process is decreasing contamination,” Ramirez says. “The challenge is really for the workers to have to do it every day. Sometimes we get into a routine, it gets hectic and we take short cuts. The days when everything breaks down, that creates risk.”
The only feedback to biosecurity occurs when a poor job is done, Radford says. When a disease is spreading rapidly, biosecurity often improves. However, people can become complacent.
“When people have been on high alert for a long time, fatigue can creep in and the perceived risk is lower,” Radford says. “We know when biosecurity isn’t working because there’s an outbreak.”
People can unknowingly track disease just from moving to different locations and not using dedicated boots at specific facilities, she says.
The first step in reducing the pathogen load is cleaning up. Yet, not everyone on the farm may have the same standard for “clean.” Training can help set a standard the whole team can work toward. Cleaning is also the step that takes the longest, which makes it a prime target for cutting corners to speed things up, Radford notes.
“It’s a time consuming and messy, dirty job that’s not overly pleasant,” she says. “Ideally, we would clean, then disinfect, any time animals are removed from a barn. The cleaning step is not overly complicated, but it’s critical to allowing the disinfectant chemistry to do its job.”
Typically, a detergent is needed to help break down organic matter on surfaces. Removing organic matter allows disinfectants to work. Many are inactivated by the presence of organic matter, which can be a waste of both time and product.
“If you have a pile of manure, and you add disinfectant, the organic matter isn’t going to allow it to work,” Ramirez says. “However, if you take an additional step and remove the large number of pathogens with a simple power washing, it will look clean and remove all the organic matter. Then we can start thinking about disinfecting.”
Detergents also help break down a biofilm, or a slimy buildup of bacteria on surfaces, he says. Different detergents can help break down proteins or fats more effectively. DSRs can help their customers choose a detergent for their cleaning needs.
Just like antibiotic choices, disinfectants are developed to target different pathogens. Radford advises producers choose a disinfectant with a wide spectrum of efficacy including virucidal, bactericidal and fungicidal activity.
“You want a product that will do everything, but we’ve got to set it up for success first with a good cleaning,” she says.
There is more to choosing the correct chemistry than just looking at efficacy. Consider:
- The safety profile of the disinfectant, since precautions needed to keep employees and animals safe will differ between chemistries.
- Environmental impact should also be assessed to ensure manure pits and lagoons are not negatively affected.
- Some disinfectants contain a surfactant package in their formulations, meaning they also have cleaning properties.
- Contact time – which is the amount of time a surface must remain wet in order to reach the pathogen kill-time – varies significantly between products.
Radford also advises producers to properly calibrate dilution equipment. This ensures enough product is used to disinfect the premises, but it isn’t wasted.
“Sometimes people think that a little more is good, so a lot must be better,” she says. “In the case where a dilution system is set up, if it’s not calibrated we don’t know what is being used. Team members must be properly trained on the equipment and products and comfortable with the chemistry. It can lead to not adding enough product to ensure disinfection.”
Some disinfectants can be corrosive to building materials. If so, a rinse may be required to ensure no irritants remain that could damage the infrastructure or animals’ skin. Some products have test strips available that can be used to verify that the correct concentration has been achieved, she notes.
Products must be applied according to label indications. Disinfection does not occur immediately: the proper contact time must be respected. If the product dries on the surface before the contact time has been reached, the disinfectant will need to be reapplied to ensure kill time has been met. Legacy chemistries will typically require between 10 to 30 minutes, Radford says. Newer technologies require only a five-minute contact time to help facilitate a quick turnaround.
“Ideally, we would then let the building completely dry,” Ramirez says. “All living cells require water or moisture. That is one more step in ensuring pathogens are removed and neutralized. Then, we can move the animals in.”
Ramirez notes that some operations may be more challenging to complete the full process. A farrowing house, for instance, often requires animals be moved in the same day, which doesn’t provide an opportunity for allowing the room to completely dry.
Protocols can be flexible depending on the animal, Ramirez notes. Baby animals are highly susceptible to disease. Thorough cleaning will pay dividends in improved viability. On the other hand, older animals have more robust immune systems.
“When we look at biosecurity in containing what we already have, the more we can decrease contamination, the less likely pathogens are to affect our pigs. Any time we can do cleaning and disinfecting, we should, but it’s a matter of balance.”
Top tips for cleaning and disinfecting:
- Train employees on the farm standard for cleanliness
- Use the correct detergent for the job
- Select the appropriate disinfectant for target pathogens
- Consider the safety profile, environmental impact, cleaning properties (if any) and contact time of the disinfectant
- Properly calibrate dilution equipment
- Always read and follow label indications of the disinfectant
- If possible, allow the clean surfaces to dry completely