Previous research has demonstrated that pigs can tolerate different water qualities and assessing water quality often takes a back seat. However recent research on water treatment has shown decreased sow mortality due to pelvic organ prolapse, indicating that there may be something going on with the water or the water distribution system. There has been anecdotal evidence of improvement in E.coli cases with water treatment as well.

“Ultimately we are a little bit more concerned as we're learning more about biofilms and we are administering medications into these water distribution systems and how could that ultimately impact antimicrobial resistance,” says Gabi Doughan, a post-doctoral research associate and clinical instructor in the Swine Medicine Education Center at Iowa State University College of Veterinary Medicine.

When looking  at water line biology as a biosecurity risk Doughan says producers and veterinarians need to start with the water source, whether that is surface, well or even municipal water. Groundwater used to be considered as a protected water source, however this may be more variable based on local geology and other risk factors. Contaminants can go through macropores in soil, move rapidly and reach deep wells. Some water conditions allow pathogens to maintain their infectivity and viability. For example, the Iowa Department of Natural Resources surveyed Iowa wells over a 15-year period and found roughly 40% contain fecal coliform bacteria.

“That doesn't necessarily mean that it's a problem or that there are pathogens directly in there but it indicates that fecal contamination could have occurred and the conditions are right that those pathogen coliforms are surviving there and therefore pathogens could also live in those conditions,” Doughan says. “Additionally, across the entire U.S. it's estimated about 30% of wells contain viruses. That was done from the human side with rotavirus and enteroviruses and I think it's important when we consider our livestock species that there's definitely a risk there.”

Inside the barn there's also some other dynamics  that can contribute to the degradation of water quality and the first is the water distribution system itself. Since water distribution system design is open and often “dead-end”, Doughan says they're not circulating and any debris or pathogen entering from the stock bucket or potentially the pigs themselves through the drinkers can contribute to biofilm development and potential debris that gets into the water lines. Biofilm development can also be fueled through the administration of vitamins, probiotics and potentially attenuated oral vaccines in water treatments.

Farms also tend to have hard water with high iron content and elevated pH. Minerals can adhere to the inside of the water lines creating a rough surface for any pathogen or organism, which can cause biofilm establishment in the system. Water line biofilms may also have an impact on treatments and cause problems with water restriction.

So how can biofilm development potentially reduce water line treatment efficacy? Doughan says water medicators have a dosing accuracy which can vary up to 30% and over time different types of medicator can wear, making dosing even more incorrect. This can also contribute to antimicrobial resistance.

Dirty stock buckets can be a pathogen source and can also inactivate other medication types. For example, running citric acid and then running a live oral vaccine in the same bucket may inactivate the vaccine. Improper stock solution formulations is also a common occurrence and low water pressure is conducive for biofilms to develop in stagnant water.

Decreased efficacy can also stem from water quality and water treatment mechanisms. “Maybe we're applying water treatment and also applying it at the same time as some of our preventative mechanisms (such as live attenuated oral vaccines) or treatments such as antimicrobials. However, the pH of water, the water hardness, and other trace minerals could potentially cause some interactions with some of these treatments,” Doughan says.

Biofilms can develop and harbor antimicrobial resistance genes, and drugs can accumulate in the extracellular polymetric substance. Antimicrobial resistance genes can be linked to drugs currently used and not used in swine production medicine.    

All of these factors can potentially have an impact on pig livability, Doughan says, and the reason she suggests pork production systems take the following actions on a regular basis.

Doughan says this research is rapidly evolving, and to stay tuned to future research and best practice guidelines for swine water distribution systems.